Point Clouds

A point cloud is a large set of points in a three-dimensional coordinate system. In most cases, a point cloud is the result of a 3D scanner proceeding. This device allows you to get an idea of the surface geometry of the scanned object.

Note

The Point object and the cloud point are different entities in the program.

In addition to coordinates, a point can contain additional information - metadata (attributes). Some metadata is the result of the scanning process (intensity, color, time, etc.), and some is added to the point when working with the cloud (class, normal, etc.).

Point cloud is a separate object, some of its properties can be viewed and edited in the Properties bar. In addition to specialized operations, standard editing commands are available for point clouds, such as move, rotate, scale, mirror, align.

Moving, rotating, scaling, flipping, aligning will be blocked if the Transformation status option is disabled.

You can also set the point cloud loading mode in the Properties bar.

For multi-user network access, it is possible to load a point cloud from an NPC file located on a network resource. When importing a network NPC file, the point cloud data are frozen and the absolute path to the NPC file is set. Any attempts to modify the data of the cloud itself (NPC file) become unavailable, and a link is established to the NPC file that was imported. Together, this allows multiple users to work on a single NPC file. At that, all commands to modify the cloud are fully applicable to such a cloud. A similar possibility to switch the cloud to this mode is provided by changing the Mode property of the Properties bar to the Frozen position. In this mode, the cloud (NPC file) is not re-saved!

Import of Point Clouds

Inserts point clouds to the current drawing from LAS, LAZ, BIN, PTX, PTS, PCD, TXT, XYZ, XYB, PLY, E57, RCS, RCP, NPC files. File formats are described in more detail in the Point Cloud Data Formats section.

Import from Text Formats

When importing point clouds from text files (TXT, XYZ, XYB), a separate import wizard dialog is displayed. It allows you to set the data interpretation rules for the imported file.

Options:

Special

Specifies the next line character, the line from which data starts and the characters that are interpreted as the start of a line with comments.

Separator

Specifies character that separates text file data. You can choose both predefined character (semicolon, tab character, comma, space), and set any other one.

Consider consequent separators one Specify a character used to separate whole and fractional parts of values

Data

Preview of text file data.

Result

Specify correspondence of text file columns to certain data types: point coordinates by X, by Y and by Z, intensity value, point color in RGB (red, green, blue).

The Data field displays 100 lines from the file, and the Result field displays 50.

Changing the Content Start Line value will display the next 50 lines.

The selection of columns is set according to the table filling. If the column is empty, then Off, if there is data, then On.

After Text Files Import Wizard is closed, the main point clouds Import dialog box opens.

Point Clouds Import Dialog Box

The Import dialog box allows you to specify what data to import and how. It gives visual representation of the file’s point cloud and get understanding of the data in the file.

The dialog that opens shows base parameters and visual representation of point clouds in imported file.

The import dialog allows you to:

• import several files at the same time;
• view detailed information about each file and its metadata values;
• set an individual point cloud transformation from each file using EPSG codes (if the point cloud has a coordinate system described by the EPSG code, or the user sets EPSG for it manually);
• organize a preview of a point cloud in 3D, as well as to select a spatial fragment in any perspective selected by the user;
• set units of measurement for source data, as well as manage drawing units and data conversion from source units to drawing units;
• specify the types of metadata to be imported from source data;
• specify the classes to be imported from the source data;
• set data thinning during import;
• set partition into clouds by classes, sources, echoes;
• split point clouds into blocks, both along the grid and along the flight line. In this case, the cloud is not loaded immediately into the drawing. A set of dwg files is created in the folder with the point cloud, each of which contains a block - a fragment of the cloud, obtained by splitting the source file in accordance with the specified parameters. The function is convenient to use to automate import, the resulting fragments can be loaded into the drawing separately, significantly reducing the amount of memory used;

• remove files from the downloaded list.

Options:

Selected file

Displays the path to imported file.

Preview

Preview displays all contents of the imported file. You can specify areas to import. By default, all points will be imported, However it is possible to specify one or more areas of diverse geometry instead of loading all file points. To select areas, you must activate the set of area selection tools:

Rectangle selection

Specifies a rectangular area whose points will be imported into the document. Several such areas may be defined.

Polygon selection

Specifies the polygon area whose points will be imported into the document. To stop specifying the area, right-click the mouse. Several such areas may be defined.

Invert selected

The tool allows you to invert the selected areas.

Select all

Select the entire contents of the file being imported.

Select by coordinates

Manually specifying the coordinates of the area whose points will be imported into the document. The button opens a dialog box, in the fields of which the coordinates of the full scan boundaries are indicated. To create an area in this case, the coordinates of the desired area are indicated in the fields.

Several such areas may be defined.

Allows you to completely remove all previously selected areas.

Reset selection

It is possible to undo and redo operations for creating selection areas.

UNDO, REDO selection

View locator, similar to that in the main window. Allows you to select standard views.

Enlarges, reduces, or displays the entire image in the preview window.

Show all files

Upon clamping, it turns on the mode of displaying the data of all files in the preview window. When unclamped, the mode of displaying only the data of the currently selected file works.

On/Off project mode

When unclamped, it activates the mode of importing into the current document. When clamped, it activates the project work mode. In this mode it is possible to split the resulting data set into blocks, create a project file, as well as a project mosaic drawing. In project mode, binding of classes to layers is blocked.

Edit project information Clicking this button opens the project description editing window. Only available in the project creation mode

Show axis

When clicked, activates the display of the project CS axes. Only available in the project creation mode

Rotate axis

Tool for setting a project coordinate system. Only available in the project creation mode

On/Off grid of blocks

Only available in the project creation mode

Specifies the size of blocks and their numbering mode (to automatically generate a number, you need to use round brackets in which to place the starting number. Only numbers are allowed inside curly brackets), number of blocks perpendicular to line and overlap width of blocks:

It is possible to measure distances in the preview window

The result of this mode is the creation of a split grid

On/Off blocks by flight line

Only available in the project creation mode

Specifies the size of blocks and their numbering mode (to automatically generate a number, you need to use round brackets in which to place the starting number), number of blocks perpendicular to line and overlap width of blocks:

is possible to measure distances in the preview window

Next comes the flight line selection

Only available in the project creation mode

Add block Works only in flightline splitting mode.

Allows you to create a new block where the user specifies.

Only available in the project creation mode

Remove block Works only in flightline splitting mode.

Allows you to delete an existing block.

Only available in the project creation mode

Edit block Works in both splitting modes (grid and flightline).

Allows you to change the block name manually.

On – Sjows all files.

Show all files Off – Shows only the last one

Enables vertical numbering; Enables horizontal numbering;

Enables start to end numbering;

Enables end to start numbering.

Switching block numbering

File Information

This section displays statistics on the points of the imported file. You can set the units of the cloud, its coordinate system, and adjust thinning.

It is possible to reduce the density of imported clouds, in case of its redundancy, by importing every second/third/tenth, etc. file points. To do this, check the Interval box and specify the sequence number of the imported point in the Import each <…> field.

Using the checkbox in the left corner of the panel, you can include this file in the import data set or exclude it. For text files, there is a format setting button in the upper right corner (a description of the text file import settings window can be found in the Text File Import Wizard).

Detailed file information

Further in the right corner there is a button for obtaining detailed information about a LAS or LAZ file, you can view the properties in a text dialog.

Convert to

Setting up coordinate systems works as follows. If the file does not have a georeference, then it can be selected manually.

Having selected the desired coordinate system, we proceed to specify the target coordinate system in the same way.

If the file has a georeference written to the file itself, then you do not need to select the source coordinate system, it will be automatically filled in when opening the file.

When importing multiple files, the target coordinate system cannot be set differently for different files. Changing the target coordinate system for at least one file will automatically change it for all.

Besides, if there are several source files and they have different source coordinate systems, when you click OK, a message appears asking for the same source coordinate systems or to set them to a target coordinate system.

Filter by metadata

This list contains all metadata (attributes) of points present in the file.

After import, the points will have only the attributes selected in this list. Unselected attributes will not be included in the document.

Filter by code

This list contains all the classes to which the points of the imported file have been distributed. If the cloud points had no classes, the list will be empty.

Only those points that belong to the classes selected in this list will be imported. Points of the classes that were not selected will not be included in the document.

Differentiation

By default, file points are imported into the document as a single cloud. However, it is possible to import points as multiple clouds. The division of points into clouds can be carried out according to various criteria.

Don’t separate Import one cloud regardless of the cloud number in imported file.

By codes Import points as separate clouds. Each cloud contains points with

its code and one cloud with unclassified points.

By reflections Each cloud contains points with its value reflection.

By clouds Divide points on the number of clouds in file.

By files In the By files separation mode, cloud objects (both entire clouds

and their parts located in external constraints) have the same

names as the files from which they were loaded.

In some cases, the splitting options may be blocked. If one file is loaded into the dialog, the splitting options By clouds and By files are blocked. Also, if there is no data in the cloud, the options By codes and By reflections may be blocked.

Note

Special option hides separate points to avoid nanoCAD braking. This option is enabled by default. Turn on Display all points in Point clouds – Settings menu to display all points of cloud. It is also not recommended to open files from the Desktop in Windows. Point clouds with more than 2.4 billion points are not supported. To be able to work with the data, you should split the point cloud into smaller parts using our import tools.

Export of Point Clouds

Command line: NPC_EXPORT

This command exports point cloud to different formats: LAS (1.2 and 1.4 versions), BIN, PTS, XYZ, PLY, E57, RCS. File formats are described in more detail in the Point Cloud Data Formats section.

1. The following dialog appears if point cloud has meta data. Select attributes to export in a file. If all checkboxes are turned off, then only point coordinates are exported without attributes.

2. Then specify file format, file name and path.

Extension of XYZ file depends on selected attributes: *.xyzciedlastrgb , - for all selected attributes, *.xyz. – without selected attributes.

If the cloud was clipped with one of clip or section commands, then only visible points are exported.

Note

Since a clip (or a section) creates for a certain view, then it is very important what model space view is current at the moment of the Export command launching.

If the point cloud has the Class attribute, then only points from visible, unfrozen, unblocked layers will be exported.

Command prompt:

Use all clouds in view? or [Yes/No]:

This prompt is displayed when there are more than one point cloud in the viewport.

Command options:

Yes Exports all visible points of all clouds from the viewport. All points, which are invisible in active viewport, because they are outside viewport margins, will be also exported. No Displays the following prompt: Select point clouds or [?]: Specify the cloud to be exported, or select ? option. ? Shows the following prompt in the command line:

Select an option or [Window/Last/Crossing/Box/ALl/Fence/WPolygon/CPolygon/Group/Add/R emove/Previous/AUto]:

Select the cloud with one of the options. (see Selection of Objects Using the Command Line section)

Point Cloud Project Manager

Point Cloud Project Manager allows you to manage the project created during the point cloud import process.

The dialog also has a context menu:

Open – Open the DWG block in a separate document.

Reload – Reload the cloud.

Unreference – Break the block’s connection with the current DWG.

Remove – Remove the block from the NPCP project completely and break all connections with it, this action is irreversible (a warning message appears).

Deselect – Remove the selection from the selected blocks.

Select all – Select all blocks in the project.

Double-clicking in the dialog box opens the Project information window, where you can add additional information about the project.

Note

In case of duplication of block names, a warning message is displayed.

Point Clouds Data Formats

Point clouds are datasets of vertex data in a three-dimensional coordinate system, usually defined by X, Y, and Z coordinates. The most common method for obtaining point cloud data is the use of 3D laser scanners or photogrammetric image processing techniques in software.

3D scanners use LiDAR technology, a remote sensing technology that uses laser pulses to collect data. The LiDAR system calculates how long it takes for the laser light wave to reach the target and return to the scanner using the speed of light, which is 299 792 458 m/s.

The measurement principles used in 3D scanners are pulsed and phase distance measurement methods, as well as a direct angular sweep method (triangulation method).

Laser 3D scanning technology is the most common method for obtaining point clouds.

There are several file formats for storing point cloud data, which, in addition to 3D coordinates, can carry additional information - metadata (attributes). Some metadata are the result of the scanner operation (scan color, intensity, echo number, scan angle, end-of-beam, edge of flightline, source ID, time), and some are added to 3D coordinates when working with the cloud (class, normal, deviations, geometry).

LAS

Initially, lidar data are received exclusively in ASCII format. With the accumulation of large amounts of lidar data, a binary format called LAS began to be used for work and became the standard format for organizing and distributing laser data. Lidar data in LAS format is quite common nowadays. LAS is the

most suitable format because files in this format contain more information and, being binary, they can be read more efficiently when imported.

LAS is an industry standard developed and used by the American Society for Photogrammetry and Remote Sensing (ASPRS). LAS is a standard file format for exchanging lidar data. It stores specific information related to lidar data. It is a way of exchanging data for suppliers and consumers, and storing all information specific to this data.

Each LAS file contains lidar metadata in a header block, followed by an individual entry for each laser pulse. The header portion of each LAS file contains attribute information about the lidar survey: data extents, date of flight, number of points recorded, number of echo points, any additional data, and applied scale factors. The following lidar point data attributes are stored in the LAS file for each laser pulse: X, Y, Z coordinates, GPS time, intensity, echo number, echo count, point classification values, scan angle, additional RGB values, scan direction, edge of flightline, user data, point source ID, wave information. The processed LAS file can include points classified as Ground, Low Vegetation, High Vegetation, Building, and so on.

Classification codes for LAS versions 1.1 – 1.4 assigned by ASPRS

LAZ

LAZ – LASzip- LAS format file compressed without data loss.

BIN (Terrasolid format)

Format of Terrasolid company.

The file structure looks as follows:

Point cloud attributes are stored in blocks: first a point coordinate block, then a time block, then an intensity block, etc.

The advantages of block storage:

• Possibility to read only the necessary attributes of points, this saves RAM and reduces the time for reading a file;
• You can save only the required attributes;
• Time stamps are now stored in GPS Standard Time format.

PTX (Leica Cyclone Format)

Format of Leica company, Cyclone program.

A simple text file for storing point cloud data. Consists of a series of header lines followed by lines consisting of vertices (X, Y, Z), scalar coordinates, and R, G, B color values, each ranging from 0 to 255 (sometimes floating).

The Leica header looks as follows.

number of columns
number of rows

st1 st2 st3 ; scanner registered position
sx1 sx2 sx3 ; scanner registered axis 'X' 
sy1 sy2 sy3 ; scanner registered axis 'Y' 
sz1 sz2 sz3 ; scanner registered axis 'Z' 
r11 r12 r13 0 ; transformation matrix 
r21 r22 r23 0 ; this is a simple rotation and translation 4x4 
matrix
r31 r32 r33 0 ; just apply to each point to get the transformed 
coordinate 
tr1 tr2 tr3 1 ; use double-precision variables

All point clouds in PTX format usually have brightness information, so every cloud will have this attribute. Color data is determined if there are seven elements on the dot line.

The coordinates of cloud points are calculated using the position recorded by the scanner, as well as the position of the scanner and the transformation matrix.

If the scanner position is specified in the user interface, the transformation matrix in the PTX header is still used to calculate the points coordinates.

E57

The most common file format for storing and exchanging 3D laser scanning data.

In general, an E57 file consists of a 48-byte header, a series of data blocks, and an XML section. The entire file, including the header, is divided into 1024-byte “pages”, 1020-byte data, and 4 bytes at the end as a checksum. This chunk nature even applies to the XML text / readable section after all chunks of data.

Example:

struct E57FileHeader {
 char fileSignature[8];
 uint32_t majorVersion;
 uint32_t minorVersion;
 uint64_t filePhysicalLength;
 uint64_t xmlPhysicalOffset;
 uint64_t xmlLogicalLength;
 uint64_t pageSize;
}

The E57 data format is supported by static and mobile 3D scanners, which are used to calculate point coordinates.

With mobile devices, point clouds and trajectory data are linked using time stamps. Therefore, at least one E57 scan should contain a field for timestamps. Trajectory information is required to import scan results from mobile devices. The trajectory file should contain a list of scanner positions associated with timestamps. The positions should be specified in the same coordinate system as the point cloud coordinates, and the trajectory timestamps should match the timestamps of the points.

Trajectory example:

Time;X;Y;Z
189321.10;15.96;-52.12;133.68
189321.20;15.21;-51.21;134.01
189321.30;14.75;-50.37;134.35
189321.40;14.10;-49.50;134.31

189321.10;13.78;-48.69;134.43
...

PTS

This is a simple text file obtained from LIDAR scanners. The first line contains the number of lines. Each subsequent line has 7 values, the first three are the coordinates (X, Y, Z) of the point, the fourth is the “intensity” value, and the last three are the color estimates (R, G, B). The R, G, B values range from 0 to 255 (one unsigned byte). The intensity value is an estimate of the fraction of incident radiation reflected by the surface at this point. The PTS format does not allow storing negative values of point intensity, therefore an additional option for selecting the original intensity format for subsequent recalculation into a standard one (0…65535) has been introduced in the import dialog. When importing into a document, the intensity range will always be 0…65535.

Example:

253730194 
-0.41025 -2.0806 8.00981 55 52 44 65
-0.63016 -1.84527 6.59447 228 228 230 225
-0.4766 -2.14446 7.91288 60 56 54 68
-0.52017 -1.51698 7.91458 60 58 50 71
-0.626 -2.46051 7.35187 152 140 160 161
-0.62371 -1.53502 7.46876 168 163 175 175
-0.62829 -2.27286 6.34905 208 204 213 212
-0.62614 -2.48739 7.36484 151 144 155 159
 : : :
 : : :
 : : :

PCD

The format is created to optimize point cloud data, currently the latest version is 0.7 (PCD_V7).

Each PCD file contains a header that identifies and declares specific properties of the point cloud data stored in the file. The PCD header must be ASCII encoded. Header entries must be listed in the exact order shown below:

VERSION
FIELDS
SIZE
TYPE
COUNT
WIDTH
HEIGHT
VIEWPOINT
POINTS
DATA

TXT

Simple text format of 3-dimensional coordinates, separated by spaces, contains at least 3 columns of data (X, Y, Z).

XYZ

This is a simple text format for the coordinates of 3-dimensional points, separated by spaces, containing 7 fields per point. The problem is that due to the lack of specifications for the content of the point cloud file, the content of the fields can vary depending on where and by whom it was created. The main thing is that the first 3 columns always represent the X, Y, Z coordinates, and the rest of the columns represent some scalar field associated with this point (R, G, B or Nx, Ny, Nz, etc.).

XYZ format can be presented in both text and binary types.

XYB (Faro)

The binary format of the XYZ file. It can also contain attribute data in addition to the coordinates of points.

PLY

A polygonal storage format for graphic objects that are described as a set of polygons. The file format has two representations - text and binary. The PLY format contains the description of vertices, faces and other elements, their properties such as color, surface normal, textures, transparency, and various properties for the top and bottom surfaces of polygons. Typical information contains only two elements: the coordinates (X, Y, Z) for the points vertices and the vertex indices for each face.

The PLY format supports the creation of new properties for objects, but if new properties are not understood or defined in third-party software, they can be ignored.

The structure of a typical PLY file:

Header
 Vertex List
 Face List
 (lists of other elements)

NPC (nanoCAD Point Cloud Storage Format)

It is the main format for storing and exchanging point cloud data in the nanoCAD environment.

The NPC format is a spatially indexed optimized container for a single point cloud with support for levels of detail. The format is capable of storing not only the cloud geometry, but also meta-information: the echo intensity, the number of echoes, signs of the scanning system position for the data obtained during laser scanning, the point color, the point class, its belonging to geometric shapes, the data source ID and the time of its registration, as well as calculated information: normal and curvature at a point. The structure of the container allows you to work with it by partially projecting data into memory.

RCS (ReCap Format)

Point cloud storage format of the Autodesk ReCap software after importing scanned point cloud files into it (formats that are indexed in ReCap: ASC, CL3, CLR, E57, FLS, FWS, ISPROJ, LAS, PCG, PTG, PTS, PTX, RDS (3D only), TXT, XYB, XYZ, ZFS, ZFPRJ). Point cloud data saved in RCS format are in meters.

RCP (Autodesk Native Format)

The file format is a project file that groups multiple scan files at the same time. RCS, which actually contains links to individual RCS files and contains information about them and preview files. The result

of indexing a source format file is a .RCP file and one or more .RCS files. The internal structure of the file is xml

Extract from View

This command extracts points from viewport to a new point cloud. If source point cloud was clipped with one of clip or section commands, then only visible points includes in a new cloud.

Command Prompt:

Use all clouds in view? or [Yes/No]: This prompt is displayed when there are more than one point cloud in the viewport.

Command options:

that allows you to select a cloud using various options (see Selection of objects using the command line options section)

Create a New Cloud Based on Clipping

Command line: NPC_CROP_FROM_VIEW

The command creates a new point cloud from the crop of the existing cloud. In this case the source point cloud is deleted.

To create a new cloud from crop:

• 1. Go to the model space viewport containing the clipped cloud and run the command.
• 2. If there are several clouds the command line will show a prompt to specify the necessary:

Use all clouds in VScreen? <No> or [Yes/No]:

3. After specifying, the selected clouds will be deleted, and new ones will be created in their place from their clippings.

Note

When this command is undone, clipping on the source clouds is not restored.

Point Clouds Coordinates Transformation

Transformation to Defualt Coordinates

Ribbon: Point Clouds – Point Cloud > Transform to Default Coordinates

Menu: Point Clouds > Transform to Default Coordinates

Toolbar: Point clouds > Transform to Default Coordinates

Command line: NPC_TRANSFORM_TO_DEFAULT_COORDINATES

The command allows you to convert point cloud coordinates from the Own or User coordinate system to the World coordinate system.

It is usually used to transform the coordinates of those clouds that were taken in the own coordinate system.

Command prompts:

Do you want to transform object coordinates from UCS to WCS or from OCS to WCS or [UCS/OCS]:

Specify from which system the cloud coordinates should be converted to the World coordinate system: from UCS or OCS.

Recalculation of Point Cloud Coordinates by EPSG

Ribbon: Point Clouds – Point Cloud > Recalculation of Point Cloud Coordinates by EPSG

Menu: Point Clouds > Recalculation of point cloud coordinates by EPSG

Toolbar: Point cloud > Recalculation of Point Cloud Coordinates by EPSG

Command line: NPC_EPSG_REPROJECTION

If the loaded point cloud has geocoordinates, the command allows you to recalculate them to another system using EPGS codes. This creates a new cloud for the target coordinate system.

The Recalculation of point cloud coordinates and Recalculation of point cloud coordinates by EPSG commands are mutually exclusive. Use one of them to convert geocoordinates of a cloud.

To recalculate coordinates:

• 1. Run the command.
• 2. In the right text field of the dialog that appears, enter the number of the target coordinate system according to the EPGS classification, based on the information in the left part of the window. Click Apply.

3. Information on the selected target geocoordinate system will appear in the right part of the dialog box. Click OK to confirm the conversion.

Information about the current geocoordinate system of the cloud can be viewed by clicking the button from the Properties bar (Geoinfo bar) or from the Coordinate system information dialog.

Point Clouds Display Settings

Display Settings

Display boundary

Enable/disable boundary box of each point cloud in the drawing. By default, this mode is turned off, as a result of which bounding contours are not displayed.

Display All Points

Ribbon: Point Clouds – Settings > Switch point cloud display tree

Menu: Point Clouds – Settings > Display all points

Toolbar: Settings and Information > Switch point cloud display tree

Command line: SWITCHPCDISPLAYTREE

Turns on / off the display of all points in the cloud. Disabled by default, so the number of points displayed on the screen depends on the performance of the PC’s graphics system.

Enabling this mode only affects the speed of displaying clouds and navigation in the workspace. This mode does not affect the speed of clouds processing by commands of stitching (registration), classification, etc. To speed up cloud processing operations, make it sparse with the Thinning the Point Cloud command, which reduces not the displayed, but the actual number of points in cloud. It is also possible to reduce the number of cloud points that get into the document during the import operation by checking the Spacing box and specifying the sequence number of imported points.

Zoom Extents after Import

Ribbon: Point Clouds – Settings > Switch point cloud import zoom extents

Menu: Point Clouds – Settings > Zoom extents after import

Toolbar: Settings and Information > Switch point cloud import zoom extents

Command line: SWITCHPCIMPORTZOOMEXTENTS

Auto zoom extents mode to the point cloud after import.

In the majority of cases after importing it is required to zoom to the point cloud. This mode does this automatically. The mode is enabled by default.

Snap Point Cloud

Ribbon: Point Clouds – Settings > Snap Point Cloud

Menu: Point Cloud – Settings > Snap Point Cloud

Toolbar: Settings and Information > Snap Point Cloud

Command line: SWITCHPCSNAPON

Snap to separate points in Node object snap mode. The mode is enabled by default.

Snap to Geometry

Ribbon: Point Clouds – Settings > Snap to Features

Menu: Point cloud – Settings > Snap to Features

Toolbar: Settings and Information > Snap to Features

Command line: SWITCHPCSNAPFEATURES

Allows you to snap to fit points of geometry, recognized in the cloud by features recognition commands. By default, the mode is on.

To be able to snap to shapes, the Object 3D Snap mode should be enabled and the required snapping types should be turned on in the Drafting Settings dialog box called from the context menu of button.

Point Cloud Display Style

The command opens View Mode that allows you to stylize a point cloud in accordance with the values of these or those attributes of this cloud. In fact, the command paints each cloud point in accordance with the attribute value in this point. The user selects the attribute by stylize by. In case the necessary attributes are present in the cloud, stylization is possible by:

• color;
• intensity;
• class;
• echo number;

• source ID.

Also, you can color point cloud by selected color or cloud elevation (along the Z axis).

Options:

When enabled, the selected cloud is not highlighted.

The buttons toggle the display of the recoloring result after the Apply button is pressed.

The size of points in cloud in pixels. The size of deviation and normal vectors also depends on this parameter.

Coloring type: The list of available attribute values.

A drop-down list of cloud attributes available for stylization. The number of attributes in the list depends on which of them were imported together with the cloud from the scan file.

The number of ranges of the same color into which the entire cloud will be divided when coloring. This field is available when coloring by elevation, intensity, or deviation value.

It is possible to turn off multiple forms by first selecting them using SHIFT.

Scan Color

Color the cloud according to points color in the source file.

Elevation

Coloring depends on the Z-coordinate value in each point of cloud.

Intensity

Coloring based on the intensity of the reflected pulse(Intencity attribute).

Code

Color the cloud according to point classes. Points can be classified into a number of categories including bare earth or ground, top of canopy, and water. This coloring type may color the cloud with the Standard LAS Classification.

Echo number

Coloring a cloud according to the sequential number of the laser beam reflection at a certain point, obtained during scanning.

Color

Coloring all points of the cloud with any selected color.

Source ID

Coloring point cloud according to a unique source scan ID. One cloud can be formed as a result of several scans of one and the same object from different points. This type allows you to color the cloud points depending on the identifier of the scan source.

Program selects color for every source automatically.

Normal

Renders the direction of cloud point normals (Normal attribute), if present in the cloud. It is possible both to color the points depending on the normal direction, and to directly display the normal vectors. Cloud points are colored according to the direction of their normals.

Normals are created by cloud triangulation commands, features recognition commands, and fitting commands. Normals may not always be calculated correctly. In this case, it is recommended to recalculate the normals.

When the Half-space normals box is checked, all collinear normal vectors begin to be displayed in the same color. So coloring does not distinguish between normals pointed in exactly opposite directions. This assigns them color equal to the interpolation of the colors of the axes of the current UCS. Points with normals collinear to a particular coordinate axis will have the color of that axis.

You can check the Normals as vectors box to display the normal vectors, and not just color the points of the cloud according to the directions of the normals. The size of the vectors on the screen depends on the size of the cloud point (Point size field). Normal vectors are only displayed when using DirectX as a hardware graphics accelerator.

Feature and Feature type

The Feature type and Feature coloring become available for point clouds in which features have been recognized by geometry search commands (pipelines, pipeline elements, planes, plane and pipe elements). These coloring types are designed to visualize such features in the cloud.

Clips

At the bottom of the toolbar, there is the Clips section, which is responsible for clips (in this case, breakdown by some geometric features), which can be:

• named views
• division by codes
• by features
• by feature types
• by echo number

If the cloud has the necessary attributes, the corresponding clip type will be displayed in the window at the bottom of the toolbar. A cloud can have several clips.

Hiding the Point Cloud

The command allows you to hide visibility of a selected point cloud or all point clouds in a drawing. If there are no selected point clouds, then the command disables all of them. If there is a selected item(s), they will be hidden.

Displaying a Point Cloud

Toolbars: Point Clouds > Displaying a Point Cloud

Command line: NPC_SHOW

The command restores visibility of all hidden point clouds.

Clip Point Clouds

Clip tools allow you to crop a specified area from a cloud or several clouds.

Clip area from point cloud in any view. Specify needed viewport to show clipped point cloud.

The work of clip commands changes only the cloud display in the target viewport. No changes occur to the object cloud itself. Other viewports display original cloud.

Clip boundary set in the plane of view in the eye direction. It’s possible to clip the cloud in one viewport and display clipped cloud in another one. When the clip result is displayed in the target viewport, the same view will be set that was in the original viewport during clipping operation.

You may clip the cloud repeatedly. Clip undo realized by special commands: NPC_CLIP_UNDO to undo the last clip and NPC_CLIP_RESET to undo all clips. Commands are not related with standard UNDO command.

Clip Point Clouds by 2 Points of Rectangle

Create clip boundary by two opposite points of rectangle. Boundary is perpendicular to the view plane. Its sides are orthogonal to sides of the viewport. The cloud is clipped perpendicular to the plane of the viewport in the view direction.

A cloud can be clipped in one viewport (source), with the result displayed in another viewport (target), specified by the user. When the clip result is displayed in the target viewport, the same view will be set that was in the original viewport during clipping operation.

Command options:

As a result of the Clip by 2 Points (inside) command, the cloud area inside the rectangle frame will be clipped.

As a result of the Clip by 2 Points (outside) command, the cloud area outside the rectangle frame will be clipped.

Command clip only mapping of point cloud in the target view, the object cloud itself remains unchanged. The cloud remains unchanged in the rest of viewports.

Clip Point Clouds by 3 Points of Rectangle

Command line: NPC_CLIP_RECT_ROTATED, NPC_CLIP_RECT_ROTATED_INV

Create rectangle clip boundary by angle and two sides. Boundary is perpendicular to the view plane. The cloud is clipped perpendicular to the plane of the viewport in the view direction.

A cloud can be clipped in one viewport (source), with the result displayed in another viewport (target), specified by the user. When the clip result is displayed in the target viewport, the same view will be set that was in the original viewport during clipping operation.

Command options:

As a result of the Clip by 3 Points (inside) command, the cloud area inside the rectangle frame will be clipped.

As a result of the Clip by 3 Points (outside) command, the cloud area outside the rectangle frame will be clipped.

Command clip only mapping of point cloud in the target view. The cloud remains unchanged in the rest of viewports.

Clip Point Clouds by Fence

Clip the cloud by polygonal boundary. Boundary is perpendicular to the view plane. The cloud is clipped perpendicular to the plane of the viewport in the view direction.

A cloud can be clipped in one viewport (source), with the result displayed in another viewport (target), specified by the user. When the clip result is displayed in the target viewport, the same view will be set that was in the original viewport during clipping operation.

Command prompts:

As a result of the Clip by Fence (inside) command, the cloud area inside the frame will be clipped.

As a result of the Clip by Fence (outside) command, the cloud area outside the frame will be clipped. Command clip only mapping of point cloud in the target view. The cloud remains unchanged in the rest of viewports.

Clipping Clouds by Sphere

Toolbar: Clip and Sections > Clip by Sphere (inside)

Toolbar: Clip and Sections > Clip by Sphere (outside)

Command line: NPC_CLIP_SPHERE, NPC_CLIP_SPHERE_INV

The command clips a cloud by sphere set by central point and radius.

A cloud can be clipped in one viewport (source) with display of the result in the other viewport (target) specified by the user. When displaying the clip result in the target viewport, the same view will be set that was in the source viewport when performing the clip operation.

Command prompts:

Enter central point: Specify the clip sphere center. Enter radius or [Invert]: Specify the clip sphere radius. To invert the clip area, select the Invert option. In this case, the area outside the sphere will be clipped. Select view: Specify the target viewport, in which to display the clip. This prompt is displayed in case there are several viewports in the model space.

As a result of the Clip by Sphere (inside) command, the cloud area inside the sphere will be clipped.

As a result of the Clip by Sphere (outside) command, the cloud area outside the sphere will be clipped.

Only display of the cloud in the target viewport is changed as a result of the command work, the cloud object itself is not changed. Display of the cloud in other viewports remains the same.

Clipping Clouds by Cylinder

Ribbon: Point Clouds – Clip and Section – Clip > Clip by Cylinder (inside)

Ribbon: Point Clouds – Clip and Section – Clip > Clip by Cylinder (outside)

Menu: Point clouds – Clip > By Cylinder (inside)

Menu: Point clouds – Clip > By Cylinder (outside)

Toolbar: Clip and Sections > Clip by Cylinder (inside)

Toolbar: Clip and Sections > Clip by Cylinder (outside)

Command line: NPC_CLIP_CYLINDER, NPC_CLIP_CYLINDER_INV

The command clips a cloud by cylinder area set by central point and radius. The cylinder bases are collinear to the plane of the viewport. A cloud is clipped perpendicular to the viewport plane in the direction of view.

A cloud can be clipped in one viewport (source) with display of the result in the other viewport (target) specified by the user. When displaying the clip result in the target viewport, the same view will be set that was in the source viewport when performing the clip operation

Command prompts:

As a result of the Clip by Cylinder (inside) command, the cloud area inside the cylinder will be clipped.

As a result of the Clip by Cylinder (outside) command, the cloud area outside the cylinder will be clipped.

Only display of the cloud in the target viewport is changed as a result of the command work, the cloud object itself is not changed. Display of the cloud in other viewports remains the same.

Clip Undo

You may clip the cloud repeatedly. Clip Undo cancels the last clip of the point cloud.

This command cancels the last clip in the specified viewport and returns the cloud display to the same view it was on the target screen when the last clip was set.

Reset All Clips

It is possible to perform several successive cloud clips, including in combination with cloud sections.

This command undoes the entire sequence of cloud clips in the current viewport and displays the clouds in their original form. The display of clouds in other viewports remains the same.

Point Clouds Section

Point clouds section is used to display needed part of the cloud. To create section, first determine the plane. UCS moves to this plane after section. Section changes only cloud mapping in specified view. Cloud section made only in one of the orthogonal views depending on the type of section.

Just as with clipping operations, as a result of the section commands, the cloud visibility changes only in the target viewport; no changes occur to the object itself. The display of cloud in other viewports remains the same.

Unlike cloud clipping operations, when creating a section, the position of the user coordinate system in the target viewport changes, which greatly simplifies the subsequent “rendering” of the resulting part of the section by constructing vector objects in the UCS plane.

Point Clouds Unrestricted Section

Menu: Point Clouds – Section > Unrestricted

Toolbar: Point Clouds > Unrestricted Section

Command line: NPC_SECT_UNRESTRICTED

Unrestricted section is performed by 3 points perpendicular to view plane. If there are several viewports in the model space, then it is necessary to specify in which viewport the section result will be displayed.

First and second points determine the vertical plane of section. Third point determines the depth of section.

Create unrestricted section:

• 1. Run the command.
• 2. Specify the first point of section. This point will be located to the left of observer.
• 3. Specify the second point of vertical section. This point will be located to the right of observer.
• 4. Specify the depth of section.
• 5. Select needed view to display the section.

Point Cloud Horizontal Section

Ribbon: Point Clouds – Clip and Section – Section > Horizontal Section

Menu: Point Clouds – Section > Horizontal

Toolbar: Point Clouds > Horizontal section

Command line: NPC_SECT_HORIZ

Horizontal section is performed in Right, Left, Front and Back views and in the result view of vertical section.

Horizontal section performed by 2 points. First point determines vertical plane of section (middle elevation point). Second point determines the section.

Create horizontal section:

• 1. Set Right, Left, Front or Back view or the result view of vertical section.
• 2. Run Horizontal section.
• 3. Specify the middle elevation point of section.
• 4. Specify the depth of section.
• 5. Select needed view to display the section.

Point Cloud Vertical Section

Ribbon: Point Clouds – Clip and Section – Section > Vertical Section

Menu: Point Clouds – Section > Cut

Toolbar: Point Clouds > Vertical Section

Command line: NPC_SECT_CUT

Vertical section is similar to vertical section in Right, Left, Front, Back view or the result view of vertical section. Section plane is perpendicular to the current view plane.

Vertical section performed by 2 points. First point determines vertical plane for section. Second point determines the section depth.

Create cut section:

• 1. Set Right, Left, Front, Back view or the result view of vertical section. Section plane is perpendicular to the current view plane.
• 2. Run the Vertical Section command.
• 3. Specify cut position in section view.
• 4. Specify section depth. This point determines the observer position in result view.
• 5. Select required view to display the section.

Clip Invert

Ribbon: Point Clouds – Clip and Section > Clip Invert

Menu: Point Clouds – Clip > Invert

Toolbar: Clip and Sections> Clip Invert

Command line: NPC_CLIP_INVERT

The command hides all visible cloud points and displays all points hidden as a result of clipping or sectioning. Applies to the active viewport.

Copying a Clip to the Selected View

Ribbon: Point Clouds – Clip and Section > Copying a Clip to the Selected View

Toolbar: Clip and Sections > Copying a Clip to the Selected View

The command clips the point cloud of the current model space viewport, similar to clipping a cloud in the specified viewport.

To copy a cloud clipping from another viewport:

• 1. Go to the model space viewport in which the cloud is to be clipped.
• 2. Run the command. The prompt will appear in the command line:

Select view to clone:

• 3. Click the model space viewport containing the clipping you want to copy.
• 4. The cloud in the original viewport is clipped identically to the cloud in the selected one.

Isolate Features

The commands for managing features apply to point clouds in which geometric features have been previously found: pipelines, pipeline elements, planes, and plane elements.

The commands are used to create a temporary view when it is necessary to hide the selected features, or to isolate - to leave only the selected features visible, while hiding all others.

You can identify the presence of features in a cloud in the View mode window – for clouds with recognized features, the Feature and Feature type coloring types will be available.

The feature isolation commands work with any type of cloud coloring, but coloring by features makes the work with commands the most visible.

• Hide Feature hides the display of the specified features.
• Hide All Features hides the display of all features, leaving unrecognized parts of the cloud visible.
• Isolate Feature keeps the feature selected for isolation visible, hiding the rest of the cloud.
• Isolate All Features leaves all features displayed, hiding unrecognized parts of the cloud. If any cloud features have been hidden, their display is restored.
• Show All Features if at least one cloud feature was hidden, the command restores the display of all features without changing the display status of the unrecognized part of the cloud. If all cloud features were displayed, the command hides the unrecognized part of the cloud.
• Feature Isolation Reset resets features isolation, showing all parts of the cloud.

Note

Isolation of features, in contrast to the isolation of objects, is carried out within the framework of the general mechanism of cancellation-return of actions (UNDO/REDO).

Hiding a Feature

Ribbon: Point Clouds – Managing Features > Hide Feature

Menu: Point clouds – Managing Features > Hide Feature

Toolbar: Point clouds > Hide Feature

Command line: NPC_HIDE_FEATURE

The command allows you to hide the display of specified features.

Hiding All Features

Menu: Point clouds – Managing Features > Hide All Features

Toolbar: Point clouds > Hide All Features

Command line: NPC_HIDE_ALL_FEATURES

The command hides the display of all features, leaving unrecognized parts of the cloud visible.

Isolating a Feature

The command leaves the feature selected for isolation visible, hiding the rest of the cloud. There can be several clouds, the command allows you to select features in different clouds.

Command prompts:

Select Features to isolate [Isolate features]:

Selection of features to isolate.

Isolation is applied by selecting the “Isolate” keyword.

Isolating All Features

Ribbon: Point Clouds – Managing Features > Isolate All Features

Menu: Point clouds – Managing Features > Isolate All Features

Toolbar: Point clouds > Isolate All Features

Command line: NPC_ISOLATE_ALL_FEATURES

The command displays all features, hiding unrecognized parts of the cloud. If any cloud features have been hidden, their display is restored.

Showing All Features

Ribbon: Point Clouds – Managing Features > Show All Features

Menu: Point clouds – Managing Features > Show All Features

Toolbar: Point clouds > Show All Features

Command line: NPC_SHOW_ALL_FEATURES

If at least one cloud feature was hidden, the command restores the display of all features without changing the display status of the unrecognized part of the cloud.

If all cloud features were displayed, the command hides the unrecognized part of the cloud.

Feature Isolation Reset

Menu: Point clouds – Managing Features > Feature Isolation Reset

Toolbar: Point clouds > Feature Isolation Reset Feature Isolation Reset

Command line: NPC_UNISOLATE_ALL_FEATURES

The command resets the features isolation, showing all parts of the cloud.

Information

Get info about selected point cloud or specific point. Properties toolbar shows some info.

Point Cloud Comparison Widget

Enabling the Point Cloud Comparison Widget

Enables a widget that displays the results of commands in the form of a deviation distribution chart in the right side of the viewport.

Ribbon: Point Clouds – Information > Enabling the Point Cloud Comparison Widget

Menu: Point Clouds – Information > Enabling the Point Cloud Comparison Widget

Toolbar: Settings and Information > Enabling the Point Cloud Comparison Widget

Command line: NPC_COMPARE_LEGEND_ON

A similar diagram of the distribution of deviations can be viewed in the View Mode dialog for the Deviation value coloring type.

Disabling the Point Cloud Comparison Widget

The widget can be disabled by the NPC_COMPARE_LEGEND_OFF command

Ribbon: Point Clouds – Information > Disabling the Point Cloud Comparison Widget

Menu: Point Clouds – Information > Disabling the Point Cloud Comparison Widget

Toolbar: Settings and Information > Disabling the Point Cloud Comparison Widget

Command line: NPC_COMPARE_LEGEND_OFF

Point Cloud Info

Ribbon: Point Clouds – Calculations and Info > Point Cloud Info

Menu: Point Clouds – Calculations and Info > About Cloud

Toolbar: Point Clouds > Point Cloud Info

Properties toolbar – Misc – Point cloud info > button

Command line: NPC_INFO

Displays statistic information about point cloud and excludes/includes certain point cloud attributes.

Statistics

Statistics displays the number of cloud points, nodes and levels in the point cloud structure tree, their maximum and designation.

The button next to the Nodes count option opens a diagram of the distribution of points by nodes of the cloud tree.

A diagram of the distribution of nodes (vertical diagram) by levels of the structured cloud tree (horizontal diagram) can be viewed by clicking the button next to the Levels count option. By moving the right or left borders on the distribution diagram, you can cut off the display of cloud points belonging to certain levels of the hierarchical structure. On the drawing, such points will disappear.

The Points in current viewport parameter shows how many cloud points are actually displayed in the current view, including all clippings and sections. The history of clippings and sections of the point cloud can be viewed by clicking the Clipping history button.

Cloud Attributes

The Storage structure section displays information on the presence or absence of certain attributes of points of the could imported into a document.

The list contains a list of existing cloud point attributes. The window on the right displays a description of the selected attribute.

The button unloads (deletes) the selected attribute from the cloud. This removes all information on this attribute from the point cloud in the document. After unloading, the possibility to carry out operations using the unloaded attributes, including coloring the point cloud by this attribute, is lost.

Note

Attributes unloaded only from the current document. External file with point cloud is unchanged.

It is possible to add missing attributes with the button and then select them from the list in the Add metadata types dialog.

However, it should be understood that newly created attributes do not carry any values.

So, unloading such an attribute as Intensity from the cloud will lead to a complete loss of intensity values for the points of this cloud in the document.

If this attribute is later added with the button, the intensity values will not be restored.

If originally the cloud did not have Class attribute, enabling the create layer box will automatically create a new layer with the name Created, never classified (code 0) and assign class 0.to all cloud points

The button next to some attributes allows you to view the diagram of the distribution of the values of this attribute. This is possible for such attributes as Intensity, Class and Echo number. If there are no attribute values, the chart is not displayed.

Geoinformation

Point clouds imported from some types of formats (LAS, LAZ) can be geo-referenced. In the Georeference section, by clicking the Georeference information button, you can view detailed information about the coordinate system and georeference of the cloud.

The same information for the cloud selected in the workspace can be viewed in the Properties bar in the Geoinfo section.

Point Info

Point info displays information about point in the Properites bar. When running the command, the cursor changes to a cross and the Node snap symbol appears.

If there are recognized geometric features in the cloud, it is possible to view the geometric parameters of these features, as well as manage their visibility – isolate or disable their display.

To isolate or hide a feature, click the Feature option in the Properties bar. Two buttons will appear.

Allows you to hide the feature whose point was selected in the Point Information command. The result is similar to that of the Hide Feature command.

Allows you to hide the feature whose point was selected in the Point Information command. The result is similar to that of the Isolate Feature command.

Determining the Radius

The command for determining the radius allows you to get data on the radius of pipes and cylinders recognized in the point cloud in a form that allows you to transfer this information to other commands in the nanoCAD environment. The command is “transparent” and can be launched over an already running command. For example, the task is to draw a circle centered on the axis of a recognized pipe and with the radius of this pipe. To solve this problem, you can set up a 3D snap on the axis of the recognized geometry. Run the command to draw a circle by center and radius. Select the center point of the circle, the circle drawing command will ask for the radius. After that, without exiting the circle drawing command, run the radius determination command. Select the point of the pipe on the axis of which we have chosen the center of the circle. The command for determining the radius is completed and fills in the command line request to set the radius with the value of the pipe recognized in the cloud. The second scenario for using the command for determining the radius involves its isolated call. By calling the radius determination command, we can fill the clipboard with the radius of the pipe or

cylinder we are interested in. This feature will allow you to interact with commands whose parameters are set through modal dialogs. Having remembered the radius value in the clipboard, when calling such a command, we can fill in the required field in the dialog with the radius value.

Determining the Diameter

Menu: Point clouds – Information > Determining the Diameter

Toolbar: Point clouds > Determining the Diameter

Command line: _NPC_DIAMETER

The command for detecting the diameter allows you to obtain data on the diameter of pipes and cylinders recognized in the point cloud in a form that allows you to transfer this information to other commands in the nanoCAD environment. The command is “transparent” and can be launched over an already running command. For example, the task is to draw a circle centered on the axis of a recognized pipe and with the diameter of this pipe. To solve this problem, you can set up a 3D snap on the axis of the recognized geometry. Run the command to draw a circle by center and diameter. Select the center point of the circle, the circle drawing command will ask for the diameter. After that, without exiting the circle drawing command, run the diameter determination command. Select the point of the pipe, on the axis of which we have selected the circle center. The command for determining the diameter is completed and fills in the command line request to specify the diameter with the value of the pipe recognized in the cloud. The second scenario for using the command to determine the diameter involves its isolated call. By calling the command to determine the diameter, we can fill in the clipboard with the diameter of the pipe or cylinder we are interested in. This feature will allow you to interact with commands whose parameters are set through modal dialogs. Having remembered the diameter value in the clipboard, when calling such a command, we can fill in the required field in the dialog with the diameter value.