Building Octrees with Normal Vectors

This section provides a primer on how you can work with unlimited volumes of point clouds in NUBIGON by processing your point cloud files to octrees. 

Octrees can render unlimited volumes of point cloud data in real time. For the best performance, we recommend you to build an octree from your point clouds, especially if they are larger than 2-3 GB. NUBIGON can currently process LAS, XYZ, TXT, PTS, E57, and FARO SCENE project files (*.lsproj) to octrees. 

Building Octrees from LAS, XYZ, TXT, PTS, and E57

To start building an octree, select Tools > Big Data Processing > Octree from Files and choose point cloud files.

You can build an octree from multiple files in a single build operation.

Next, you will be prompted with the following Octree Options window:

Octree Name

Choose a unique name for the octree and avoid using non-English characters.

Offset

To enhance computational precision and avoid display artifacts, we recommend offsetting your data. Even still, NUBIGON preserves original coordinates for display and export. The dropdown menu Offset Type provides four options: Origin, User, Previous and None.

  1. If your data has coordinates with large values, offset to the Origin.
  2. If you are building octrees from multiple files that are spatially associated with each other in successive build operations, you should use the offset type Previous for the second file and onwards. This guarantees that the relative positions of the octrees are preserved.
  3. The offset vector can also be user determined by selecting the Offset Type User. If you would like to build an octree that is spatially referenced to an existing octree, then manually specify the offset vector displayed in the Object Inspector of the reference octree. 
  4. Not applying any Offset (Offset Type None) will process the data directly with the original coordinates. This may lead to the aforementioned issues. 

Advanced

Normal attribute: The default is checked so you can calculate the normals in a second step.

Enabling the option normal does not calculate the normals. This needs to be done in a separate step, see below.
If your free disk space is less than 3 times the size of the point cloud that you would like to build an octree from, consider unchecking this box to reduce the necessary free disk space. However, bear in mind, this will prevent you from calculating normals in a subsequent step.

Skip colorless scan positions: If your data has scan positions that do not contain RGB information, check this box to exclude those positions from the octree generation.

Force 8-bit colors: In certain cases, 3rd party software packages will export LAS files with 8-bit colors instead of 16-bit (as outlined in the LAS specs) resulting in colorless octrees. In these cases, re-generate the octree by enabling this option.  

Clicking OK will initiate the octree generation process, which may vary in time based on the size and characteristics of the original point cloud files. Once completed, the octree will appear in the models folder of the default project under the designated name. You can now import it to your scene and assign materials to it.

Place octrees from external resources into the models folder of the default project. Otherwise, you won’t be able to open them.
Do not alter the name of octree files and folders.

Building Octrees from FARO SCENE Project Files

For building octrees from LSPROJ files, select Tools > Big Data Processing > Octree from FARO SCENE Project and follow similar steps to those described above. 

The latest FARO SCENE Project file format is not supported yet.

Computing Normals

We recommend computing the normal vectors since a number of tools and features including lights and shadows as well as 3D drawing tools require normals to yield optimal results. After building an octree, import it to the scene and select it in the Object List. Then select Tools > Point Cloud > Normal Computation. This will prompt a window asking you to set the number of neighbors. The default is set to 12. Click OK to start the computation. Once completed, open the Object Inspector, assign a Splat Surface Rendering material to the octree, and check the box Has normals to activate normal vectors. 

For a video tutorial on how to build octrees, follow this link.

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