TLS/GBL Sensor Compute Points Visibility

[raazui]

Hi,

I am fairly new to CC, and having difficulty using the Edit>Sensor>TLS/GLS> compute points visibility (with depth buffer) feature to determine sensor shadowing caused by a mesh object (.STL file generated from SolidWorks) onto an point cloud (.las from survey LIDAR). What I am trying to achieve is to have the compute points visibility feature classify the points of the lidar point cloud which are shadowed/occluded by the mesh object (.STL solidworks CAD model) in relation to the TLS/GLS sensor object I have created. The compute points visibility does not seem to be working with mesh objects at all as it does not appear in the Depth Buffer (see below),

Depth Buffer.PNG (1.03 MiB) Viewed 1418 times

or Sensor Visibility scalar field (see below).

Sensor Visibility.PNG (250.06 KiB) Viewed 1418 times

I have also tried tried subsampling the mesh into a point cloud and then merging it with the LIDAR scan to see if the compute points visibility function only works with point clouds. Unfortunately the the hydraulic machine arms barely show in the depth buffer (see below)

Depth Buffer with Subsampled Mesh.PNG (1.15 MiB) Viewed 1418 times

and do not cause any points behind them to be classified as not visible when the compute points visibility function is run.

Sensor Visibility with Subsampled Mesh.PNG (74.92 KiB) Viewed 1418 times

for reference I took a LIDAR scan of same machine within another environment and the shadowing very evident (see below).

Sensor Visibility with LIDAR mounted.PNG (663.67 KiB) Viewed 1418 times

Please advise what is the proper procedure for using the compute points visibility feature, I have tried looking at the documentation but cannot find what I am doing wrong, as the picture in documentation seems to be a very similar situation but classifies the points correctly.
https://www.cloudcompare.org/doc/wiki/i ... pth_Buffer

Additionally is there any way to set the angular FOV spans for the sensor configuration, I am only able to enter in the Yaw and Pitch steps not the range which seems to be determined automatically from the software.

Cheers,

Raazi

[daniel]

Indeed, meshes are not supported. You could use the vertices instead of the mesh, but I'm not sure what the end result will look like. The other option is to convert the CAD mesh to a dense point cloud (with Edit > Mesh > Sample points).

And I believe you are right, CC automatically detects the angular spans.