Convert a point cloud from a 3 D scanner to OBST

[finn.dr...@gmail.com]

Has anyone tried to convert a point cloud from a 3 D scanner (PLY format) to OBST. If yes – I would be happy to get some help/advice how to do this. My “cloud” is a mine, and it has a complex geometry. The file is about 1GB. The size of the mine is 65x32x12m

[fde]

If you could convert it to STL, you can import to Pyrosim. Then it can be converted into OBST.

[sterling baldwin]

Are there any open source alternatives to Pyrosim? Im also in the boat of needing to construct a OBST mesh from a set of points, but need a programmatic solution since I have many meshes for many input files, so a one-off manual solution wont work.

[Randy McDermott]

BlenderFDS is open source with a fully programmable python interface.

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[Emanuele Gissi]

Same as qgis2fds, Blender has an incredibly effective Python api. And you can programmatically reuse BlenderFDS datastructures. SO that you do not start from scratch.

In my todo list i have had for a long time the nececessity of writing a wiki page on scripting. This could be the right occasion to do that.

Let me know.

[Dave Sheppard]

I have the same question as the original post.  3D scanners create 3D point cloud files, which are files consisting of X,Y,Z coordinates where the scanner measured obstructions. There are often millions of coordinates in each file. 

To use 3D point clouds files in pyrosim (or another FDS input builder) the 3D coordinates must be converted to a format with meshes, or faces, or obstructions.  Does anyone know of products can can perform this conversion?

[Kevin McGrattan]

If you can "read" the 3D points, you could then just write a simple script in whatever language you choose to create an OBST line for each cell that you deem "filled". We have been dabbling recently with reading 3D tree and vegetation data, but I'll let others who know more chime in.

[Emanuele Gissi]

Currently, this is how I would it:

1) Transform your point cloud to a mesh (3d surface, not FDS MESH)  in Meshlab. See some guidance here:

https://fabacademy.org/2019/docs/FabAcademy-Tutorials/week05_3dscanning_and_printing/point_cloud_mesh.html

2) Import the resulting *.obj or *.stl file to BlenderFDS

3) Set the newly created Blender Object as a voxelized OBST or as a GEOM (beware, the latter is an unsupported experimental FDS feature)

4)  Export to FDS

This procedure uses fully free and open source tools.

If you can share the point cloud I can take a look. I wish I could write a wiki page on that on BlenderFDS website.