Hi, I’ve written this function to be able to export OBJs directly from GHPython inside Grasshopper. So far everything works fine, however dense meshes take quite some time to export. I’m thus looking for ways to optimise the code! import os def export_obj(mesh, path, filename): obj_fname…

I don’t know how this could be done efficiently in the context of Grasshopper.

[image] stevebaer: I don’t know how this could be done efficiently in the context of Grasshopper. Not with Grasshopper. I mean GH will run the PyPy or Cython and the conversion will happen using RhinoIO.dll or Rhino3dm module. You can skip GH all together. Just have that mesh saved as 3dm

How are you getting the mesh from Grasshopper to these external python environments? That is what isn’t making sense to me.

[image] stevebaer: How are you getting the mesh from Grasshopper to these external python environments? subprocess.call()? System.Diagnostics.Process.Start()? (in dotnet context) I just recently found out about Cython (yesterday) I don’t know the syntax yet.

I re-balanced the parallel tasks and improved the binary writes to reduced the export time to 13.4 sec for my 18.4M faces test case. The progression of improvements, measured in million of mesh faces per sec, now looks like this: (1) 1.37M/sec with latest parallelPython/DLL script (= 5.1X Rhino Im…

What does your current c++ implementation look like? Maybe it would give me some ideas to improve the C# implementation. Honestly, I didn’t really spend much time attempting different optimizations as I figured the sample I gave was good enough.

Steve, Right now the script is a bit torn up as I am still playing with adding more parallelism. Edit: I posted the final version in my later post below. I borrowed the core of the parallel code from an GH posting on the forum that does this: # Size pieces input and results output lists for 10 e…

Steve, Here are my Python script and DLL for quickly exporting a mesh to an .obj file using parallel tasks (1.37M faces/sec or 5.1X faster than Rhino Export). Edit: These were updated 8/27/2019 to correct an indexing error. ExportObj_with_DLL_for_Steve.py (15.3 KB) Mesh2String.dll …

Steve, An observation here on some of Rhino’s built-in methods for working with meshes. The methods for extracting the mesh data vary widely in performance. While the .ToFloatArray methods for vertices, textures and normals are very quick, 0.2 sec for the 27M X,Y,Z components of the vertices in a…

[image] Terry_Chappell: The 20X slowdown for the .ToIntArray method does not make sense. Perhaps it was created by a different McNeel software developer at an earlier time compared to the fantastically fast .ToFloatArray methods? :slight_smile: I can fix this

How to optimise GHPython OBJ export?

Grasshopper

brian (Brian Gillespie) August 27, 2019, 10:17pm 83

RH-54455 is fixed in the latest Service Release Candidate

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How to optimise GHPython OBJ export?

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