CAD files with too many poly and VRED material convert

[abdalabrothers]

Hello everyone,
I'm about to hit my first year as VFX/3D artist and Octane user, so this may be an easy one for many of you.
I've been using Octane/C4D for smaller projects, and so far, no problems.
But our team has received a CAD file of a motorcycle that's going to be released this year, and we're trying to deliver some ideas for a CGI commercial.
The problem here is that the motorcycle is a CAD file with over 25 million polygons and it can't be loaded on the 2080's VRAM, and I'm not beign successful so far trying to optimize the mesh on MeshLab or Houdini (houdini can't even open the FBX file). The model came in a ".VPB" extension and I had to open it on Autodesk VRED and export it as FBX.
The other problem is that the FBX file comes with "Substance Material" from VRED, and the material nodes from Octane doesn't inherit the flakes or other details in the paint, so the material turn into a flat color. And after converting the materials, the colors shift hue (for example, the blue details turn pink).
Maybe I'm missing something here, but as I said, I'm kind of a beginner/self taugh (youtube tutorials only) artist, so many workflow and project managing stuff gets really confusing for me.

[aoktar]

Hi,
you should modify or recreate materials with octane types and textures. There's no perfect way to automatize it. For mesh, is it one part or consist of small parts? What's the problem, any error message?

[abdalabrothers]

About the materials, ok, I though there was a work around it, because there is over 150 materials from the original file.
For the mesh, the file contains more than 4800 parts in it. The problem is that Octane crashes trying to load it, the log say it's out of memory (triangle count:25m can be high, try to decrease polygon count).

[aoktar]

Please post the crash message as text or image. Also where it crashes, in LiveViewer or Picture Viewer?

[abdalabrothers]

I know about the polygon limitation, I'm just searching for answers in the workflow in bigger projects, because I can't find it only.
People remeshing their models, usually remesh simple geometry, such as rocks or photogrametry stuff, so it doesn't work in a detailed model such a motorcycle.
I don't know if this board the right one to post such stuff, to discuss workflow etc.
https://imgur.com/a/KKdBcfP

[aoktar]

You have small amount for FREE VRAM. It can cause a render failure. My advice for solving this:
- Close internet browsers/chrome etc. also AE/Pshop/other 3d programs while working
- Disable the gpu which is connected to monitor cable
- Disable RTX
- Connect some proper small parts of mesh to one bigger mesh

[abdalabrothers]

Followed all steps and it worked, and there is still 800mb~1.1gb of Free VRAM
will try to optimize some of the parts, instead of only 1 big mesh, but for testing this out, it worked just fine!
Thank you !!
https://imgur.com/a/0tFZnxc

[jayroth2020]

I find that you can free up significant resources when you optimize CAD scenes like these. Merging parts, instancing duplicate parts, making sure that you reuse materials as much as possible so as to use VRAM efficiently. I have not seen your file, but I have dealt with enough CAD files over the years to know that the tessellation is usually garbage, so more than likely you can benefit from some retopology/remeshing. I use a combination of Quad Remesher and HB Modeling Toolkit in these situations, and it usually works well. It can be tedious work, but you get really clean meshes (and a much better UV experience, if needed) when you do this. You don't want any wasted polygons in situations like yours. Lastly, use the Octane Object tag for subdivision so you can make a lower resolution retopology mesh.