Ok so for years my team has been having issues bringing in structurally correct objects from CAD into C4D - the mesh is heavy, messy, difficult to work with, long render times and sometimes issues when rendering with transparent materials.

I asked a lot of people for help on Twitter after searching the forums and I've finally found a solution which only came up once within everyones answers - so hopefully this will help any others who may be having this issue.

The software is called MoI, and I just downloaded the trial version to have a look and see if it could solve my issue, which it really really did!

Right so this is the pipeline that worked best for me..

  • Open up MoI, go to the bottom left corner, click 'File', 'Import' and import your CAD data as an .igs file.
  • Over on your right hand side, click 'View' and 'Reset all', which just centres your model in all viewports.
  • Click and drag over all your model to select all and it will turn yellow once selected.
  • Go back to the 'File' button and click 'Export'. If you choose to export as an .obj an additional window will come up which allows you to select how many polygons you want, what kind of tessellation used from n-gone to triangles etc, and if you do want larger areas with less polys and smaller more detailed areas with more polys. As you change your options, you can also view the mesh that will be exported update in real time in your four-view.
  • The best that worked for me was the highest amount of polygons, and weld vertices along edges ticked (so any vertices along the same edge will merge together, which hopefully should give you an even cleaner mesh), and that was it!
  • Import this .obj into C4D and it should be split up into several objects automatically. Just take a few minutes and select the faces of each part of the import, as a couple of the objects may need their normals inverted. I'm not sure why this happens or how to solve it any other way than just working through and double checking if any need inverting in Cinema.
  • Once all normals are facing the correct ways, group the objects together and there is your mesh, ready to texture and render.

Just to give you an idea of numbers, when I was experimenting with glass bottles, the original CAD data, brought into Cinema had 1,539,326 polys and the close up took 17:12 minutes to render; my high rez .obj had 76,747 polys and took 12:17 minutes to render; and the lowest resolution export had 17,747 polys and took even less time to render (although with the low rez options some of the smooth edges are coming through slightly faceted).

Let me know what you think, or if anyone has tried any other ways to solve this issue.

Hope this helps!

Frankie x

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