CAD conversion to polygon modelling


#1

Hi, I don’t know if this is the correct subforum for this, but I’ll try.

I’m looking for a reliable way to convert CAD-files so the models are usable in polygon modelling software (i.e Maya). What I mostly need is a way to extract the main geometric outlines so that these can be used in a polygon modelling workflow. It can be nurbs or orthographic vector graphics or something else. If it’s somehow possible to convert the CAD-model to a complete usable polygon mesh it would be even better!

I’ve done some experimenting with importing CAD-models directly into Maya, but find that this isn’t usable. Either they consist of thousands of small triangles that break up the model outlines, or the model has other properties which makes it unfit to use. Since I mostly do hard surface modelling it’s important that I can keep the model outlines. I basically need a good starting representation of the object, so I can work on it for changes, texturing and other visual effects.

What programs and/or techniques are out there to accomplish this?


#2

CAD models always come in messy, there is some mitigation you can do, otherwise generally you have to rebuild the mesh.

  • 3dsmax has a plugin called Sini Software. Unfortunately I dont think its available for Maya but if you have this tool inhouse then can be used to quickly clean wild vertices, collapse meshes, combine overlapping areas etc. Not perfect depending on the geometry but works in C++ so its very fast.
  • Clean the geometry in the CAD software before importing (if you dont know the UI this will be a learning experience but usually much faster way of cleaning geometry in the source software).
  • Ignore it and import it as is (untick any extra things Maya may be doing like recalculating normals, welding etc). At this point you can just rebuild the areas that look terrible towards the camera view…

Unfortunately after 10+ years of working with CAD, Revit & Sketchup models these rarely come in clean. I find building a pipeline around common issues will be your best bet and finding/using plugins that mitigate some of the major issues.