Complex model made super simple for use in other complex models

I feel dumb but figured I would ask the experts.

Many times I will have 4 or 5 cad models of complex parts such as a camera or laser sensor which have every thing inside as well as outside the part (the guts). I am placing these components inside airframes and creating mounting mechanisms for them. I just need the outside, and the connectors for reference for clearance and the mounting holes for, well, mounting.

Each part I get I want to have in my library so I can import them. But I want these to be as small and take very little horsepower when I import them in. Right now they bog everything down. I could go in and delete all the guts and everything but I figured I was not the first person to have this issue and there must be something to make it small but keep the outside and mounting holes.

I know saving as a block instance helps a lot when dealing with multiples of the same part, but I only use one part each and may have 8 or so hugely complex drawn down to the screw threads models…

What is the right way to handle this?

Thanks so much!

You’ve probably tried this, but if not, Save Small can make a pretty good reduction in file size, and you don’t lose anything critical to the model.

Best regards,

Hi Eric - here is one idea:

For your library, it’s probably a good idea to have a small version of your models that you can swap back-and-forth with detailed ones, as needed. You can name them BlockA and BlockA-light etc.
For the ‘light’ ones, not sure how critical it is to keep them organized by layer/color etc. but in general, I would try:

  1. set your file meshing settings relatively low
  2. use ExtractRenderMesh on your entire model
  3. delete original geometry (leave meshes only)
  4. select all and use Join command to make it into one mesh.

Does that make anything faster? You may need to simplify your models further by gutting them from interior parts you don’t see etc. Also, if needed to keep layers/color, this can be done layer-by-layer and automated with some simple script.
In general what slows down Rhino is not only complexity of the geometry but the number of objects it has to deal with, so making it all into one mesh / few meshes, should do the trick if you need these library items only for reference in your scenes.



Hi Erik

Hehe … sure !
I’m still looking for the best way to do that too …
And I’ll have to remember Jarek’s suggestion about meshes ( Thanks Jarek )

A command that sometimes can help is SelVisible on a shaded view, to quickly separate objects not visible from outside, but you’ll have to run it from different points of view around the object, to select any side of it.

Also, to keep trimmed surfaces as small as possible, ShrinkTrimmedSrf ans maybe sometimes RebuildEdges with a large tolerance.

Rebuild can also help for surfaces with very high CV count, but it takes some time and you may have to retrim trimmed surfaces by hand …

One more thing … as Jarek already said, try to have as few objects as possible joining surfaces into polysurfaces

HTH, cheers

H Eric- I don’t think there is any better way than to go in a spend some time gong through all the unwanted stuff - throw away what you can and simplify where possible the objects you need - like make simplified versions of fasteners, that sort of thing. Maybe remove the inner faces of thin-wall parts (sheetmetal) as well.


Thanks guys! I may have to try the mesh idea. (and the dual parts saving the detail for one and making the other light)

I still struggle with meshes and have not taken the time to learn them more. I just watched the webinar on the new Rhino3DPrint (I already use Rhino-Cam from them) and the interesting thing was with their 3DPrint module there are some really neat looking mesh and point cloud tools that may really help. Or not. 99% of the time Rhino crashes on me is due to RhinoCam. I was confused for a bit and thought they were using native Rhino mesh tools but they are not…Wierd.