Wowee! Many thanks - and a question
I use GH/Rhino to design parts for 3D printing. Many of my designs have “overlapping shells” which in effect are the combination of intersecting Breps. Designs like this are a problem because, for 3D printing, you have to export the final geometry from Rhino as an STL file, and STL files don’t accommodate overlapping shells very well. Actually, not at all.
Here’s an example of apart I’m currently ready to print:
As an exported STL file (or mesh for that matter) this part cannot be printed because the slicing program that generates the printer’s control code misinterprets the overlapping shell geometry and produces bad results. So, to fix this, it is necessary to run the STL file generated by Rhino through a “fix it” program. Fortunately, there are a couple of these that are readily available and the almost always work ok.
But having to do that is annoying and time consuming, and would not be needed of the problems of overlapping shells could be eliminated before creating the STL file. I’ve tried various ways to do this, but none of them worked.
Until now. By simply adding 3 mesh related operations to my final Brep function I get a result that no longer has overlapping shells and whose STL file I can process with no problems:
The SDiff creates the final geometry I want to print - the image shown above - and the 3 mesh functions eliminate the overlapping shells and produce only the “outside” of the part which is exactly what’s needed for 3D printing. The comments by Ethan, Nicolas, and Peter made it clear to me that this is what I should have been doing all along. This simple method will save me a lot of time and CPU cycles - so thanks to everyone for pointing it out.
My question is also simple: why, when I select any of the first three GH components shown above, does my display look like the first image, but when I select the 4th one, it looks like this:
That is the object I bake and export and it produces good results, but on screen it looks - weird. Since it is the final result that counts I’m not all that concerned about this, but it would be nice if the final result looked like the final result.