Hi all. I’ve recently become aware that the popular OnShape CAD like free 3d software does not play well with stl (mesh?) files… You can import them and view them, but you can’t join or assemble them in anyway since they are not real solids I guess.
I know it’s outside the scope of this software, but if there was any way to be able to export files in some kind of a non-mesh, solid model, it would be super helpful for doing external fitment of large shapes and complex assemblies.
This would be a nice feature to have, but it’s important to understand why it won’t happen soon. OnShape and other parametric CAD tools struggle with mesh files because there’s no such thing as a mesh file with parametric data. Even slicers that import STEP files discard parametric info since mesh formats don’t support it.
You might ask, why not store the parametric data elsewhere? For simple shapes like cubes, that’s possible. But with curves, it’s much harder, which is why CAD companies hire experts to create proprietary algorithms for ‘best fit’ modeling. Fusion 360 calls it prismatic modeling, and it costs $800 a year. SolidWorks and SolidEdge offer similar, more expensive tools. After 30 years of searching, I’ve yet to find a free, easy tool that handles curves well.
This challenge dates back to the late '80s when people tried converting PostScript files (which use math for curves) and found converting pixel images like GIFs or JPEGs to PostScript was impossible. Many have tried to solve this issue, but none have fully succeeded. If I’d cracked this, I’d have been a wealthy man indeed.
