Reducing an STL - end goal is a stp/iges file

I have an stl that when i convert in FREECAD to stp engs up with a 1.5million face, 4.4gb stp file. THe end goal is to program this to a cnc, so obviously that file is unusable

I am desperately trying to reduce the file without losing detail so I can mill it.

I think i need to use reduce mesh, but I cant seem to find a tutorial. Any help appreciated.

STEP and IGES are support surfaces and curves.
An STL file is a dumb mesh.

The process to using the mesh as 3d reference to remodel and make a surface model is called Reverse Engineering. It can be a time consuming and difficult process.

Since you want to CNC mill it, consider using a CAM application that can generate tool paths directly from the mesh and avoid the entire Reverse Engineering process.

Unfortunately I wish that were an option. A 3d scan was done, reverse engineered. The file was then modified in blender. An stl was exported

I have to get it back to a machineable state. I cant control the project other than to somehow work with the stl i now have.

Is there anything i can do? It is ridiculously organic curved shapes

Can you share the file, or even an image of the file?

If the surfaces are all organic and no sharp edges its possible Geomagic or Powersurfacing/Cyborg (or even T-Splines though its limited with polycount) might work with minimal effort. Hard/sharp edges would increase time and/or complicate the process.

When you say reverse engineered, you mean a CAD file (nurbs surfaces) was created?

I originally recieved an stp file . I believe it was a mistake to modify it in blender as stl. I do have the original stp but it has been heavily modified at this point.

Unfortunately I don’t think there’s an easy method to get this all back to nurbs.

If the hard surfaces, holes, bores, etc. are unchanged from the original CAD file it might be possible convert the surfaces you modified and use the original CAD model for the other surfaces. Of course, the trimming, and/or boolean work might end up being a significant amount of time.

I don’t think this conflicts directly with Rhino so…
As far as your mesh problem, have you you tried Meshlab?

And yes, perhaps you should get the 64 bit version : )

What is the CAM software? 'Cause yeah, it would be much simpler to skip this step.

Hypermill or gibbscam