cannot add threads to an stl: "there was a problem combining geometry"

[Anonymous]

Hi,

this is the first time trying fusion 360. I'm used to simple parametric modelling such as solvespace,

but that can't import an exiting STL.

I need to add threaded holes to an existing model someone else made.  I did:

1. insert->mesh

2. do not capture design history (to get mesh options)

3.  solid->modify->convert mesh to brep

4. create sketch on bottom, add circles, extrude circles to holes

5. create->thread

but it wont let me create the threads

this troubleshoot only suggests doing validate, but that finds no errors

https://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/Una...

[TrippyLighting]

Fusion 360 and CAD Software in general does not work well, with triangulated meshes (.stl data). 

[TheCADWhisperer]

@Anonymous 

See Attached file...