Can't combine imported stl and body.

[Anonymous]

I am really getting a hard time combining a mesh into an extruded sketch. Any solution how to do it ? 

[PhilProcarioJr]

@Anonymous

We need some more info.

First you can't combine a raw .stl file and a body. It has to be converted to a B-rep first.

Second it looks as though you have a bunch of bodies and only one component and the master, that's going to cause you problems sooner or later.

Third can you hide everything but the two objects your trying to combine and expose the entire tree and take a screen cap?

[TrippyLighting]

You cannot directly combine a mesh with a solid body. the mesh first has to be converted into a solid body.

A pre-requisiet for the conversion of a mesh to result in a solid body is that the mesh ecloses a volume "watertight", without holes.

That is not the case with the mesh you imported, which is the reason why that mesh converted into a open surface body indicated by the orange symbol in the browser.

I have never tried what I am going to suggest, so this may not work at all, however, what you could try is to use Split Body and use the open surface as the tool.

In general, however, surfaces created from .stl meshes use this way are going to result in very bad surfaces in your model.

Garbage in equals garbage out 😉

I don't at all mean to offend, however, the real CAD world usually deals with mathematically precise surfaces, be those NURBS, T-Splines or Solids. In that realm .stl meshes are, in fact garbage.

[weshowe]

Oh. c'mon... .stl files are a manufacturable representation of a more precise idea. No matter how precise you model stuff, it ends up in a less precise state when it is made manufacturable. All the nicest spline surfaces you can design will eventually be a (finely) stepped approximation of that curve.

Now the biggest issue I see here is that Fusion was not made to start with approximations and turn them into precise models, but rather the opposite. Drawing a knob from a sphere with the form tools, adding a threaded hole and exporting the resultant shape to an .stl file and 3D printing that work wonderfully well with Fusion.

Managing previously-triangulated surfaces is not hard with the right tools, but Fusion is not that tool. Sticking with Autodesk for examples, since they are our host here, are 3DS Max, Maya or Softimage, all of which will manipulate those quad and triangulated surfaces easily in many ways, including soft manipulation methods.

If all you have is a hammer, every problem looks like a nail.

 - Wes

[TrippyLighting]

That really depends on what sort of editing you want to do. I've got a good bit of experience with subivision surface modeling and modifying .stl files that represent hard surface models such as in this case is a bear, let alone with some CAD precision. You would likely not use proportional (soft) editing to edit this model. That is more aimed at organic shapes.

But looking at the screenshot again, that might not even be of interest. The block is likely a Fusion solid,but the cameara does not look like it was created from an imported mesh but originates from a surface model, possibly .iges or .stp. I've seen enough .stl imp[orted into Fusion 360 and they look different.

The imported geometry was converted into an open surface model, so there are two ways to possibly deal with that. the OP can try what I suggested in my last post, with split body, or possibly this open surface model can be converted into a solid body by capping open holes and stiching the surfaces in patch mode. That will then allow to use the "Modify -> combine" tool.