Simple Edit to Imported STL File

[Anonymous]

I've read around that's it's tough to edit STL files imported from thingiverse and such. All I'm trying to do is just add threads inside one cylinder. Is this a reasonable endeavor or should I just design the thing from scratch?

[Anonymous]

Hi Bill, you should be able to do that without much trouble.  Below are two examples I did with an imported stl.  After importing, while still in Create Base Feature mode, you go to Modify > Mesh > Mesh to Brep (the max faces is 10,000, so if your part has multiple pieces, try to import each as separate stl, using a program like Meshmixer to split up an assembly...that way can achieve best quality stl surface via maximizing possible number of faces).  What I did then, out of Base Feature mode, was extruded an insert that I threaded, then used that to split the Brep body so the insert could go into the resulting hole. 

Let us know if you need any more help!  The possibilities really seem endless 😉  Here is the .f3d file you can download, then upload into Fusion 360 to view the timeline for reference.

https://drive.google.com/file/d/0B3hl1g1DsQouSVY2UnpudktUME0/view?usp=sharing

and the zipped version

https://drive.google.com/file/d/0B3hl1g1DsQouWXFaeXIxLVhXSzA/view?usp=sharing

Jesse

[jeff_strater]

Thanks, Jesse.  That workflow is great for "organic" shapes (I love the foot with a threaded hole through it...), but I would be cautious.  The Mesh->Brep path can make performance pretty bad.  What this does is to convert each mesh face into a Solid or Surface face.  This can result in some pretty undesirable behaviors (cylinders are not really cylinders after this conversion, etc).  If your part is a fairly simple shape, with lots of analytic geometry (planes, cylinders, etc), you might be better off just reverse-engineering the part.  So, import the STL mesh, then design around it to get as close as possible the same shape using native Fusion features.

Another option, depending on your mesh, is to convert it to a TSpline.  This really only works well for meshes which are composed primarily of "quads" (four-sided facets), but if your  mesh is of that type, and is pretty "organic" shaped, the result is pretty good.

Right now, Fusion has only limited support for meshes.  We'd love to expand that to allow more editing capabilities, but the customer demand for that has not been very high so far.

Jeff Strater (Fusion development)

[Anonymous]

Thanks Jesse-seeing the timeline was very helpful. What I'm importing is definitely not ideal for TSplines. The cylinder is already there, I just need to add threads on the inside. I tried making a cylinder seperately and adding it like Jesse did; but indeed when I zoom in very closely, I see there are gaps between the cylinder I added and the cylinder that was there.
What does Mesh to Brep do exactly?

[Anonymous]

Mesh to Brep takes in imported mesh and converts it to a body that can be edited in Fusion.  As Jeff said in general it is much better to work directly with CAD file formats, such as Fusion's native .f3d, or .step, .sldprt etc.  Another good idea Jeff mentioned is to import your stl mesh and just use it as a reference for dimensions to make your CAD model in Fusion.  If all you need is a cylinder, and then put threads in it, that is very straightforward. 

Let us know if you have any more questions!

Jesse

[Anonymous]

Thank you so much for this explanation, It worked!