Importing STEP file

bill_daniels

After an epic catalog search, I found the exact part I needed - a stainless push-type bulkhead elbow for 14mm hard tube and lo, a STEP and IGES CAD files are available for download.  So, I downloaded the ZIP file, extracted the STEP file then imported it into Onshape.  As expected, it appeared as a part tab which opened to reveal a beautiful CAD model of the elbow. I'm feeling good.  Now to import it into my big assembly.

Now the strange thing.  Although the part appears as a tab, it does not appear in the insert dialog box - it simply isn't there.  I went back and imported the IGES file but the same thing - it isn't in the insert dialog box.  What gives?

bill_daniels

As often happens, as soon as I posted this question, I figured it out for myself.  The imported part is surfaces only.  When I clicked on the surfaces icon, there it was.  Consider it answered.

john_mcclary

Many times imports will appear as dumb surfaces. even in Solidworks etc.. when the geometry cannot close the first thing the importers do is leave them as dumb surfaces. The more you import vendor files, the more you may see this phenomenon. I'm glad you were able to solve this yourself within 10 minutes

Perhaps, if Onshape would automatically check the surfaces filter on the insert dialog, it may be more obvious to folks when the part is a bunch of surfaces.

On the other hand... it may prove annoying to those who do not want to see 100 surfaces on the dialogue box just because one vendor's model sucks.

I'm not sure how to make it more apparent when models are imported with surfaces, other than a message or some other visual Que that surfaces have been imported with the model. OR will it be a brief learning forever when people don't see their parts on the import dialogue as expected. 

bill_daniels

I think some vendors provide CAD models as surfaces in an attempt to make reverse engineering difficult.  Surfaces are good enough to see if a part generally fits into an assembly but one often can't do much more with them.

john_mcclary

Sometimes, but other times it come down to a glitch or error during import, usually due to zero length geometry errors or self intersecting parts confusing the importer.