I have Solidworks and Inventor assemblies which I export from these two applications as STEP files.
When I import those STEP files to Rhino, they become nested blocks, which is fantastic.
However, each time the very same STEP file is imported, Rhino automatically creates a new block definition, and a new block instance from it.
And it does this not only for the top most (parent) block, but also for all the nested blocks inside it.
This makes the opportunity of using mechanical software’s assemblies to Rhino nested blocks, practically useless. Because the whole point is to keep the same block definition.
Just to be clear, Rhino makes the same problem with STEP files exported from Rhino, and then imported back to Rhino again.
There is an additional problem it makes by creating a new block around the imported one, but in my case I am not concerned with this, as STEP files come from Solidworks/Inventor and not Rhino.
Here is an example STEP file.
example.STEP (12.4 MB)
I tried exporting both AP203, AP214 from Solidworks, and the result is the same.
I was doing the testing on Rhino 6, Windows version.
@chuck is there any hope this can be fixed, by adding a similar dialog which exists for Rhino blocks: