How to do "sub object selection"

Hi all. I am new to Rhino and having some struggle… I want to do sub object selection on a cube, select a piece of a polysurface and then extrude it. In a tutorial it says use Control, Shift and click to select a piece but that is not working for me. Anyone got a tip to help me…?

Hi Johan- Ctrl-Shift select should do it- if you are in shaded mode and you wan to select the face of a cube, Ctrl-Shift click somewhere on the face - otherwise, you can click on an edge, and you will be asked whether you want an edge or one of the faces connected to the edge- you must answer that question (by clicking on an item in the menu that pops up) in order to get the selection. Any luck?


Hi There

I am facing the same situation, and when I click Ctrl-Shift and click, it is not working. I switched to a keyboard and I know is working, and it still didn’t respond to me either. I am right now only using the Rhino 5 Trail version, I wonder if that is what got to it?

Hello - Why V5? can you try the current V6 trial and see if that is any different?


Is it possible to select a surface of a polysurface inside a block, without actually opening up the block?

1 Like

Don’t think so. A block isn’t real geometry, it’s just an instance of a definition stored somewhere. So I guess you either need to edit the block (to change all the instances) or explode it (to change just that instance)…

In the context of commands you can select sub-objects within a block - DupEdge works, for example, but highlighting is almost sure to be missing or incorrect - there is not a way to make selection highlighting work right on blocks, especially when nested… Yet.


Thanks for the info! Hopefully @Pascal’s answer indicate that this will change soon.

I actually asked because I was attempting to measure the distance between a surface I made and a surface on an imported block using your script that you gave me a while ago. :slight_smile:

Edges maybe, other stuff mostly not - for example ExtractSrf with Copy - can’t select anything, any of the solid editing tools like MoveFace, etc. Also with the “Subobjects” selection filter activated, anything like Copy works on the whole block, not even a member of the block and certainly not a sub-object of one of those members…