creating a mold or shell of another object

edit: and 1 minute after posting…
I wasn’t doing the occlusion stuff right. You still can’t select all, but if you enable occlusion culling, then do border select, then change your view and shift-border select, you can get all of the external faces, then invert selection. Not a one-step solution, but SO much easier than individual selection/deselection.

Hello board,

I’m creating what could be described as tunnels out of the default blender cube mesh. I duplicate them, move them, then snap them to the grid. Once I have the whole thing constructed, there might be 40-50 cubes for each design. I create two models out of this: one exactly as is - not joined or anything, and another without any interior “walls”. What I’ve been doing is joining the cubes, selecting ALL faces, then deselecting all of the faces facing outwards, and finally deleting what’s left.

Did I mention that I have about 60 of these constructs? I need a better way to get a mold of the cubes (It’s used in a game for collision detection to ensure that while a player can pass through the interior walls they can’t fall out into open space.)

I tried doing a boolean difference, but it deletes the space the cubes occupied and leaves the walls! I don’t want any space between the cubes, I can’t have these interior faces… how can I do this in as few steps as possible? It needs to be done after the modelling is finished, so that I can have the two distinct models.

(Alternatively, if anyone knows a way to auto-select only visible faces that would be perfect. Occlusion does not seem to be it.)

I hope someone can point me in the right direction… I’m having a hard time even describing what I need so google has been useless to me.

Alternately you can just use the “L” button to select all of the verticies linked to what your mouse is hovering over. If your mesh is connected, then what you’re doing is probably the fastest way.