How to delete all faces/geometry that isn't visible? Lowering poly count for unity? Ok, Ive looked at Removing internal geometry before 3D printing but am really trying to reduce poly count for export to UNITY especially. Ive decimated and done limited dissolve, but really I still have high poly count owing to internal geometry that is not seen, but augments poly count regardless:



I just need the "shell" essentially for export to unity. I tried ctrl-alt-shift-M, but Im not sure what this selected, and didn't get much. Select-interior faces does nothing.

How can I get rid of unseen geometry?
Box selection
Go into edit mode ↹ Tab.
Switch to solid view mode (toggle Z).
Switch to face selection ⎈ Ctrl↹ Tab &gt; F.
Box select the faces. B + drag +  LMB confirm
You have now selected the exterior faces.
Invert the selection. ⎈ CtrlI
You have now selected the interior faces.
Delete the faces ⎈ CtrlX &gt; Faces.