Removing unnecessary polygons

I have two questions regarding removing and reducing polygons:

  1. Is there a way to reduce the number of polygons/triangles by specifying an angle? I have found the function that can reduce the number of polygons to say 50%, but I would like to be able to combine polygons that has an angle of say 180 (+/-5) degrees, considering them to be flat. Is there a way? Is there a script?

  2. Is there any script out there that can remove hidden surfaces? Let’s say I create a cube and inside the cube is a number of polygons that can not be seen (assuming nothing is transparent, and that the camera is outside the cube). Is there a script that can find such hidden polygons and remove them?

Thanks!

As far as I know, the best Blender has to offer to reduce polygons is the decimate modifier:
http://wiki.blender.org/index.php/Doc:Manual/Modifiers/Mesh/Decimate
Not really what you were asking for, but a really great tool.

I don’t know of any “find hidden geometry” script, but you can

  • Ctrl+Shift+Alt+M in edit mode to select disconnected verts and edges
  • enable the “Occlude background geometry” button below your 3D view to make it easier to select only faces pointing outwards
  • use the L key in edit mode to select linked geometry (Ctrl+I to reverse the selection)

Good tips! Thank you!