1 如何删除3D物体内部的面,针对格式包括3DS, OBJ等
How to remove internal faces with MeshLab
After starting the filter color->vertex ambient occlusion over the mesh (and after waiting a few seconds) we have computed both a per-vertex gray color and stored for each vertex an attribute with a occlusion value. Side note: MeshLab has a general purpose per vertex and per face scalar quantity that are used and interchanged by many different algorithms with a variety of different semantic; we call this scalar quantity “quality” for no good reason (lazyness), it is ageneric scalar quantity, it could be occlusion value (like in this case), a geodesic distance from border, gaussian curvature.
Second note: Ambient occlusion greatly enhance the perception of 3D shapes! Nowadays everyone recognizes it, but a few years ago not a lot of people was really aware of that (I am a proud user of AO since 2001 for nice renderings of Cultural Heritage stuff 🙂 and, more recently, for nice renderings of molecules ).
Back to the topic of removal of internal faces.
We now can exploit this per-vertex occlusion value to select all the faces that have all their three vertices with a very low occlusion value. That means that we remove all the faces that has no visible vertices. This is not an perfect solution, there are easy counter-examples where this approach could remove visible faces (but with hidden vertices): in most cases it works wells but a bit of caution is always recommended.