There is some really good open-source software available to work with 2D vectors. For example QGIS has operations like buffer / clip / dissolve / select by location / join attributes by location... But is there something allowing these operations in 3D?
The closest from what I have tried so far seems to be GRASS. It handles 3D points, 3D lines and... Possibly 3D areas as boundaries? There are 3D faces but from GRASS manual it doesn't seem to be supported by v.select etc. And according to http://grasswiki.osgeo.org/wiki/Help_with_3D the volumes doesn't seem to be supported at all at this moment.
For operations with surfaces (3d areas) raster is proven to be reasonably good alternative and are well supported. But for volumes I even can't find a way how to convert closed face mesh / volume to 3D raster + the processing time and data amount.
Specifically is there any open source tool able to do operation "3d points within volume"? (volume defined by faces in DXF format)
Maybe PostGis or some Python libraries able to load volumes?
But furthermore tool able to do volume overlays, buffers, join attributes by location, clip by plane, clip lines / points / areas by volume etc.?