Dear all, I am looking for an interactive software that can let me play with 3d geometry. I apologize, as I am not sure of the right technical term of the sorts of shapes I am interested to work with. I am not a mathematician or physicist, but rather use these as philosophical metaphors and illustrations. I think that what I need is called either differential geometry or topology. You can see examples of what I mean here http://www.dreamstime.com/stock-photo-worm-hole-image15885270 Basically, I need to be able to draw a plane in 3d space and then add singularity points to crate this vortex shape, or gravitational pull and change from 1 bifurcation point to 2, etc. Does this makes sense? The closest thing I found is this software http://raumgeometrie.de/drupal/ and I was wondering if you might know others, preferably open source. GeoGebra is a good example of another useful software that does not require technical knowledge, but it's only for 2d shapes (the beta does 3d, but nothing like I need). Thank you very much!