I want to devolope 4D vision
As our world is 3d in space we develop 3D vision by experience with the help of computers 4D virtual world can be created and 4D vision can be developed.
I have seen some papers and some hyperspace rendering programes but I am not used to them can any body help me in some way or other in this matter

Every answer is wellcomed

This is one of my favorite illustrations

http://upload.wikimedia.org/wikipedia/en/5/55/8-cell-simple.gif

It's an 8-cell (4D version of a cube) rotating in it's 4th dimension.

Needless to say, I don't understand it :)

Pretty cool - although it is certainly hard (impossible?) for us 3-D humans to see how this illustration represents an object whose edges are all fixed at the same length and whose corners are all fixed right angles.

How would one draw a 4-D sphere?

Well, we are really 2D, we have 2 2D inputs from which we infer the 3D world around us. We can assure ourselves of the 3D world through movement and touch. But really we are living off 2D perception.

This is a stereographic projection of a 3-sphere (4D sphere). Keep in mind that it's projected onto 3D space which is then projected onto 2D space.

http://upload.wikimedia.org/wikipedia/commons/d/db/Hypersphere_coord.gif

The red lines are parallels, the blue are meridians and the green are hypermeridians, they intersect at right angles at the yellow points.

Good luck visualising it. I certainly can't. :)