Mesh

Well, if you already know the connectivity of the mesh (ie. which triangles go between which points) then you just have to calculate vertex normals (easy) and you're done.

If you just have a cloud of points, and you want to make a surface that goes through them - well, that's PhD-level material. As in, I know people who've done PhD projects on this very topic.

I'll see if I can dig up a link. :)

[edit: I'd start here. If you're not keen on reading academic papers and just want source code, try here.]

Do u have the maths to calculate a normal from 3 vertices?

You need a few vector operations. Look for vector subtraction, cross product and normalization.

Given points A, B and C, the answer you're looking for is the normalized result of (B - A) x (C - A)

oops. clicked new thread instead of reply...

Thanx guys. Found Some stuff to calculate the norms.
One question. the new point nx ny nz calculated after the cross product. Does glNormal3f() see that as a vector starting at (0,0,0) going thru (nx,ny,nz)?

Yes.

It should be normalized too, since a 'normal' is by definition a unit vector (I can't remember how, but you can probably tell OpenGL to do the normalization for you).