I'm new in quaternions. The problem is, that I wrote a quaternion fractal generator program, and I don't know, how to shade the 3D image, i can't calculate the surface normals. Please tell me some algorithm, on how to do this. Thank You.

-- Nagy Imre (nagyimre@xnet.ro), October 05, 2002

Answers

Hello Nagy:

I've been playing with quaternions for about five years now, and it is quite fun :-) I am going to encourage you to generate a different kind of image altogether.

What does a quaternion represent? This is not a trivial question. In fact, it is probably the reason quaternions are not studied widely. People could not describe a picture in four dimensions.

I think a quaternion represents an event, a bit of information that something happened at this x, y, z place at time t. If your fractal generator produces 100 quaternions, that is 100 events that could be the basis of an animation. I have software now that would take a 100 events and make an animation. So far, I have made an animation of constant inertia (URL at the end). The animation requires Adobe's SVGViewer which can be freely downloaded. My software to generate the SVG file also can be downloaded.

If your heart is really set on static 3D images, you will need to get help from someone else because I don't think that is really an accurate representation of what quaternions are about. If you sent your code, I could create a few SVG files and put them up on a site. Or you could send a few lists of quaternion fractals, and I would input that into my SVG file generator. Tell me which option you would prefer.

doug

QEMation project: http://theworld.com/~sweetser/quaternions/qemation/qemation.html eq2svg tarball: go to qemation page, shift click on "eq2svg.tar.gz" link adobe SVG Viewer: http://www.adobe.com/svg/viewer/install/main.html constant inertia page: http://theworld.com/~sweetser/quaternions/qemation/inertia/inertia.html

-- Doug Sweetser (sweetser@TheWorld.com), October 05, 2002.

good fractal thread. Thank You for this nice. Euer Kaesebleich

-- marcus marbar (kaesebleig@gmx.net), February 03, 2004.