CGTalk - Noisy Channel?

Nonproductive

02-15-2003, 02:31 AM

Ok...here's a question for all you Math folks:

Lightwave has something called "channel modifiers." Essentially what these do is modify the function curve for a particular channel in some way. One of my favorites is "Noisy Channel."

Noisy channel adds a sort of perlin noise (http://students.vassar.edu/mazucker/code/perlin-noise-math-faq.html) to the function curve. I have a screenshot if anyone needs to see it to understand, but no place to host it currently to put it here. This is great for randomly swaying a tree in the breeze or adding a slight oscilation to a hovering robot.

So..given Hash's expressions (http://www.hash.com/am2003/Expressions/Index.htm)...how would I duplicate a 2d perlin noise function (math is in the perlin link above) so that I could, for example, apply it to a null and then use that null additvely with the channel for the model? Or should I just ask for Hash to add a perlin noise expression?

thanks in advance!

John Keates

02-15-2003, 11:54 AM

I have been thinking about this also. There is nothing to loose in asking hash for it. An alternative might be the following...

Make bone rig with, say, 4 bones in a chain. Make the first largest and progress smaller as you go. Make each of the bones rotate at different speeds. Maybe the large bone rotates slowly and the small goes fast. Use the position of the last bone to controll the null. You should get a fairly random looking effect with all the bone motion adding in pseudo random ways with a lot of controll (if I am right). I havn't tried this though. I would be interested to see if you try it and it works.

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