Flow Noise tricks and how to.

[anupamd]

Hey guys, im tryint to get noise flowing on a surface based on a curve. I've tried several tricks but I dont think Im getting how it actually works. Righ not Im using tangents to drive the flow parameter but it only seems to be advecting the noise along the borders where the tangents change.

Here is my Hip, take a look and see what Im doing wrong.

flownoise_helper.hip

[Macha]

Ahoy there! Paint some normals and add them to the offset vector!

[anupamd]

Macha, awsome thanks for the help. Amazing how something simple like that can be overlooked.. I thought the offset was more constant for the entire surface, not per pixel. Seems like this works for any sort of noise with a 3d offset. The only thing special about flow is that there seems to be a 4th dimention variable (flow) that creates a nice flowing behavior when animated.

Also on a separate note, particularly you and a few others are very active on odforce and I've learned a lot because of your feedback/help. thank you.

So now that I can advect some noise using vectors, I am wondering how if i wanted to advect texture cordinates using vectors.

My thought is simply to distort the UV cordinates using a vector field. The trick would be to get the 3d world space vector field into UV space..

Is there a simple way to do that without doing a bunch of crazy vector transform math manually?

Thanks!

Edited September 18, 2011 by anupamd

[Macha]

You can distort the noise field directly, no need going via UV's. If you need to "follow" the noise along some uv, then go the other way around: consider the uv the new space for the noise. I haven't tried this, but what happens if you visualize the uv's as vectors? Do they point in the correct directions?