doc Posted June 4, 2011 Share Posted June 4, 2011 Hi, I want to modify the density of my fog volume using noise. but what I'd like to do is have the noise stretch and contract(in an art directable fashion) in different parts of the volume. In the attached file I've put together an example of how I would do this on regular geometry. I applied uv's to distorted geometry and then use those uvs to control the noise space on the undeformed geometry. I was wondering if something similar could be done with a fog volume. thanks noise_stretch.hip Quote Link to comment Share on other sites More sharing options...
ikarus Posted June 4, 2011 Share Posted June 4, 2011 you can just add noise to the position input of whatever noise function you're using to generate the density alternatively plug noise into frequency with low turbulence and large frequency, experiment with noises volnoise.hip Quote Link to comment Share on other sites More sharing options...
brianburke Posted June 5, 2011 Share Posted June 5, 2011 hi doc. you can build your own coordinate system to index noise from in a volume (in the same way as you are using the 2d coordinate system of 'uvs' to index your noise in your surface version). here's an example of building a coordinate system using a uniformly spaced grid and pushing it around with the magnet sop. when you index the noise from this coordinate system, it appears that the magnet is deforming the noise itself. kinda interesting... here's a flipbook: noisevol.mov good luck volnoise_deformed_coords.hipnc Quote Link to comment Share on other sites More sharing options...
tjeeds Posted June 6, 2011 Share Posted June 6, 2011 Ha! This is great Brian, just out of curiosity did Jonathan have a hand in coming up with this? Quote Link to comment Share on other sites More sharing options...
ikarus Posted June 6, 2011 Share Posted June 6, 2011 fantastic solution! Quote Link to comment Share on other sites More sharing options...
brianburke Posted June 6, 2011 Share Posted June 6, 2011 Ha! This is great Brian, just out of curiosity did Jonathan have a hand in coming up with this? who? Quote Link to comment Share on other sites More sharing options...
Macha Posted June 6, 2011 Share Posted June 6, 2011 (edited) Here is my attempt. It seems very similar to Brian's idea, perhaps somewhat less controllable, but volume preserving. Again, I have problems with the falloff. I'd be happy if somebody could shed some light on that. (Volumes don't falloff linearly it seems. The default volume shaders have some setup with an exp I think, so something's going on there ) I suppose you could use something like that to grow clouds where large volumes become more defined over time. scalevolume.hip Edited June 6, 2011 by Macha Quote Link to comment Share on other sites More sharing options...
tjeeds Posted June 6, 2011 Share Posted June 6, 2011 who? Vaughn, he was always pretty crafty with volumes. I take it that's a no Quote Link to comment Share on other sites More sharing options...
brianburke Posted June 6, 2011 Share Posted June 6, 2011 Vaughn, he was always pretty crafty with volumes. I take it that's a no ah, that dude does know his stuff for sure :-) Quote Link to comment Share on other sites More sharing options...
doc Posted June 7, 2011 Author Share Posted June 7, 2011 many thanks for the help, this helps a lot. doc Quote Link to comment Share on other sites More sharing options...
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