Macha Posted June 23, 2011 Share Posted June 23, 2011 I'm looking for a way to ramp the density of a volume in a controlable and smooth way. Say you have a cloud of arbitrary shape. I want to increase the density as we get closer into the center of the cloud. There are 2 problems with this: 1) How do I find the (local) center of a cloud? I have done something similar here: The particles in that video travel to the nearest central part of the object. However, that method is unsuitable for my purpose because it needs to run a pop to find the center. 2) How do I ramp a volume in a visually pleasing way? I always get either-superdense or super-weak results. So, the density ramps in a non-linear way. Looking at the default volume shaders it looks like it is something exponetial. So far what I have done is to create a point cloud and blend an attribute from the surface of the volume. I create a field out of those attributes and use it multiply density. But as I said there are those 2 problems with. I tend to get volumes with a very visible and sudden increase in density, wheras I want a smooth one. Makes sense? Quote Link to comment Share on other sites More sharing options...
sam.h Posted June 23, 2011 Share Posted June 23, 2011 Why don't you use an SDF? you can make one with iso offset and then remap the values with a volume vop? I can post an example file if you like? You won't really ever get a 'linear' ramp (in screen) out of a volume... although you can get a more pleasing one by powering the density ... Quote Link to comment Share on other sites More sharing options...
Macha Posted June 23, 2011 Author Share Posted June 23, 2011 Yeah...hmm...I think that might just solve those 2 problems. Quote Link to comment Share on other sites More sharing options...
Adam Ferestad Posted June 26, 2011 Share Posted June 26, 2011 I would like to see that actually Sam. I am getting ready to try some stuff with volumes, and I can say that it feels a little daunting to me right now. Quote Link to comment Share on other sites More sharing options...
sam.h Posted June 26, 2011 Share Posted June 26, 2011 Attached a file. So, inside the volume are negative values (distance to the surface) and outside is positive, the volume vop just fits those values to get a gradient... sdfToVol.hipnc Quote Link to comment Share on other sites More sharing options...
Jason Posted June 27, 2011 Share Posted June 27, 2011 Perhaps blur the clouds and use that blurred volume to ramp in? (Adding it, or whatever other method you prefer) Quote Link to comment Share on other sites More sharing options...
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