Volumes 101: Volume Gradient
Added 2017-09-21 06:50:48 +0000 UTCThis is the beginning of a multi-part tutorial in which we'll build the setup used in most of our title cards for the Volumes 101 course.
We'll start by exploring two simple yet powerful tools here: The volume gradient and VDB advection.
Let's start by going over what a volume gradient ist, how it can be generated and why it is so useful.
Comments
nice, I was trying to do something similar and my mistake was using merge instead of vdb combine
Ahmad Q
2022-04-09 22:25:52 +0000 UTCTry connecting the platonic>vdbfromPoly into the 2 input of the Solver. Then use a VDB SDF Union set to SDF intersection after the VDB Advect.
Justin Kirk
2021-11-02 16:28:20 +0000 UTCI was trying to figure out how to get the tetra to be a cage for the volume so it holds them all in but I'm a bit at a loss, any tips there?
Lukasz Pason
2021-09-16 16:08:14 +0000 UTCHi nouhad, did you check your setup against the provided scene file? Does that scene file work for you? If so, please check if you can spot anything you might have set up differently. If that doesn't solve it please let us know :) Cheers, Mo
Entagma
2019-04-04 13:03:43 +0000 UTC@Entagma Hi there, does anyone know why the SOP errors out and says "Missing velocity grid" ? I thought it's because I didn't add a switch to Input 1 and do a condition to check for $F==1 but it still doesn't work.. any feedback would be greatly appreciated
nouhad
2019-04-03 08:17:11 +0000 UTC<a href="https://www.instagram.com/p/BpYABeHDxbV/?utm_source=ig_web_copy_link" rel="nofollow noopener" target="_blank">https://www.instagram.com/p/BpYABeHDxbV/?utm_source=ig_web_copy_link</a>
André Gama
2018-10-26 18:52:42 +0000 UTCCan anyone explain roughly why the 2 spheres don't penetrate initially, then eventually they do penetrate (when looking at the volume slice before adding the smoothing)?
Clinton Chang
2018-07-07 05:35:34 +0000 UTCYes it is :) Cheers, Mo
Entagma
2018-04-16 16:33:12 +0000 UTCcan't understand why the sphere would inflate, the gradient vector is outwards?
wang
2018-04-16 15:23:52 +0000 UTCCool
Saman Fani
2017-12-06 10:15:50 +0000 UTCThat's really interesting. I was wondering how would you do if your inout source volume was a moving one. For exemple A Vdb from particles Source. Would it be possible to use to Vdb Advect node ? Thanks
Orson favrel
2017-10-03 01:22:00 +0000 UTCexcited to learn about integrating geometry collisions with this setup. So powerful and adaptable!
Samm Hodges
2017-09-28 04:05:25 +0000 UTCIt's a really great technique, opens up all kinds of possibilities! Can't wait to see how you apply the gradients to the fog volumes.
paul silcox
2017-09-25 20:37:30 +0000 UTCCool! Sounds really great. I am looking forward to the tutorials already then :-)
Dag Kjetsa
2017-09-23 17:48:32 +0000 UTCJust checked - you'll be able to use the exact same techniques that we'll be using in our upcoming tuts on your fog VDBs as well without heavy modification :)
Entagma
2017-09-21 15:58:41 +0000 UTCWow! That would be amazing if that would be possible :-)
Dag Kjetsa
2017-09-21 14:35:56 +0000 UTCOk, understood - thx for the clarification. I'd suggest to try and adapt the techniques we're gonna show in the upcoming tuts for fog volumes, they seem pretty close. Yet I'll think about if it makes sense to do a specific tut about that topic. Thanks :)
Entagma
2017-09-21 10:46:39 +0000 UTCOh, cheers for the fast feedback! :) In my specific case I am looking for good, fast ways to have control over the density levels within a cloud. Gradients according to the bounding box and via the use of other volumes (as masks) to control for example mixing of looks I have sort of figured out, but it would be super helpful be able to control density levels according to the gradient within such an object that has a complex structure. And also to be able to more precisely control where to apply more advection, or where to add/create finer details, like tendrils and "whispyness". Again thank you so much for these tutorials!
Dag Kjetsa
2017-09-21 10:32:14 +0000 UTCThanks :) For directional control of SDFs - that's gonna be the topic of the next tutorials. What would you like to achieve by controlling a fog vdb with a gradient?
Entagma
2017-09-21 09:58:39 +0000 UTCAwesome! This is precisely the kind of stuff I have been looking for. Finding information about how to deal with, and properly use the volume gradient and volume sample together seems somehow hard to find, so this is gold to me. If anyone could tell me if/how it is possible to use these tools and principles to control densities in a fog vdb ( inside/out directional control)... :)
Dag Kjetsa
2017-09-21 09:12:41 +0000 UTC
