deleting/killing particles by bounding box, but with threshold and/or falloff
12384 23 2- druitre
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- Enivob
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Particle deletion is a boolean state. You can't have something partially deleted. The particle either exists or it does not. So falloff is irrelevant. You may want to look into scaling a particle to 0 to implement some kind of falloff.
Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
- patar
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- old_school
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But you could have an attribute that accumulates over time based on the density of the volume. Then cull when that accumulated attribute reaches 1. Is that kinda what delete by volume node does in Soft?
Does the attached file do what you want? I created a couple POP wrangle nodes that can be wrapped up in to an HDA if you wish.
Does the attached file do what you want? I created a couple POP wrangle nodes that can be wrapped up in to an HDA if you wish.
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Just saw your post with the ramp weight snapshot in Softimage. Yes you can add a ramp parameter to the density accumulator scalar as well. I just set it to 0.1 I think.
Nothing stopping you from querying the density from the volume and using a transfer function (ramp) fed by a fit01() to remap the accumulator multiplier.
I chose to use a blur on the volume itself to set the volume weight blur. It's the most lightweight method and done all the time to have volumes as masks. Lots of volume tools to modify the weights as well.
Nice to have Houdini support volumes natively.
Nothing stopping you from querying the density from the volume and using a transfer function (ramp) fed by a fit01() to remap the accumulator multiplier.
I chose to use a blur on the volume itself to set the volume weight blur. It's the most lightweight method and done all the time to have volumes as masks. Lots of volume tools to modify the weights as well.
Nice to have Houdini support volumes natively.
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@Jeff, I looked at your example and I think that one also works only as a simulation (so over time) whereas I want it to be unsimulated/instant. Thanks though, as I can learn from it.
Just to elaborate, here's another snapshot, from the delete by volume node in Soft - how it works inside. I think some of it corresponds to what Patar did. Am I right to assume that in H, you have to use volumes/VDBs to do this type of thing?:
Just to elaborate, here's another snapshot, from the delete by volume node in Soft - how it works inside. I think some of it corresponds to what Patar did. Am I right to assume that in H, you have to use volumes/VDBs to do this type of thing?:
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- druitre
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Hi Patar, when i translate the box in your scene, the effect disappears. Why is that, and how do i fix it? I'm trying to find out but no success so far…
- I can move the VDB, but not the input object - for a lot of purposes, it would be very useful if it could be the object that moves.
- I can move the VDB, but not the input object - for a lot of purposes, it would be very useful if it could be the object that moves.
Edited by druitre - Aug. 18, 2017 13:39:22
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I see what's happening - my scene is on a vastly bigger scale, I'm working with a couple of kilometers. If I scale up the box x 1000, the falloff range diminishes to near nothing. If I scale up the voxelsize x 1000, I keep the falloffrange but then when i move the box, it falls in between voxels so disappears. (If that is clear).
I'd have to increase the falloff range x 1000 as well to have it work, Band doesn't help either. I'll try some more.
I'd have to increase the falloff range x 1000 as well to have it work, Band doesn't help either. I'll try some more.
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