Pyro Shader Displacement

Forums Houdini Indie and Apprentice Pyro Shader Displacement

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pelos: Member; 621 posts; Joined: Aug. 2008; Offline

June 7, 2012 5:49 p.m.

Has any one had time to play with the pyro shader displacement,
i wonder how does it work, does it create noise on the volume, or does displace the voxel to create wispy fealing in the edges,
since the field say N i am assuming Normals.

any ideas?


Alejandro Echeverry: Member; 691 posts; Joined: June 2006; Offline

June 8, 2012 12:01 p.m.

Mantra dice the voxels in to microvoxels (like other surfaces), then displace along a given vector; In this case you can define a vector from a 3d noise directly in the pyro 2.0 shader or calculate the gradient of the density to use that as a vector field (normal).

Here is an example file, unfortunately if you use any of the raytrace engines, the render gives nans and very odd artifacts.

Attachments:
Pyrofx2.0_displacement_test.hip (917.6 KB)

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pelos: Member; 621 posts; Joined: Aug. 2008; Offline

June 8, 2012 6:45 p.m.

that's awesome, so the displacement is doing the noise?

how can i apply it to a pyro sim, i did a sphere and put a flames with smoke preset.
the smoke is not a SDF its just density right?


Alejandro Echeverry: Member; 691 posts; Joined: June 2006; Offline

June 8, 2012 6:58 p.m.

You can calculate the gradient from a fog also, if there is enough density change in the field (high dissipation fields) to determine the gradient, if not, convert to a sdf in sops with a volumesdf node then calculate the gradient.

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Nic Yiallouris: Member; 4 posts; Joined: Sept. 2013; Offline

June 11, 2014 3:51 p.m.

I'm struggling to get my head around this in H13.

Would you do this with an “iso offset” or with the “vdb analysis” ?


Alejandro Echeverry: Member; 691 posts; Joined: June 2006; Offline

June 11, 2014 4:54 p.m.

Now you can use all the nice vdb tools to do this!! Its waaayyy faster!!

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Nic Yiallouris: Member; 4 posts; Joined: Sept. 2013; Offline

June 11, 2014 6:07 p.m.

Perhaps you could shed some light on my workflow, I've attached a file where I've started to calculate the gradient but I'm not sure of my methodology.

Attachments:
PyroDisplacement_v01.hip (1.6 MB)


Alejandro Echeverry: Member; 691 posts; Joined: June 2006; Offline

June 11, 2014 6:37 p.m.

Here is the correction. Hope that helps!

Attachments:
pyrodisplacement_v01_148.hip (1.6 MB)

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Nic Yiallouris: Member; 4 posts; Joined: Sept. 2013; Offline

June 11, 2014 6:51 p.m.

You are a master !

Thanks

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