OTOY Forums

Hello all,

I can't find the volume emission node ? somebody can help me please ?

Matt

Hi,

You can use the same types of emission node as you would use for a regular emitter.

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Roeland

Hi,

Ok I found, I'm not understood that it was on the scattering node with specular material. I tried with and without emissive and I found without emitter, I had better result without emitter.

Here some 30 min test, using the same setup I used in renderman for volume ( frustrum box that never cut orign of camera ) :





In all ways, it's a good trick, but it'll be better with a real raymarcher to had shadows in the volume. But for my current project it's just what I need.

Thank you for help

Matthieu

wow!...
realistic fog
why objects don't occlude the fog?

Hi gabrielefx,

This fog was made by using in a "wrong way" a subsurface scattering function, so algorythm for SSS and raymarching have some differences, the rays not take the same path. I think this is why, I can't obtain the shadows in the volume, or maybe it's the scale of the scene. I'll try other idea to see if I can have better result, but I had the shadows from the cone, whose hide a part of my emitter so maybe is just a problem of setup.

Matt

wow! that looks pretty amazing
i must admit, i don't understand how you have done that. would you mind posting the setup or maybe even the scene?!?

Hi all,

So, in attachment, a scene file, whose contain the setup I used. The most important is the scale of the scene, intensity of emitters and the scale of the scattering node, that determine the density of fog. To much density, the scene turn to black, cause to much absorbtion by the volume. You need to change scale of scattering by scene. if you unplugged the mix node, from scattering you will have a uniform fog. Be carefull, to bounding box your volume fog to never cut it with the camera plane, the camera need to be always out of the box. One setup is to use, a box that match your frustrum camera, more easier setup.

I put also a screenshot from my maya setup, and result from the octane scene.

Enjoy !!!

Scene File :
http://www.megaupload.com/?d=1UJ4C5E2

Matthieu

http://mattrm.blogs.3dvf.com/

Thanks for sharing... must try this. The megaupload says the scene is unavailable.
At your convenience would you mind re-posting it

Thanks

Peter

Humm, yes, this is strange, but new link here :

http://hotfile.com/dl/138855201/cf3de5b/TEST_FOG.rar.html

Matthieu

That did it. Many thanks

Enjoyed your blog
Will let you know if I create anything with the fog technique