Question About Volume Light

[InfernalDarkness]

With Maya's renderer, just use Light Fog.

With mental ray, you'll have to use the parti_volume shader and the accompanying workflow. It's a pain in the ass, but keep at it and you'll eventually figure it out.

[gokalpgonen]

i tried with light fog but i couldnt get the shadows in fog. How can i get them?

[InfernalDarkness]

You'll have to use RayTrace shadows. I'm not sure if they'll pick up the color or not in Maya Software, but I'll test it later tonight when I get some time.

If you're casting light through glass, and going for realism, you'll want to use mental ray instead. A bit more work, but it will look much better in the long run.

[Libor]

1) create box surrounding your objects (ie scene)
2) create spotlight lighting main actor (your subject)
3) assign transmat to the box from step 1 (use rightmouse> "assign new shader" and choose the transmat)

4)go to SGshape group of the box and assign "parti_volume" custom mray shader into "Volume" shader slot (in mentalray area not the standard maya one!) (beware there is also parti_volume_photon for advanced gi computations) so you end up with transmat in standard slot and parti_volume together in SG group

5) render with mray (tune the parti_volume shader properties, namely color > put a bright color there for colored fog)

Thats it and its not a pain in the ass at all!

L.

[gokalpgonen]

thanks i will try :bounce:

[InfernalDarkness]

Interesting workflow, Libor! A few differences in my experience (but please try it his way first, gokalpgonen)

3) assign transmat to the box from step 1 (use rightmouse> "assign new shader" and choose the transmat)

This step isn't necessary, as you'll need to set "suppress all Maya shaders" in the Shading Group anyway.

Also, on your light itself, you'll need to go to the mental ray section in the shape node and set the light to the MR shader, "Physical Light". You'll also need to make sure in your parti_volume that your light "spotLight1" is in the light slot, or whichever light you're using.

The main difficulty I've had is adjusting the scatter and color to make the volume visible. Numbers over 1.0 are generally necessary, sometimes as high as 10,000. Perhaps this is the main difference in Libor's workflow; I'm gonna try it his way and see if it's easier.

[nfrancisj]

you can check this out when you get a chance... I made it for another guy on CGtalk who had a similar question...

http://rapidshare.com/files/252129207/volume.avi

[gokalpgonen]

this is wonderfull. Thank you. Helps a lot :bounce: :bounce: :bounce:

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