Volumetric Lighting

[p@g0]

humm.. you want to try this little trick :)

create a similar object... actually.. the shape you want the shadow or the light to be... now assing a shader with a glow on it.. but you have to check the checkmark HIDE SOURCE...
so you wont see any object.. only a sort or glow.. or a shadow!

pretty cool effect when you want to fake light commin from a window!

[alexx]

that is a typical effect you should do in post.. u use the alpha channel of the object to drive a radial blur..

cheers

alexx

[ASW]

But I need actual volumetric shadow, as the redial blur alpha method doesnt realy capture the Zdepth and multiple object interaction I'm looking for. in XSi all you do is add volumic properties to light and then click the add volumic shadows, and voila Volumic lights with shadows. I've added volume fog to my spot light in maya and tried some fractal shaders but I cant seem to get what I'm looking for. heres my hyper graph with example
any help you can give me would be sweet


ASW

[TheWraith]

have to use depthmap shadows. raytrace shadows won't produce the volumetric shadow effect or rays for shadows. or maybe i'm wrong and it's the opposite! maybe it's only raytraced shadows that produce the effect. can't remember but i know it's either raytraced OR depth map and not both. i'd do a quick test to find the answer out for u but i'm lazy :P

[nemirc]

Maybe it's a dumb question, but I have to ask: What is a volume shadow? :rolleyes:

[Anteru]

It definitely works with DMap shadows. You just have to make sure the volume is big enough, i.e. the new cone which is added to your lightsource shows where the volume is, scale it! I didn't manage to get it work with ray-traced shadows.

[ASW]

Now I've got to see if I can get some rays in the light, otherwise it looks a little stagnent. Heres a picture of of what volumic shadows are for our boy who not in the know. I haven't added any volume properties to this beem, straight up light fog with depth map shadows (no raytrace). Now if anyone know how to get a good over all fog atmoshere to room, I really want to create a low laying fog on the ground for my creature to walk through. Anybody whos got any idea on how to achieve this, any help you can give me would be sweet. And thanks to everybody who helped with my question BIGUPYOURSELF

ASW

[TheWraith]

you could get completely realistic and interactive fog on the ground by using maya fluidFX... but you would need maya unlimited 4.5/5 and either a TON of time or a renderfarm if you want it animated. whats wrong with using maya's environment fog? otherwise i guess i'd go with a spotlight from above that had either it's intensity or color mapped with a ramp so that the fog would only show up near the ground. use a 3d map like fractal or cloud for the fog texture

[nemirc]

Oh! I see.
I thought that was the one but I wanted to make sure :blush:
I can believe I've made that effect before and I didn't even know the "technical name" :cry: :drool:

[ASW]

How would I go about doing that, would I use a cube and fill it with enviroment fog, making the cube surface non rendering?
This is my best guess Any advice you can give me would sweet ass. thanks.

asw

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