Shadow map vs Ray Shadow

[boby]

Hi all,

I try to create GodRay with Vray Blender. In3DSmax, GodRay can be create with the "volume light" atmosphere effect and light using shadow map.
My probleme is that i don't find any checkbox to switch between shadow mapp and ray shadow. And I don't find the "light volume" effect...

Is this not implemented yet or am i missing smth?
Do you know another way to simulate godRay with Vray/Blender at render time (i already know the composite tricks)

Thank's

boby

Edit : I believe it can be simulate with a fog effect, but still need shadow map to work

Edit2 : Ok my bad, it works well with ray shadow and fog effect. It's slow as hell but it's ok

[MattVG]

Re: Shadow map vs Ray Shadow

Would you mind sharing how you set it up? I'm new to VRay Blender and attempting to create light rays, but all I ever get is a black scene without light.

[boby]

Re: Shadow map vs Ray Shadow

Hi Matt,

In fact, it's a bit tricky, and i'm not sur it's really optimized.
Just but a cube and set it in the world panel as a fog effect container.
You ll have to make several try to find good setting according to your scene (lighting and scale).

For this scene : http://vray.cgdo.ru/forum/viewtopic....f461c5350e46ae (that's not really god rays, but i think you can use the same technique),
i used a sun lamp with physical cam and a high fog density to simulate this effect.

boby

[MattVG]

Re: Shadow map vs Ray Shadow

Boby,
Ooh! I really like that image!
I actually managed to get slight light rays showing up (and not complete darkness) by enabling FOV under the Physical camera options. I'll try it with a fog effect container. Though, I thought light/god rays didn't work with sun lamps due to the way shadows are calculated. I must test some more. Thank you for your input.

Matt VG