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View Full Version : RT shadows kill my volumetric light



Johnny
08-24-2006, 04:11 PM
I have a volumetric light doing just what I want it to, but when I turn on RayTrace shadows in the Render options (I'm using a Distant light for Sun)
the volume produced by the volumetric light loses it's diffuse quality..should look like fog and smoke and instead looks like transparent color on a transparent sheet of plastic. all body is gone.

I am not getting why RT shadows would cause this, but when I un-check them, the volumetric light behaves as it should.

Any thoughts?

thank you greatly!

J

Bytehawk
08-24-2006, 04:39 PM
do you have rt shadows on in the render globals panel as well ?

Johnny
08-24-2006, 04:43 PM
either I'm not seeing it or I don't know which panel you're referring to...

in Render Options, there's a box for Ray Trace Shadows, and in the Global Illumination panel, the only shadow-related checkbox is for Shadow Maps..

Is there another panel in there somewhere that I missed?

thanks!

J

JamesCurtis
08-25-2006, 06:20 AM
If you are using LW9, you will find the Raytrace Shadows button by going to:

Render Tab > Render Glodals [on menu sidestrip] > Ratrace Shadows [button 2/3 of the way down the panel].

If you are using LW8, you will find the Raytrace Shadows button by going to:

Render Tab > Render Options.

Johnny
08-25-2006, 08:43 AM
If you are using LW8, you will find the Raytrace Shadows button by going to:

Render Tab > Render Options.


Right.

That box, I have checked, and when it is checked is when my Volumetric light "fog" gets wrecked. Un-checking that box you describe above restores the quality of the volumetric light.

So, seems I can't have the good volumetric effect, AND RT shadows.

J

Bytehawk
08-25-2006, 09:34 AM
and if you set the light to shadowmaps, does it render correctly then ?

I can't recall if this is is a limitation or if that limitation has been eliminated in the course of hv upgrades from 5.6.

Johnny
08-28-2006, 10:18 PM
and if you set the light to shadowmaps, does it render correctly then ?

I can't recall if this is is a limitation or if that limitation has been eliminated in the course of hv upgrades from 5.6.


this scene uses a Distant light as the shadow-casting light, and only RT shadows are available for it.


J

Sekhar
08-28-2006, 11:09 PM
Is it possible the volumetric portion is falling in the light's own shadow? I mean, since the light is distant, volumetrics start from the physical location of the light, but the light itself would come from infinity...

jameswillmott
08-29-2006, 01:12 AM
Is Opacity Casts Shadows option turned on for your volumetric light? If it is, try turning it off and see if that helps.

Johnny
08-29-2006, 08:38 PM
Is Opacity Casts Shadows option turned on for your volumetric light? If it is, try turning it off and see if that helps.


that was off already, but thanks for the idea


J

Johnny
08-29-2006, 08:39 PM
Is it possible the volumetric portion is falling in the light's own shadow? I mean, since the light is distant, volumetrics start from the physical location of the light, but the light itself would come from infinity...


this partic light points straight up from ground and has all other objects off and doesn't cast a shadow itself.

J