vRaySun turning Volume Fog (for clouds) into black clouds?

[om1nous]

Hi all,

I'm pretty new, FYI! (post count? hehe)

I have a scene which I'm just flying a plane through clouds generated by Volume Fog. They're white and just how I liked them while I was using no lights (default lights) and continue to be white if I add a Vray Light (plane,omni,anything). However if I try to add a vRaySun to the scen all of my clouds have turned black.

Can anyone tell me what might be the cause of this? Does Vray work nicely with the built in 3ds max Volume Fog?

Thanks for any tips!

[vlado]

I don't think it'll work with the VRaySun, you'll have to use a normal direct light.

Best regards,
Vlado

[om1nous]

Oy vey, no real specific reason aye..

I'm very new to VRay.. I'll try the direct light method but I have a huge scene where a plane is flying in a straight line. It's also contained inside a huge sphere (because volume fog needs to exist 'inside' something). If I turn on that a light never falls off, the whole inside of the sphere just turns white. Is it really going to be possible to make a light that works like sunlight inside a sphere? For some reason, sunlight didn't blow everything out.. Any tips on settings?

Thanks very much!

[Da_elf]

you might need to A: tell the sphere not to case shadows (in object properties) and B: not to affect GI (in vray properties)

[om1nous]

Hiya!

NOTE: Some large screenshots below, I GIF'd them as small as possible, sorry! Pictures worth a million words..

I already have cast shadows off but I can't seem to find the affect GI setting. I never noticed if objects themselves have any vray settings but I don't see any (you specifically said it's a vray settings and I'm a newbie). The mental ray tab has a setting for "Generate Global Illumination" but I'm not using that renderer. Does that setting still somehow carry over to Vray?

I ended up cutting the bottom of the sphere off to make a dome (hoping light would escape and not hop around) and extended the bottom. It didn't help unfortunately.

I'll just post a screenshot of the simple scene and the setting you refer to might just be here and I glazed over it.

Here's the basic scene setup (full compressed screenshot, dome object properties and vray light plane config):


Vray settings (for quick renders during testing):


Environment panel:


Should I be using another type of light? I thought a plane would let me angle the light similar to a sun and by setting no decay, I thought it would evenly light everything in that general direction. Upon render, this scene has no light at all so I didn't bother including a screenshot of pure black .

Thanks for any settings tips!!

edit:

BTW on the dome, I checked "Exclude from advanced lighting calculations" on the Adv Lighting tab in the object properties, if that matters..

Re-edit:

Should have known one thing from photography.. I'm using still camera mode on the camera and I'm not managing the settings. I adjusted aperture and film speed and now I can see the plane, but still, my light has absolutely no control in this scene. I somehow can see lighting EVEN when I have no lights in the entire scene enabled (????). I have Default Lights disabled as you can see in settings but I'm getting an overall lightness (ambient light is also set to black (off)).

I do have a background image I want to use slugged in there of clouds, to go along with the clouds I'm generating. That's affecting the color of the plane. I disabled the Vray GI override and I set the environment panels global lighting to 0.0. Unfortunately it has no effect on the scene at all. Disabling Vrays GI (1.0) did shift the color of the scene though, so that was affecting it somewhat.

Still at square 1. I now have a Vray plane, dome and sphere hovering directly over the plane and I crank up the power of the light (no decay, or decay both) to even say 50,000, and it doesn't touch the plane at all. Any ideas on why that is? I toggled the lights power mode from image, luminous power, luminance, radiant power and radiance and none of them have any effect on the plane (outside adjusting the multiplier to random huge numbers).

[jacksc02]

why dont you try using VRays environment fog?

[om1nous]

Hmm, I just found a tutorial on how to do just that and I'm going to play around with it. I did realize that after I set up everything like the default settings in the tutorial, my render time went from 2 seconds per frame using Volume Fog to um....... 15 minutes per frame using VRayEnvironmentFog????? Happen to know what setting of VEF would cause it to choke up that much? Mind you I'm rendering on a dual-quad (24ghz) xeon with 32gb ram. I don't think it's really useful if that's how much calculation it requires and I need to animate.. If it were stills, that'd be a different story

Besides, is there really no way to do this with just what I have? I long ago converted the whole scene to vray and everything is a vray material. The plane was made by Giimann so it was already Vray. I'm using a Vray physical camera. I'm using a Vray light (sphere for example) at a huge intensity multiplier directly above the plane only 2-3 feet away. I can't see any light at all in the plane from it. Isn't that strange?

[vlado]

What would be the problem with using a direct light?

Best regards,
Vlado