God Rays in Vray?

[Crazy Homeless Guy]

....is there an easy way to render god rays in Vray? Or, does anyone have a suggestion for this?

 

i am looking for the equivalent of the link below. I suppose I could flip the scene to MR render out a pass for comp, then flip back, but is there a way to do it natively?

 

http://forums.cgarchitect.com/38024-god-rays.html

[kippu]

will the vray fog not work for this?

[ctk111]

Yeah i think vray fog is the way to go. here's a tut from evermotion

 

http://www.evermotion.org/tutorials/show/7817/3dsmax-vray-volume-effect

 

here's another with a similar effect but comped in photoshop after using basic max volume lighting

 

http://www.evermotion.org/tutorials/show/7814/3dsmax-vray-lightmap

[Crazy Homeless Guy]

Perfect. Thanks.

[Eric Sosa]

haven't read all the threads about this godlight thing but....

 

easy; volume ligth through a grilled surface.

 

made a little tutorial about using volume ligth here

http://www.vray-materials.de/forum/showthread.php?tid=444

 

the volume ligth "edge" can be sharper & smooth using the grilled surface somewhere between the direct ligth & the "window".

[mfured20]

Check out Peter Guthrie's images made with vRay Enviro Fog... He gives a quick breakdown of his Fog settings. I have been playing with this, and love it thus far.

 

Check out the rest of his blogs, he has some amazing tutorials and examples up there.

[BVI]

Off topic, but have you seen the God Rays in Vue - wooow!

http://ih3.redbubble.net/work.4364809.1.flat,550x550,075,f.jpg

[Eric Sosa]

this quick renders were done using volume ligth...as explained before.

[Camby1298]

I messed around with VrayFog for a few hours.

 

When I enabled "Scatter GI", the lighting in my scene became very merky and muddy. I tried cranking the GI Bounces, but no matter how High I went I couldnt get it to my liking (plus the render times were increasing in length). If I was to render a scene within a swamp, this would work. But for general Arch Viz Scene I was looking for something cleaner. Maybe Im overlooking something??

 

By disabling "Scatter GI", it confines the fog within the light volume, and does not affect any other surrounding. I can then take this image, place it on top of my beauty pass and give it a screen blending mode in Photoshop. From there I can control the intensity by adjusting the opacity or by dublicating the layer.

[Chad Warner]

Sorry to hijack the thread slightly, but I've just started to try using this, and I'm having a heck of a time getting it right. What I'd like to be able to do is have the volumetric lighting show up, but only in the cone of the light that it is applied to. It appears that in order for the effect to work, you have to have a fog depth set, which basically recreates Brian's middle image above, but what I'd like to have happen is just a spot light with volumetrics. I've got an animation that needs "sky trackers" shown dancing around the exterior or the building and I'd like to have a "foggy" effect just for the lights and not the rest of the scene.

 

Can anyone help?

[Camby1298]

Sorry to hijack the thread slightly, but I've just started to try using this, and I'm having a heck of a time getting it right. What I'd like to be able to do is have the volumetric lighting show up, but only in the cone of the light that it is applied to. It appears that in order for the effect to work, you have to have a fog depth set, which basically recreates Brian's middle image above, but what I'd like to have happen is just a spot light with volumetrics. I've got an animation that needs "sky trackers" shown dancing around the exterior or the building and I'd like to have a "foggy" effect just for the lights and not the rest of the scene.

 

Can anyone help?

 

If Im understanding correctly, With Vray Fog, you can chose which Light is affected (doesnt have to be the sun). Select your light, render the prepass and overlay the images on top of your animation.

[Chad Warner]

The issue I am having is that I can't get the spotlights to have fog without there also being fog in the scene as a whole.

[Camby1298]

Can you post your settings and your scene? Im pretty sure I know the solution but I just want to make sure I know where your coming from.

[Chad Warner]

Sure can. With this scene, I actually started with the example file on the spot3d website for environment fog and caustics, and tweaked it to match what I was trying to do. (its a max 2010 file).

 

thanks!

[DanGrover]

Sure can. With this scene, I actually started with the example file on the spot3d website for environment fog and caustics, and tweaked it to match what I was trying to do. (its a max 2010 file).

 

thanks!

 

I've always found that there are three ways to add fog to volume lights.

 

Firstly, to add noise. This looks a bit crappy though, as there's no physical reality to it. So it'll just randomly fizzle about irrespective of any scene conditions - for example, in "real life", it'll always mostly all flow in one direction because there's always a breeze, no matter how subtle.

 

The second is only for absolutely mad people, and that's to use particles to create the volume. As I say, you have to mental to do this, but it can look lovely.

 

The third is the way I do it - comp it in afterwards. Get a video of some smoke on a black background (a la the wonderful Detonation Films free stuff area) and use the volume light you rendered as a mask for this. I tend to combine both this layer (the smoke with the mask) along with just the volumetrics themselves at varying opacities depending on the scene in question. You can get some really great looking results. This is a still from a render I've been doing recently. I can't post the animation, but you can see the fogginess in it, and it moves quite nicely.

[Chad Warner]

Dan-

That looks really great, but I am having issues with just getting the volumetric light looking correct.

[Camby1298]

Only thing I can think of at this moment is if your wanting to have the fog effect within a light, but not influence certain objetcs; than inside the "exclude" list of said light, exclude those objects that you dont want influenced by the light. Or Hide them from the camera, do a Volume Effect Pass and overlay in your animation.

[DanGrover]

Dan-

That looks really great, but I am having issues with just getting the volumetric light looking correct.

I found really big issues if I used a vray physical camera. I had to lower the exposure time to about 0.01 for them to show up properly.

[Chad Warner]

I don't think I'm doing a very good job of explaining what I want to do, so here's an example of the effect I'm trying to recreate. So far the only way that I can get fog in the light is to have fog all over the scene, but I only want fog to show up in the lights, and not anywhere else. If I was using scanline, it's as simple as adding a volume light effect to the spotlight and hitting render. I just can't seem to get the same effect with vray.

[DanGrover]

It should be an identical process in VRay - what's coming out at the moment? No fog (aka volume) at all?

[Chad Warner]

This is what I get out of VRay, using a vray camera, sun and GI. The cut off mark on the light source and the gradient happening in the background is a result of the "height" of the environment fog being set to lower than the light source. In order to get the full cone of light to show up, the height has to be set higher, which then makes the entire scene (other than the light and the sphere) dark.

Edited April 6, 2010 by Chad Warner

[Chad Warner]

Alright, I've decided that since it's so much easier to do the volume lights in scanline, I'm rendering them in scanline and comping them in after effects. I'm still interested in how to do it in Vray though.