Visible Light beams in Vray Environment Fog

[haich11]

Hi Everyone,

I have been trying to set up visible light beams using Vray Environment fog over the last few days with limited success.

My main problem seems to be render/quality settings, as I can generate a pretty good preview of what I want to achieve (refraction, caustics, specular, etc). Please see attached screengrabs.

I cannot seem to find a happy medium between quality and render time, and was wondering if anyone might have a look at the scene and offer some advice? I have been tweaking settings all over the place, but I can't seem to refine the rendering of the actual light beam itself.

I would also like to be able to exclude GI and certain lights from affecting the fog, so as to speed up the rendering and control the look.

Link to scene: https://www.dropbox.com/s/tobufjziyg..._Forum.mb?dl=0

Any help would be greatly appreciated.

Thanks

[ivaylo.ivanov]

Well, what you are doing here is mostly light simulation, not rendering, so you will pay the price ... Read the help of the env fog, it's shown there how to choose custom lights and disabled the GI scattering.

[haich11]

Thanks for the response, ivaylo.ivanov.

I have no issue with render times being hefty due to the light sims, but I really need to be able to view the simulation in my viewport.

I have tinkered with the subdivs and the GI scatter bounces in EnvFog, but can't seem to get the light beams to display properly.

Any idea which settings I need to 'up' to see the light?!

[Svetlozar Draganov]

Would it be possible to attach the assets files used in the scene, without them the scene renders complete black.
Then would you please give us more details about what are you trying to achieve?

Environment Fog is not supported in the viewport for Maya native drivers but if you set the viewport the V-Ray RT it will be displayed properly.

[ivaylo.ivanov]

Here is what I can think of (I removed everyting non essential):

Light_Test_Forum.zip

First, I put the fog into a smaller box, so it renders faster and I can better control the opacity. Then I increased the fog color. In your scene, the diffuse is too low and the lighting is barerly visible. You try to cheat by increasing the caustics multiplier, but there is just not much light there. If you need low diffuse color, you may turn off the shadows to keep more lighting. The next difficulty is sampling this low lighting. It seems that using the image sampler to put the samples may be the better option, since it will probably find easier the light beam. However, you must increase the minimal samples, but 3 seems enough.

[haich11]

Thanks for the replies, guys.

I appreciate the time you've put in to helping with this.

I realise that this is a complete newbie question, but what's the method to assign geometry to the fog so that it acts as a container (like in ivaylo.ivanov's scene)

I found this on the manual: "VRayEnvironmentFog is an atmospheric effect that allows the simulation of participating media like fog, atmospheric dust and so. Volumetric properties can be determined by 3d texture maps. The atmospheric effect can also be confined with geometry objects. " but I can't see how to actually assign the geometry to fog.

Any pointers?

Thanks

[t.petrov]

The EnvironmentFog is a set, so if you add geometry objects in it, it will used them as gizmos - it will fill them with fog.
Don't forget to make the objects transparent, so you can see the fog inside.

[haich11]

Thankyou, t.petrov.

[haich11]

So, I'm making some good progress on this scene. The lights are visible and volumetric, and the refraction/reflections are creating some interesting visuals.

My biggest problem is render times now. I think because I've gone so far 'down the rabbit hole' tweaking settings, my render times are massive.

I'm no longer sure which light subdivs/environment fog settings/render settings are causing it to slow so much.

I appreciate that they're likely to be quite big due to all the light interaction, but I can't seem to bring them down and still render at reasonable quality.

Might someone out there who knows what they're doing have a quick look at my scene settings and advise accordingly?

This is currently SD, and the final output might need to be bigger than HD. This is starting to panic me!

Here's a link to the Archived project: https://www.dropbox.com/s/hd8wisrwa5...02.mb.zip?dl=0

Many Thanks

[Svetlozar Draganov]

The higher render times in this scene are caused not only by the environment fog but from reflections/refraction/GI/caustics/IS and etc.
The strange thing is that it renders almost black into our environment although only Rock_01.bmp texture is missing:
https://ftp.chaosgroup.com/support/s...t-18-26-54.png

Can you show us how the render output looks like in your environment and for how much time was being calculated?
If possible please attach the missing texture so we could see the render output into our environment.