Vray Scatter Fog

[Reaversword]

I've been playing with Vray Scatter Fog node, placing it in material volume slot of the material, with a transparent vraymtl material in the material surface slot.

The only way I found to get results is setting the bias between 0 to 1, but only got equivalent results that "vray environment fog" node offers. Basically while with Vray Environment Fog doesn't offer us and Ior, and and scatter coefficient (for choose how many dispersion we want) and scatter direction (for get our light beam forward or backwards), Vray Scatter Fog does, but I can't get it working

So, is correct use Vray Scatter Fog in material volume slot?. Or we should use it in other place to access this extra controls?.


If we want render a light beam in a volume -supossed- water. Would be correct use a Vray Environment Fog in material volume slot and stablish a vrayMtl in surface material, with no diffuse, no reflect, all refract with the ior of water?. Although if we don't use Vray Scatter Fog, at least we could control the Ior of the participating media?

Is actually Vray Scatter Fog in development?.

[vlado]

The VRayScatterFog is the same shader that is used internally for the translucency in the VRayMtl material. You can use it either in a material volume slot, or as a global environment shader. You might want to turn on the "Environment fog" option, otherwise the fog will not receive illumination from lights. I'd still recommend using the environment fog though, which also offers some scatter direction control through the phase function parameter.

Best regards,
Vlado

[Reaversword]

Ok, I'm gonna take a look again. I must test the phase function attribute (in first I believe this was only for textured volume environment fog).

I recognize I didn't check "Environment fog" and don't play with it, but was because in documentation says that check it is for use it in the whole scene and I'm using it in a specific volume.

Nevermind. Thank you for the point, Vlado!.


Edit: Yes. It works perfectly. Perhaps would be ok update the description of the parameter in the documentation or clarify a little bit more. (I hope it doesn't be my fault for bad-english-misunderstanding-problem!).

...err.. where's phase function attribute of environment fog, you mean "scatter GI", don't you?

[Svetlozar Draganov]

...err.. where's phase function attribute of environment fog, you mean "scatter GI", don't you?

There is no phase function in VrayEnvironmentFog - so if you want to use such functionality it should be better to use VrayScatterFog>Scatter Direction parameter.

[Reaversword]

Yep Svetlozar. There is any parameter like phase function on VrayEnvironmentFog, but I interpreted Vlado was talking to me about VrayEnvironmentFog node, in place of "EnvironmentFog" attribute of VrayScatterFog. That's my confusion.

Anyway. Using VrayScatterFog perfectly now, thanks to both for put me in the right way!.

[vlado]

Sorry about that, I was thinking about something that I'm working on - it's not in the builds yet.

Best regards,
Vlado

[Reaversword]

Don't worry about Vlado. Enought things you have in your mind how for be remembering which ones is in the builds and which ones not. Your intention always has been help and support us, so, nothing to apologize.

Thank you both one more time.

[ignuf]

Hi Reaversword,
i've just been reading this post re vary scatter fog, and was wondering if you could possibly help , Ive got a scene which starts with a camera "under water" looking up at the water's surface, up until now I've been using env fog plugged in to the environment shader in the render settings / vray tab, which has been ok up to a point , Vlado has suggested maybe using the scatter fog , but so far i've not managed to get anything good at all , would it be possible if you could advise me on initial setup ?

ive checked the " environment fog " option in the scatter fog node , but so far the only way i can thin out the fog is if I set the colour to absolute white, anything less than white makes the fog extremely dense and everything is extremely dark...

thanks for any help !!

regards
ignuf

[Reaversword]

Hi Ignuf!.

There was a time of this, but, I'm gonna point you to this thread:

http://forums.chaosgroup.com/showthr...light=caustics

Yes, I hate when somebody in a thread answers pointing to another thread, but this is the good one, and here is where I realized about one of the most important things is the position of the camera (inside of the caustics volume, or not). Besides, you'll find some scenes with some examples to play with.

Let me know if this solves your problems!.

Edit: And take a look at this one too for get rid of this spotty renders

http://forums.chaosgroup.com/showthr...light=caustics

[ignuf]

thanks so much Reaversword,

any pointers in the right direction are always appreciated ! i'll take a look and see

thanks again and regards
ignuf