Opacity maps and VRayEnvironment fog

[F801]

Does anyone have any tips for rendering opacity maps with VRayEnvironment fog? Cards are showing once fog is turned on (see below). My opacity maps are pure black and white. It looks particularly bad in the section below where a spotlight hits (I'm having to use a Maya spotlight rather than a Vray light as I'm using gobos and the VRayRect light was too harsh)

I've found several previous posts on this topic but can't get a solution.

Any help appreciated.

[damaggio]

You didn’t show the maps and the connections , this is very simple , think of a set up with a tree with opacity leaves, should be the same in most cases, I usually use a png with transparency, it works great,

[FauntailJabuti]

Yeah I’d love to the map of connections.

[F801]

All maps are jpgs.

[damaggio]

Transparency map, check alpha is luminance or convert diffuse map to png transparency so you don’t need to upload another file just for transparency therefore making scene lighter,
connect diffuse out alpha to opacity.
you can also delete roughness and use a HSV node from the albedo to roughness slot.
the fewer maps to deal with the better.
in other words , these are just twigs and it could be simplified, you’ll never notice any difference .

[F801]

Thanks for the suggestions. I've tried disconnecting all maps but the diffuse png (with transparency). Opacity works as expected until fog is enabled. As soon as fog is enabled the cards are visible.

[damaggio]

Here is my test, it works fine, without your scene file there's no way to check the other settings.

[FauntailJabuti]

Hi guys, I hope @F801 Doesn't mind but I also have a question regarding opacity maps and fog so I thought I'd save the forum an extra posts, and place my question here. Certainly don't mean to step on anyones toes, and if this topic should be migrated to a page of its own, just let me know!

I'm trying to recreate the demo found in the documentation. I'm linking and supplying an image below to help clarify.

https://docs.chaosgroup.com/display/...EnvironmentFog


I've tried applying a checker texture to the environment fog node, but that doesn't seem to do anything and I don't understand why. Also, I've still not addressed how to confine fog to a specific geometry. Ultimately, I'd like to be able to know how to assign fog to GEO. I'm attaching the map below of one of my attempts. Any help is deeply appreciated.

[damaggio]

this well done video by Carlos Alvarez covers everything about Vray fog attributes and common mistakes. https://m.youtube.com/watch?v=TqwPNHIIXgo&t=1416s

[FauntailJabuti]

Thanks dimaggio. I just got done watching it. Going to try to mock things up and follow along.

[FauntailJabuti]

Thanks for posting this Video dimaggio. One thing I still don't understand is that in the documentation they mention that they used a checker texture applied in the density channel of the enviro fog. But all of the examples I see of carlos's are utlizing 3D textures, not 2D textures. I'm wondering how the chaos group dudes did that checkered smoke.

[Zdravko.Keremidchiev]

I'm wondering how the chaos group dudes did that checkered smoke

If you set the Checker as projections and enable its Alpha is luminance you will get that effect.

Opacity works as expected until fog is enabled. As soon as fog is enabled the cards are visible.

F801 Can you attach a simple example scene?

[FauntailJabuti]

Hi Zdravko.Keremidchiev, I can't thank you enough for taking a look at this. I spent the whole day yesterday trying to get to the bottom of it. I'm attaching the file.

I think I might be doing it right for the most part, but where do I "Set as projection?"
thank you!

[FauntailJabuti]

Hi Zdravko.Keremidchiev, after two days I figured it out. I suppose I forgot about "Set as projection." Also, I didn't know that the checker texture would not work with PRODUCTION ENGINE set to RTX. Is it safe to infer that trying all things set to CPU first and then trying to see if CUDA or RTX engines would render the same result? or is there some sort of centralized page/ chart that indicates which features do or don't work with certain engines? thanks!

[F801]

Here is my test, it works fine, without your scene file there's no way to check the other settings.

damaggio thanks for all of the suggestions and the effort in building a test scene. Mush appreciated. I still can't get opacity to work in my scene.

@Zdravko.Keremidchiev - I'll build a simple scene tonight and attached.

Thanks.