topic Re: Transmission has a glowing rim when layering two objects with transmission in Arnold for Maya Forum

Transmission has a glowing rim when layering two objects with transmission

chris.bruinXRJUW — Tue, 10 Dec 2019 14:48:35 GMT

I am experiencing an issue with my eye setup. As you can see in the image below, I have a glowing rim around the edge of the eyeball in the transmission pass. The caruncle geometry overlaps the eye, and both have transmission enabled.

Both the caruncle and sclera materials are using the aiStandardSurface. Both have Opaque set to Off, and both are using Transmission. The head, caruncle, and eyes all are part of the same SSS Set Name as well.

Here is the shader setup for both caruncle and eye:

As you can see, both are very similar, the only difference being that the caruncle has a bit of control over the transmission depth. Disabling this and matching the eye still gets the same results.

Any ideas how I can remove this weird rim light on the transmission pass? It appears only when the eye is in shadow, as the other eye, in light, doesn't have the rim visible, as seen here:

Lastly, my render has little red dots all throughout, they don't appear in any AOV, only in the beauty pass. Clamping values doesn't remove them. Any ideas there?

I am running the latest Arnold release, 3.3.0.2 - f5753062, in Maya 2018.

Thanks.

Re: Transmission has a glowing rim when layering two objects with transmission

lee_griggs — Mon, 16 Dec 2019 13:14:36 GMT

Are you using SSS Set Name?

Which SSS type are you using?

Re: Transmission has a glowing rim when layering two objects with transmission

chris.bruinXRJUW — Wed, 08 Jan 2020 07:57:13 GMT

I am using SSS Set Names, all objects are set to "1".

I am also using randomwalk_v2 for all objects.

Re: Transmission has a glowing rim when layering two objects with transmission

lee_griggs — Wed, 08 Jan 2020 08:26:09 GMT

Do you have a simple scene that reproduces the issue with red pixels?

Re: Transmission has a glowing rim when layering two objects with transmission

chris.bruinXRJUW — Wed, 08 Jan 2020 09:21:35 GMT

I tried rendering a simple scene, with just the head and a single area light. The red dots in the original post weren't the only color, so in this render some of them are now blue.

Re: Transmission has a glowing rim when layering two objects with transmission

lee_griggs — Wed, 08 Jan 2020 09:42:51 GMT

The light intensity is very bright. Does lowering the intensity affect the pixels?

I would leave Intensity at 1 and just use Exposure.

Re: Transmission has a glowing rim when layering two objects with transmission

chris.bruinXRJUW — Wed, 08 Jan 2020 10:07:13 GMT

I did that with the HDRI dome I was using, it was a default value of 1, and then I just adjusted the exposure values, which was used for the original render that shows the red dots.

Re: Transmission has a glowing rim when layering two objects with transmission

lee_griggs — Wed, 08 Jan 2020 10:49:17 GMT

ok, do you have a simple scene that we can test?

Re: Transmission has a glowing rim when layering two objects with transmission

chris.bruinXRJUW — Wed, 08 Jan 2020 11:32:30 GMT

I can assemble one for you, is there an email I can send it to? This project is confidential as it's owned by my company, so I can't post a public link.

Re: Transmission has a glowing rim when layering two objects with transmission

lee_griggs — Wed, 08 Jan 2020 11:35:25 GMT

Can you just assign the shader to a sphere?

Re: Transmission has a glowing rim when layering two objects with transmission

chris.bruinXRJUW — Wed, 08 Jan 2020 11:39:58 GMT

I can do that, but I also can't post the textures publicly. Without the textures, the sphere renders without those dots.

Re: Transmission has a glowing rim when layering two objects with transmission

lee_griggs — Wed, 08 Jan 2020 11:41:58 GMT

ok, email me - lee at solidangle dot com

Re: Transmission has a glowing rim when layering two objects with transmission

lee_griggs — Wed, 08 Jan 2020 15:38:39 GMT

Where should I see the odd pixels?

Re: Transmission has a glowing rim when layering two objects with transmission

lee_griggs — Wed, 08 Jan 2020 15:47:12 GMT

Closeup render.

Re: Transmission has a glowing rim when layering two objects with transmission

chris.bruinXRJUW — Wed, 08 Jan 2020 16:20:39 GMT

It is random each time the lighting/camera angle changes. There is never any consistency as to where they appear. I added a camera in the scene I sent you, using the HDRI that is included in the scene should show similar results to the RenderError.png included in the .zip