Shading bug behind glass?

[treddie]

Hi, again.

Here is an example of what looks like an Octane shading bug, or me making an incorrect PMC setting or something. Notice how the light is behaving differently on the surfaces when they are behind glass (no dispersion in this example), and when there is no intervening glass. The version on the left (w glass) is messed up. The highlights are reversed out...going dark when they should be going light as they face the light source. The image on the right (wo glass) is perfect.

The normals of both the car interior parts and the glass are facing in the correct directions.

[roeland]

Hi, again.

Here is an example of what looks like an Octane shading bug, or me making an incorrect PMC setting or something. Notice how the light is behaving differently on the surfaces when they are behind glass (no dispersion in this example), and when there is no intervening glass. The version on the left (w glass) is messed up. The highlights are reversed out...going dark when they should be going light as they face the light source. The image on the right (wo glass) is perfect.

The normals of both the car interior parts and the glass are facing in the correct directions.

Can you check in the kernel settings what the maximum depth is?

--
Roeland

[treddie]

Hi Roeland.

It is set to 16.

Update: I kicked it up to 32 just for the hell of it, with no change. Still the same problem.

[treddie]

The same meshes lit by a different environment does not cause the same problem. I will see if my original setup still causes it by relaunching Octane after this current render completes.

[treddie]

Roeland,

Referring to my last post, same problem with the original file.

If you want to see a file of just the problem areas, do you have an address I can upload the orbx to? It is too big for this forum.

[treddie]

Any clues yet, as to what is happening?

[roeland]

I don't really have an idea. Does the glass have Fake shadows enabled? Does the environment for which it doesn't render correctly have small bright highlights?

If you want you can upload the file on https://mega.co.nz/ so we can have a look.

--
Roeland

[treddie]

I uploaded an orbx package of just the bare essential surfaces needed to show the problem:
URL: https://mega.co.nz/#fm/sJA0wCbB
No password

The worst kind of programming problem I guess, seeing as how it only happens intermittently.

This is a v1.53.1 file.

Notice that the gray plastic areas on the far left not cast over by rays coming from the two glass pieces have correct reflections.

But there are two areas where the reflections are messed up:
1. When viewing the gray surfaces THROUGH the glass.
2. Those gray surfaces NOT seen through the glass, but BELOW the glass pieces. In other words, these areas are still interacting with the glass, even though the glass itself is not between the viewer and the gray parts.

Happens when Fake Shadows is on or off, PT or PMC. Max Depth of 32 has no effect.

Thanks for taking a look!

[roeland]

The link is just redirecting to the login page, is this file still up?

--
Roeland

[treddie]

Try this one:
https://mega.co.nz/#!5YYW1K7L!0WddMaeUD ... bDwdRWBAbg

I'm just posting it here since there is no sensitive information in the file.