PBR materials seem to reflect light from underneath and sides in shadow are to light
complete
Atlas Linden
Filed by Froukje Hoorenbeek
What just happened?
I'm making PBR materials for furniture. I upload materials directly as I made them in Substance Painter. But when I look at them in SL, they seem to reflect some light from the bottom. Also, the backs, that in the shadowside, are to light. Both look unnatural.
They are SL or firestorm problems, not visible in SP, and seem to come from the reflection of the roughness metallic. It can be fixed by making those areas on the roughness metallic darker in Photoshop.
But that is not a great solution. If I make them look as they should, and you fix this later on, I am stuck with too dark backs and bottoms.
What were you doing when it happened?
trying out PBR materials
What were you expecting to happen instead?
I expected the bottom of furniture to be darker, as the ground does not give light. I also expect the backs of furniture, to be darker than the parts that catch light.
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Atlas Linden
This issue is considered to be expected behaviour with the lighting from automatically generated reflection probes. Manually placed reflection probes will help remove undesirable lighting that you may be experiencing.
Dan Linden
Hi Froukje.
This should be looking less blue in the latest GLTF Maint 2 viewer at https://releasenotes.secondlife.com/viewer/7.1.3.7821226606.html
I'd like to take another look at the chair from the original report. Would you share a copy with me and Atlas Linden or send a link if it's on the marketplace.
Froukje Hoorenbeek
Dan Linden the less blue is really nice. Sending you and Atlas copies of the chairs inworld. Kind regards
Tia Biscuit
Gosh, I didn't even notice that till you pointed it out. I'm so hung up on the normals being more aggressive than I'm used to! Great spot Froukje! Hopefully, the devs can find a way around it!
Condamnante Resident
I'm using Firestorm alpha, because default viewer can't disable reflections afaik. Now, first image is the same material, left inside lighting (inside probe), and right is outside, no probes. Second image is the same, but reflections disabled. Shots taken at midday preset. Other time of days will make differences less noticeable...
Added a third image, maybe it shows better what's the issue (left inside probe at midday, right outside midday).
Kristy Aurelia
Condamnante Resident: That's just looks like the outdoor reflection probe (auto placed) reflecting the sky.
Condamnante Resident
Kristy Aurelia It's a post about reflections being broken, and I thought my images will help.
Zii Minotaur
Here's a picture of spheres in a black room with fullbright white ceiling - taken with the SL Viewer.
The rim lighting is what is causing lighting underneath objects.
I don't feel tech-literate enough when it comes to PBR shading to make truly helpful comments, but I'm concerned about the rim lighting being overpowering on dark objects.
That said, PBR lighting makes more sense when the whole scene is PBR. I do wonder if some apparent issues will resolve when more compatible content is available.
Kristy Aurelia
Is the reflection probe misplaced and not rendering the terrain, so the underground is equivalent to the sky? I'd try it in an enclosed room with a correctly positioned reflection probe that reflects the floor and not stuff under the floor.
Atlas Linden
The below comments have been copied from Jira: https://jira.secondlife.com/browse/BUG-234987
Atlas Linden added a comment - 16/Jan/24 10:31 AM
Hi Froukje ,
Are you able to supply the location of the content in SL or images of what you're seeing in both SL and SP? Alternatively, attach the content to this Jira or email it to either atlas@lindenlab.com or dan@lindenlab.com so that we can investigate the issue further
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froukje.hoorenbeek
Froukje Hoorenbeek added a comment - 18/Jan/24 3:43 AM
Hi Atlas,
these pictures are taken on my mainland plot, outside, in the new midday environment, with the Firestorm Alpha viewer. I focussed on the leather. I make mostly furniture and cannot control what environment they end up in, or what my customers do with reflection probes and such.
Apart from the obvious, a blue shine that makes the chair pink instead of red, this is what I noticed.
Light from underneath pictures 1 and 2: The red leather tub chair on the right is the chair with textures. The chair on the left is made with materials.
Back in shadow seems to light compared to front: I downloaded the new firestorm alpha viewer today and it seems less obvious now.
Leather tub chair in substance painter: as I made the materials in SP, soft1 front environment.
I'll leave the chairs out for a while, in case you want to see this inworld: http://maps.secondlife.com/secondlife/Marachia/160/75/23
Kind regards,
Froukje
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gwyneth.llewelyn
Gwyneth Llewelyn added a comment - 19/Jan/24 10:55 AM
How does it look like on the latest version of the official SL viewer? There are differences between how SL and Firestorm approach the rendering pipeline, you know. I'm not saying that they are "better" or "worse" — just, well, different. Different enough to cause what you're seeing in Firestorm but not on the SL Viewer, for example.
Here's a thought. Do you know what HDRI image is being used by Firestorm on their viewer? I understand that some content creators prefer to do their work using a "ground-less" HDRI, i.e. sky all around, because that way the object is uniformly lit (there are plenty of "all sky" HDRI images out there). This may avoid certain situations where an object is lifted from the ground and seen from below (imagine an arm being raised while wearing PBM-enhanced clothes).
Assuming that Firestorm Alpha uses exactly the same HDRI file as LL for its "new midday", then, of course, you should not see any differences between both viewers. But if the Firestorm team have slightly tinkered with the HDRI image — or, rather, used a different one — then it might explain why you are apparently seeing some light coming from below.
(Note: my first plausible explanation of what you're seeing was to ask your first at what height your sandbox was, when you took the attached pictures; then I saw your SLURL, which clearly shows they have been taken at ground level )
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froukje.hoorenbeek
Froukje Hoorenbeek added a comment - 20/Jan/24 2:06 AM
Hi Gwyneth,
I looked at this in the official viewer and saw the same thing, so it is not viewer-related.
I also tried the chairs on my platform first, and then moved them to ground level to make sure it was not because I had them high up in the air.
Kind regards,
Froukje