Lighting differences between 3.4 and 3.6

[amarlowe696]

I'm noticing some lighting differences between 3.4 and 3.6. It seems more like changes in the way GI is calculated or color mapping, but I'm not entirely sure. Overall, the scene is coming out darker. I tried messing with the adaptive light settings so see if that somehow had anything to do with it, but I didn't see any changes between Probabilistic and Adaptive when rendering this scene in 3.6. Were there any other changes to irradiance mapping and light cache, or any other lighting calculations that would be impacting my scene light this?

The lighting in scene attached is an HDRI in a dome light using a VrayHDRI. There is one fill light that is creating a highlight on the front legs of the stool. I even experimented with adjusting the shutter speed to match the 3.4 render, but lighting still didn't line up across the image.

Any help/advice would be greatly appreciated.

-Andrew

Update: I rendered something in an isolated studio environment in 3.4 and 3.6 and got the same looking result. I'm going to do some further testing with my scene.

[anthonyh]

i can`t tell the difference by eye but did you say no when loading your 3.4 scene into 3.6 when it asks you about the new settings ?

[amarlowe696]

Hi Anthony - it doesn't not mention anything about render setting adjustments which is why I'm reaching out about this. I get that some things change, but in the past we were warned about updating the render settings. One of the noticeable differences is the highlight on the top corner of the book and the lighting of the top of the stool. It may not seem like much, but in my line of work it can impact us greatly.

[svetlozar.draganov]

Does the difference appear olny on that scene or other scenes have the same behavior?
Can you try to add all render elements and check if the difference comes just fromone of them like GI or there are other discrepancies ?

[anthonyh]

hi,
i thought normally when you open a 3.4 scene in 3.5/6 it asks about updating to the spectral renderering thing ? maybe it`s older versions than 3.4 ?
anthonyh

[amarlowe696]

I did some testing with another completed scene with a similar lighting setup. I tried removing the glass from the windows, I tried changing from IR & LC to BF & LC, but I was still seeing lighting differences. It seems like it's related to GI calculations since the lighting passes seem to be the same, but the RawGI and GI elements have obvious differences in light.

I thought I would also note that the render times increased every time when rendering in 3.6 versus 3.4. Nothing insane, but usually a minute difference from what I've recorded. The images attached have the time recorded in their name. I realize the difference isn't huge, but if you save the images and flip between the two you'll see what i'm talking about.

[amarlowe696]

Bump. I know the changes are subtle in some scenarios, but I still think this is worth looking into.

[anthonyh]

the render time increase was already spotted in another thread, vray3.6 is about 10% slower for some reason, Vlado`s aware of it I believe.

[vlado]

Yes, we'll get it back.

Best regards,
Vlado