Light emitters behind a glass don't generate lens effects until I hide the glass object

[Alex_M]

I have an issue with lens effects not showing up until I hide a glass object. Please see the screenshots below. Trace depth in Global Switches is set to 20 and all glass materials have reflect and refract depths set to 20 as well. The lights in the small bulbs are separate objects with VrayLightMtl applied and Direct illumination turned on. This VrayLightMtl is not part of a Multi/Sub-Object material.

[vladimir.nedev]

Is this V-Ray ? I think you mistakenly posted it in the Vantage forum.

Greetings,
Vladimir Nedev

[fixeighted]

Weird...I tried this and it didn't appear to work, as you said, though after randomly trying various things it now does seem to work.
I'm unsure why, as I think the settings are mainly what they were when it did not work, so either it's flaky
or I got lucky with some specific tweak. Anyway, scene here https://www.dropbox.com/s/5cwa9a2j8u...LARES.max?dl=0 so maybe it'll help

[Alex_M]

Is this V-Ray ? I think you mistakenly posted it in the Vantage forum.

Greetings,
Vladimir Nedev

Sorry, you are correct! Can someone move the thread in the appropriate forum section or should I create a new one in Vray GPU for 3ds Max?

Weird...I tried this and it didn't appear to work, as you said, though after randomly trying various things it now does seem to work.
I'm unsure why, as I think the settings are mainly what they were when it did not work, so either it's flaky
or I got lucky with some specific tweak. Anyway, scene here https://www.dropbox.com/s/5cwa9a2j8u...LARES.max?dl=0 so maybe it'll help

Thanks, I'll check it out.

[yavor.rubenov]

Hello,

Overall the LensFx works purely on images and RGB data - it only cares about the intensity of a given pixel. If it is below the threshold it is ignored. So could you check the intensities of the lights behind glass - maybe since glass attenuates some of the energy the pixels there are below the threshold ?

Best regards,
Yavor

[Alex_M]

Hello Yavor,

I've placed regular spherical Vray lights in the bulbs and the problem still persists. The glass in my latest tests is not tinted, it's fully transparent so it shouldn't really affect the light intensity, but it still blocks the light as if it's heavily tinted. I measured the linear values of the pixels at the center of the bulbs and with a glass cover the pixel value is ~11 and without the glass it's ~96. This can't be normal, can it? Maybe the problem is somewhere else? Should I send the scene for inspection?

[npg]

Reflection takes energy away. Try with zero reflection.

[seandunderdale]

I had this issue a while back. In my instance, it was to do with the max ray intensity value, if I recall. Basically blurring a refraction enables the max ray intensity value, which defaults to 20. This means itll kill off all of your potential lens fx values. If you bump the max ray intensity up to say, 500, youll find the lens fx come back, but render times and noise go up.

[Alex_M]

Reflection takes energy away. Try with zero reflection.

Hi, npg . Thanks for the suggestion. I've just tried with pure black/zero reflections. No luck. The fully transparent and non reflective glass still takes away the majority of the light energy. I've made a quick test with the CPU renderer and there was no issues there even with trace depth at 5. Please see screenshots below.

I had this issue a while back. In my instance, it was to do with the max ray intensity value, if I recall. Basically blurring a refraction enables the max ray intensity value, which defaults to 20. This means itll kill off all of your potential lens fx values. If you bump the max ray intensity up to say, 500, youll find the lens fx come back, but render times and noise go up.

Increasing Max ray intensity a lot indeed solves the issue. Unfortunately, this is not a very good workaround as I end up with tons of fireflies. Why does glare work fine with the CPU render and default MRI values, but the GPU renderer does not and needs to be cranked way up? Is this by design?