GPU production render issues

[rusty_sena]

Hi all,

On the left is a low res (1k pixels tall) and on the right is a high res (4k pixels tall). Both were done as production renders using the GPU. This is using the latest versions of Modo and Vray. I want the more pronounced reflections as shown on the left. However, when I up the resolution, the reflection quality changes as seen on the right. I'm referring to the reflections on the wood floor. Note - the only thing that has changed is the resolution - no other settings were touched. Should I be changing settings for high res renders? This one is giving me a headache. Please help as I have a lot of these renders to do and I can't have this visual difference happening when I want to do high res renders. Ignore the crappy color as I will be doing more editing in post. For the record the only render outputs in the shader tree are final color and cryptomatte.

Thank you,
Rusty

[vladimir.nedev]

Do you have a very fine bump map on the floor ?

Greetings,
Vladimir Nedev

[rusty_sena]

Yes, I do.

[vladimir.nedev]

If you can replace it with a normal map, this will most likely fix the issue. The other option is to disable it.

Greetings,
Vladimir Nedev

[rusty_sena]

Got it. I don't have a normal map so I'll just have to turn it off. I don't think it's critical to have it. Do you think I'll just have to adjust my reflection settings to compensate for the fact that I no longer have a bump map? I'll try it out either way when I get back to the office but thought I'd ask. Thank for the response!

[vladimir.nedev]

A very fine bump map basically turns into glossiness.
In V-Ray the bump calculation is based on texel/pixel ratio - this allows us to load a mipmap with the lowest resolution possible.
This causes the apparent change in glossiness you see.

Greetings.
Vladimir Nedev

[Robert]

Here is free tool that converts high maps in normal maps, if you need: https://boundingboxsoftware.com/materialize/

[rusty_sena]

Question: Does the level of detail decrease for a Vrscan at a distance? For example when the camera is close to an object the detail is there. But when at a certain distance that same object seems to lose it's texture detail. I don't know if it's really just a resolution issue or not. I've rendered my scene at progressiveily higher levels to some extent and can't see the difference - the Vrscan texture seems to lose a lot of detail. Is this normal? Can I change this?
Thank you!