Different results/normals when rendering in very high resolution?

[markus_s_cg]

Hi!

I'm experiencing some weird differences on my render, depending on what resolution I'm rendering in. The image on the left was rendered originally at 8000x10000 pixels. The image on the right was rendered at 4000x5000px. Both examples are just a cropped out portion. On the high-res image I get some strange artifacts in the seam, the glossiness seems higher on the skin, and there are some pixels on the hair that appeared black in 32 bit, and white when converted to 8 bit. I'm experiencing the same issue both in max 2018/vray 3.6 and 2019 vray 4.02.04.
The material uses tangent space normalmap for details,different udims for the head and body, and the alsurface shader for the skin. Do you have any Idea why the results are different when rendering in higher resolution?

[markus_s_cg]

Ok, this is weird. Iv'e been doing some digging and found some issues with the glossiness/roughness map. At first I put it into the diffuse channel in vray and saw some strange things in the diffuse render element. I also tried switching to scanline, rendered with a simple material, no lights. The result is the same here. The texture has some kind of halo causing all sorts of seams and problems. If I load the map in a new bitmap slot I don't get the same problem, but I don't understand why the old one turned out like this?

[markus_s_cg]

Btw, I started looking into Vray HDRI nodes as a replacement for 3dsmax bitmap node. It says in the doc it can load udims/uvtiles but you need to use tags. Where exactly do I put the tags? Is it recommended to use this instead of 3dsmax built in multitile node?

In my case the texture is named with *u1_v1.png and *u2_v1.png

https://docs.chaosgroup.com/display/...materialeditor

[markus_s_cg]

Btw, I started looking into Vray HDRI nodes as a replacement for 3dsmax bitmap node. It says in the doc it can load udims/uvtiles but you need to use tags. Where exactly do I put the tags? Is it recommended to use this instead of 3dsmax built in multitile node?

In my case the texture is named with *u1_v1.png and *u2_v1.png

https://docs.chaosgroup.com/display/...materialeditor

oK, nevermind about the <tags>. I figured it out. I'm guessing this won't work if you need to send bitmaps with a job to backburner either...?

[markus_s_cg]

Things seem to be going a little smoother now, except I have two buckets that are stuck for a very long time in the hair region where I had artifacts before. I'm not sure how long I should give it. It has been close to 2 hours now.

[markus_s_cg]

Ok, I tried to cancel it but even after pressing cancel, stop and closing (X) the frame buffer window the render window in max keeps going, and it looks like I'll have to kill max from the task manager. Could this be a bug in Vray?

[stevesideas]

Did you ever solve the normals issue? I think I'm experiencing the same thing whilst rendering a hi-res image.