Isotropix Forums

issue with Normal map

General Discussion about Isotropix and CG related topics

Re: issue with Normal map

Unread postby ayanik » Sat Jul 11, 2020 7:02 pm

Hi Karen I've attached the file below.

I didn't do anything special with it. When you use the Refinement Sample Count setting in the pathtracer settings you activate the Adaptive AA sampler. This automatically distributes the samples.

In your image you probably don't have much light samples which might be the cause of some fireflies. The HDRI I used is an environment from the new Corona 6 sky system which I used with my sky rig. I believe your issue comes from a too low sample count of your light or maybe something else.

I've attached the project file without the HDRI and the Megascans asset below. Replace the paths with your own paths and make sure the color spaces are Linear - sRGB for the Diffuse texture, because the diffuse jpg's aren't Linear.
Attachments
concrete_karen.project
(58.74 KiB) Downloaded 20 times
ayanik
 
Posts: 89
Joined: Wed Nov 26, 2014 9:10 pm

Re: issue with Normal map

Unread postby Karen_Jonhson » Thu Jul 30, 2020 5:10 pm

Thank you for the file.
After a lot of work, everything has led back to square 1: there is an issue with the normal map.
More precisely: This combination holds the key to the issue: [normal map] + [distant light / hdri] shining on the reverse side of the normals.

The ceiling is part of a room. Refinement maximum sample count in raytracer with 512 has helped with one grid.
HDRIs and Distant lights are part of the problem, while the other types of lights don't seem to cause this issue (I've tried several combinations).

The final check (after a lot of work) was with a dark room and only one distant light. When the normal map is connected, I get clear white lines in the dark, when it's not, there aren't any.

This is quite unusual. If you have an idea of what is really going on I'll appreciate it.
Attachments
open_box.JPG
room_viewport.JPG
distant_exposure_5.JPG
Karen_Jonhson
 
Posts: 27
Joined: Fri Apr 03, 2020 12:24 pm

Re: issue with Normal map

Unread postby Karen_Jonhson » Thu Jul 30, 2020 5:25 pm

here is the room
Attachments
geo.zip
(1.22 KiB) Downloaded 17 times
Karen_Jonhson
 
Posts: 27
Joined: Fri Apr 03, 2020 12:24 pm

Re: issue with Normal map

Unread postby paq » Fri Jul 31, 2020 7:25 am

The geo here doesn't help to showcase your problem. Without any normal maps here's Mantra result (1 distant light, no gi bounce, default principledshader). You have light leak everywhere, adding a Nmap and you get shining walls (not the ceiling in this case, maybe it's a question of light orientation) .

Try at least to add a proper thickness, those single faces / half inverted normals will only gives you troubles in many render engine.
Attachments
HouSSgeo.jpg
User avatar
paq
 
Posts: 379
Joined: Fri Jan 25, 2013 11:33 pm
Location: Montréal

Previous

Return to General Discussion
cron