topic Re: Problems resizing/editing normal maps. in 3ds Max Forum

Problems resizing/editing normal maps.

ericbrochu — Sat, 08 Feb 2020 23:07:35 GMT

Okay so I'm trying to render out some 4096x4096 normal maps with the intention of downsizing them to 2048 or less, but any form of editing or just resizing will break how it displays in 3ds max. I did research this a bit and found that I needed to re-normalize the map using nvidia's normal map filter plugin for photoshop. I run the filter with 'normalize only' checked but it still breaks how it's displayed. The attached image shows two copies of the same model using the same material settings, the only difference is one is using a downsized map that I supposedly 're-normalized'. This a top view of a helicopter toy I'm working on for a virtual pinball table. What am I missing? Am I doing something wrong? I'm using an older version of the plugin on my older work station since I can't seem to get a new release to work on my new work station without it just crashing PS when I try to use the filter. This model does use symmetrical UV's but I have the same issue with other models that don't use symmetry.

https://us.v-cdn.net/5021068/uploads/editor/as/3lrhjyww1nsw.jpg

Any input would be appreciated.

Re: Problems resizing/editing normal maps.

Diffus3d — Sun, 09 Feb 2020 09:20:18 GMT

Hello @ericbrochu ,

I don't think you need to re-normalize anything... are you altering the size in photoshop or gimp? Can you post a scene with part of the model?

If I had to guess I'd say that gamma correction is causing you headaches. If you go to Rendering->Gamma/LUT Setup and uncheck "Enable Gamma/Lut Correction" does it magically start working? (You may need to rebake the original normal map.)

Best Regards,

Re: Problems resizing/editing normal maps.

ericbrochu — Sun, 09 Feb 2020 14:08:03 GMT

I'm altering the size in photoshop, I go --> Image size, reduce from 4096x4096 to 2048x2048, saving as png.

Disabling gamma/lut correction did make it display correctly again, but is this something I should be concerned about? Would it not potentially display incorrectly in a game if it uses gamma correction?

Re: Problems resizing/editing normal maps.

ericbrochu — Sun, 09 Feb 2020 15:47:52 GMT

When you say I may need to re-bake the original normal map, do you mean that I need to re-bake it without LUT/Gamma correction? Can you elaborate please?

Also let me express my gratitude for your input, this has had me really scratching my head trying to figure out what's going on, scoured the internet for hours researching potential causes before finally posting here (and on polycount).

Re: Problems resizing/editing normal maps.

10DSpace — Sun, 09 Feb 2020 15:51:43 GMT

Hi @ericbrochu

If you want to work in what is called a linear workflow with gamma correction, then the other option is to leave gamma/lut correction enabled in max, but make sure that when you load the normal map in max you use gamma override in the bitmap load dialogue (see below):

A video explaining why a linear workflow is desirable for photorealistic rendering is here:

https://www.youtube.com/watch?v=Y3s0mxOxPCM

Hope this helps.

Re: Problems resizing/editing normal maps.

ericbrochu — Sun, 09 Feb 2020 16:01:09 GMT

Thanks, appreciate the info.