Odd Splotches With Normal Map

[tommygdawg]

Hey all,


I just fixed up my gamma settings for a scene I've been working on and suddenly I'm getting some strange issues with the normal maps. In various places, depending on how the light falls, I get really weird bright and dark splotches.

Original render before correcting gamma settings:

Render with corrected gamma and normal map:

Render with corrected gamma and no normal map:


Everything with the scene is pretty standard. I've set my 3DS Max Gamma to 2.2 and my input gamma on textures to 2.2 and have left the output at 1.0. All of my textures are set in the material editor to use the default system gamma, in this case 2.2. Anyone have any ideas what might be going on here?

Thanks!
- Tommy

[tashko.zashev]

Hi,

Normal maps should not be gamma corrected.
You can add a Color correction node (between the texture and V-ray normal map) and set 2,2 in the gamma filed. This will give you correct bump result.

[Slazzo]

Normal maps should not be gamma corrected.

Does it make sense to correct and bump/reflection/glossiness maps also?
What if the normal map is not 8bit format, like png, exr etc. do they have to be corrected?

corrected - I mean using the Color_Correction with the gamma 2.2

[trixian]

This still confuses me.
Should one not just load the bitmap with the specified 2,2 in the load dialogue?
I wish there was a way to let us see the gamma correction as a view LUT for material editor previews etc, but leaving the map unaltered. This is obviously a shortcoming in 3dsmax, but it would be awesome if vray had some way to sneak around this limitation.

[svetlozar.draganov]

Does it make sense to correct and bump/reflection/glossiness maps also?
What if the normal map is not 8bit format, like png, exr etc. do they have to be corrected?

corrected - I mean using the Color_Correction with the gamma 2.2

Bump/reflection/glossiness maps shouldn't be gamma corrected as well - they should be loaded with gamma 1.0.
Non 8bit formats are not automatically gamma-corrected by 3DSMax - they usually do not have sRGB-profile applied hence they don't need gamma-correction.

[Deflaminis]

Hi,

Normal maps should not be gamma corrected.
You can add a Color correction node (between the texture and V-ray normal map) and set 2,2 in the gamma filed. This will give you correct bump result.

It used to be (a long time ago) that the color correct node would really slow down renders in huge scenes, is that still true? Is there a benefit to using the color correct vs. overriding the import gamma on the texture slot itself? Does it make the most sense to use the vrayhdri with a regular map plugged in since it now has gamma controls? (and it renders faster as posted by vlado here: http://forums.chaosgroup.com/showthr...i+supports+jpg)

Sorry for all the questions but I've wondered about this for a while and this is the perfect time to ask.

[vlado]

It used to be (a long time ago) that the color correct node would really slow down renders in huge scenes, is that still true?

Yes, it is. Best to avoid it, if this is the only purpose that you use it for.

Is there a benefit to using the color correct vs. overriding the import gamma on the texture slot itself?

Using correct import gamma is better.

Does it make the most sense to use the vrayhdri with a regular map plugged in since it now has gamma controls? (and it renders faster as posted by vlado here:

This comparison is only valid if you use the Bitmap Pager (which I don't really recommend either). You can still use VRayHDRI if you wish, but if this is the only purpose you are using it for, maybe it's better to stick to a Bitmap texture.

All in all the simplest and fastest way is to set the correct import gamma in the Bitmap texture.

Best regards,
Vlado