Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Yousef13 on 2022-12-30, 15:15:45

Title: Two instanced lights acting differently!
Post by: Yousef13 on 2022-12-30, 15:15:45
Hello

Attached is the render beside the setup for two instanced lights that appear different in the render
I turned off UVW maps modifiers and seemed to fix the problem, which made me more confused !!

Any ideas ?

Thank you
Title: Re: Two instanced lights acting differently!
Post by: aaouviz on 2022-12-30, 20:04:57
My first guess would be that the light is a different distance from the wall. Make sure they're both exactly the same distance from the wall they're casting light on.
Title: Re: Two instanced lights acting differently!
Post by: Yousef13 on 2022-12-31, 00:02:48
Quote from: aaouviz on 2022-12-30, 20:04:57
My first guess would be that the light is a different distance from the wall. Make sure they're both exactly the same distance from the wall they're casting light on.

the second image shows the result when turning off UVW map modifier while both lights are still in the same position, so no it is not the distance
Title: Re: Two instanced lights acting differently!
Post by: aaouviz on 2022-12-31, 20:22:11
Did you at least check?

Because the image with the mapping off still clearly shows that the light on the left wall is not quite as strong.

Turning off the mapping, thus changing the appearance of the material/object will definitely give different lighting conditions, so I don't 100% believe that your hunch is correct.


Or, simply try just delete the lights and make new ones.

Or, check your bump mapping, is the bump somehow creating the effect?

Or, is one of the lights slightly rotated?

There are many potential causes, I would say this isn't a bug but rather something within the scene has gone wrong which only you can fix.

Good luck, mate.
Title: Re: Two instanced lights acting differently!
Post by: Yousef13 on 2023-01-05, 12:50:29
Quote from: aaouviz on 2022-12-31, 20:22:11


Or, check your bump mapping, is the bump somehow creating the effect?


This was it, I don't know how the bump was doing this even though both sides were one object and one material but I turned off the bump and it was fixed
Thank you
Title: Re: Two instanced lights acting differently!
Post by: aaouviz on 2023-01-06, 09:31:26
Excellent, glad you found the problem.

Did you rotate the normal map, by any chance? Or did you use a uvw randomizer on it? As I understand we shouldn't be doing this, so this might be the reason...
Title: Re: Two instanced lights acting differently!
Post by: romullus on 2023-01-06, 10:23:31
You don't even need normal map for that, regular bump is affecting material's anisotropy too. If the bump texture has pronounced directionality in it, this can affect how light bounces back from the surface.