[BUG] Bump mapping problems

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u3dreal
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[BUG] Bump mapping problems

Post by u3dreal » Sat Nov 11, 2006 11:57 pm

Hi all, Hi Nick,

while optimizing my exporter i came across some bumpmapping bugs..

Image

From left to right specular diffuse plastic metal

when taking a closer look there seem to be two bugs..

(1) The bumpmapping of the specular material seems wrong most visible on the sphere and the plane

(2) The smoothing seems not to be working correctly most visible on diffuse and plastic... you can see the faces there

OK hope this helps here is the scene...

Download Scene

cheers

u3dreal ;)
Last edited by u3dreal on Sun Nov 12, 2006 4:38 am, edited 1 time in total.

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Kosmokrator
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Post by Kosmokrator » Sun Nov 12, 2006 3:03 am

u3dreal i can see your image or download the scene...please check the links...thnx
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OnoSendai
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Post by OnoSendai » Sun Nov 12, 2006 3:20 am

Thanks u3dreal,
the bump mapping /shading normals bug is a known problem.
Not sure about the other one, it's kinda hard to see what the problem is in your image.

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u3dreal
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Post by u3dreal » Sun Nov 12, 2006 4:48 am

Ok the first one is most visible here

Image

the mapping seems to be applied in two directions z and y ...
You can see this on the two circles one at the top of the sphere and another one on the front ... also the mapping of the plane and the
box seem to be strange the plane is only in x direction not in z as it should ..on the box you can see that there are no squares on the frontside only lines ...

here is an image where i tried to mark the points...

Image

hope it's getting clearer now...:D

The link for the scene should also work now maybe you can get the clue from there ..

i will try to make a closeup of the sphere maybe without transparecy..

cheers

u3dreal ;)
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StompinTom
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Post by StompinTom » Sun Nov 12, 2006 5:10 am

wait... specular materials can have a bump map now?

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Post by OnoSendai » Sun Nov 12, 2006 5:11 am

yes tom :)
makes a lot of noise however :P

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Post by StompinTom » Sun Nov 12, 2006 5:14 am

siiiick... i was supposed to do some work today but... [boots blender].

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Post by Kosmokrator » Sun Nov 12, 2006 6:10 am

ok u3dreaL now i see your pics.....thnx!
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u3dreal
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Post by u3dreal » Sun Nov 12, 2006 7:24 am

Ok here it is pretty obvious that something is wrong with the specular bump..

Image

both spheres have the same mapping and bumpmap..
actually they are copys..

Although it is different right now...:roll:

cheers

u3dreal ;)

PS Nick if you need the scene let me know..

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Post by Kosmokrator » Sun Nov 12, 2006 7:33 am

its a known bug u3dreal.....bump map kills smooth... :wink:
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u3dreal
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Post by u3dreal » Sun Nov 12, 2006 7:45 am

Kosmokrator wrote:its a known bug u3dreal.....bump map kills smooth... :wink:
Not the smoothing problem... isn't bump map different form the diffuse ?????? Is this really so hard to see...OK

Here is the same scene with plastic material ..

Image

Obviously the bump looks a little different from the specular..
agree ???

The smoothing problem only seems to be in the diffuse code..as the pure phong with black diffuse renders fine....

The small facets are in the bump map so this is correct..

Nick you agree ??

cheers

u3dreal ;)

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OnoSendai
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Post by OnoSendai » Sun Nov 12, 2006 7:48 am

Let me explain in more detail...
When bump mapping is enabled, the underlying, pre-perturbed normal used is the geometric normal. The shading (interpolated) normal is not used.
This is incorrect, and will be fixed at some point.

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Post by Kosmokrator » Sun Nov 12, 2006 7:51 am

oohh yes u3dreal....now i catch it!im sorry..... :oops:

nick yes please fix this micro-bugs.... :wink:
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zuegs
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Post by zuegs » Sun Nov 12, 2006 11:39 am

yes i can see it too, the uv-coords for bump-map on specular materials are wrong / lost :cry:

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u3dreal
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Post by u3dreal » Sun Nov 12, 2006 12:17 pm

OK

thanks guys..

cheers

u3dreal ;)

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