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Author Topic: Bump mapping nightmare (56k Warning)  (Read 3400 times)

Suppastar

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Bump mapping nightmare (56k Warning)
« on: September 25, 2008, 12:45:17 am »

Ok......


Well, I'm messing around with normal mapping (Bump mapping) and no matter how much I try it never wants to bump map on the X axis?

Here is an example:



As you can see the Y Axis renders just fine, while the X axis acts like it wants to, but it wont. Also why are there circles in the Bump map edge?


http://i60.photobucket.com/albums/h30/komodo33/help2.jpg
Here is the same model as above but the lighting was changed in the other direction, as I thought: "Maybe the light was making it render funny", nope. Even without a light in the scene it still does it as well.

http://i60.photobucket.com/albums/h30/komodo33/helpfull.jpg
Here is the same render as above but with the diffuse map on it, it shows even better that it just stops when it tries to render on the X axis.


Here is the bump map

http://i60.photobucket.com/albums/h30/komodo33/4351-bump.jpg

Also the Scene view showing the Bump in all it's glory.
*WARNING* image below is a 1024 X 768 desktop Print screen.

http://i60.photobucket.com/albums/h30/komodo33/544.jpg


EDIT: Here is new Bump map I was just thinking maybe the bump map was messed up, nope this is even worse.

http://i60.photobucket.com/albums/h30/komodo33/notnormal44.jpg
« Last Edit: September 25, 2008, 12:57:51 am by Suppastar »
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CowTail

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Re: Bump mapping nightmare (56k Warning)
« Reply #1 on: September 25, 2008, 03:58:20 am »

Looks fine to me. What you're seeing is the lighting effect and there's nothing wrong with it. Apparently you didn't change the lighting angle enough while you were trying to figure it out. The "circles" are just the portions of shadow that you see as a result of the uneven lines in that bump map. If they were straight lines and without that blurred looking border then it wouldn't look so weird.

To see what I mean, just apply the texture to all the faces of a cube and arc rotate around in object mode (if you have shaders enabled then you can see the effects without rendering), and do render previews.
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Steve

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Re: Bump mapping nightmare (56k Warning)
« Reply #2 on: September 25, 2008, 05:56:27 am »

Your new bump map has some fairly extreme derivatives.  It looks like it's an image of a lit surface with shadows from a light.  That makes strange bumpmapping math, not exactly something you'd find in the real world.

Heights field like your first bumpmap work better but you can't push them to extremes.  Try a more gradual transition form black to white and it should reduce the artifacts.  Those circles and double lines at the edges are due to the sharp change in the slope of the height.   The bump color is solid white then abruptly change to a straight slope to black.  This discontinuity in the slope shows up as the ringing noise artifact you mention once the bumpmap filtering is applied.

Here's your original bumpmap material with which has been modified by a gaussioan blurr of 3 and an image with two materials, one with your original bumpmap and the other with the gaussian.  The second is much smoother.  Both have a bump weight of 45.  Also notice that the blurred one appears to have less height.

(And yes, the reason that the bump map effect isn't therei n the X direction is because that's the way the directoin of the light.)
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Suppastar

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Re: Bump mapping nightmare (56k Warning)
« Reply #3 on: September 25, 2008, 06:46:08 pm »

Thank you, Steve!


That fixed my problem, now my only question is there any tutorials on how to make bump maps the effective way, as learning from messing around with Paint.net effects and stuff doesn't work like you all that well.


Is there any programs that can generate Bump maps from a texture? If not could someone just show me how to do it properly.



BTW: The image is the same lighting as before but with a properly done bump map it, show the Bumps through out. :)
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hihosilver

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Re: Bump mapping nightmare (56k Warning)
« Reply #4 on: September 25, 2008, 10:45:17 pm »

There is not a program that makes bumpmaps for you, and that makes perfect sense.  Bumpmaps are grayscale images that tell the program how much height and depth to simulate.  You can't get this information from an image.  Something in an image may be colored black, yet be extruded outwards.  For example, those tiles are a darker color, but the white tiles have the same height, so in the bumpmap they're both displayed as white.
A program can't guess at this, all it knows is the color of the pixels.  So what you want to do is do it yourself.
To do this, use a program like photoshop or Gimp, convert the image to grayscale and edit it yourself, or you can paint it in yourself with different brushes.  The darker something is, the more it will appear to indent, and the whiter it is the more it will appear to extrude.  It's all a matter of knowing what's going on in your texture and portraying this in the bumpmap
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Steve

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Re: Bump mapping nightmare (56k Warning)
« Reply #5 on: September 26, 2008, 06:19:55 am »

Nice pic, Suppastar!  The way you get good at most things is to keep asking how you can make it better.  Bit by bit you become an expert.
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