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Bump Blend Banding
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They are retained here for archive purposes only.
Bump Blend Banding // New Users
Post by johnhoward // Apr 11, 2008, 3:47pm
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johnhoward
Total Posts: 231
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I have a smooth curved wall and above it another identical wall except that I have applied a brick texture and a matching bump map to the upper wall.
I have rendered in VRAY with global illumination and note that even the smooth wall has noticeable large bands in the gradient from light to dark, but the textured wall has an absurd gross line of demarcation between the light and shadow sides - no real blending at all.
Is there a setting to adjust this - something that will tell VRAY to make smaller bands and thus a finer, more realistic gradient blend?
3 attached JPGs show the render, a screen shot of the VRAY setting in the stack, and a screen shot of the texture settings in the material editor in the stack.
Thanks for any clues.
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Dell XPS 410 Dual Processors - Vista Home 32 bit - NVIDIA GeForce 8600 GTS - TrueSpace 7.51 |
Post by splinters // Apr 11, 2008, 9:21pm
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splinters
Total Posts: 4148
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Did you use the smooth setting in the model side ME? It is on the left side of the old ME-looks like an orange sphere.
Or the smooth normals tool in the workspace main toolbar, near to the UV tools.
Also, your model looks to be faceted, how many sides does the cylinder have? Personally, I choose 32+ for a smooth effect. If closeup-many more than that. |
Post by Jack Edwards // Apr 11, 2008, 11:44pm
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Jack Edwards
Total Posts: 4062
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I agree with Splinters, you need to smooth the normals and increase the resolution on the mesh. Also there's a limitation with VRay where you have to have direct illumination for bumpmaps to show. Unfortunately bounced light is unaffected by bumpmaps. |
Post by johnhoward // Apr 12, 2008, 6:33am
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johnhoward
Total Posts: 231
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Thanks for the replies. Things are progressing from bad to weirder.
The curved wall had about 40 segments and applying smoothing had no effect.
I replaced the curved wall (which started flat and was curved using the "bend tool") with a cylindical tower with 500 segments (see cutaway screenshot) and applied smoothing as you suggested.
The original problem remains (very sharp, unrealistic line between light and shadow) and a new weirdness appears. Note in the aerial screen shot that the directional light covers a large area (size is set at 100), but when it hits the cylindrical wall, it acts like a narrow spotlight illluminating only the upper wall.
Then, for added weirdness, the VRAY render treats that upper wall as shaded with a rather grainy shadow. |
Post by daybe // Apr 12, 2008, 7:00am
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daybe
Total Posts: 562
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What happens if you put a direction light facing the opposite direction, turn shadows off and also reduce the brightness. Maybe this will help |
Post by trueBlue // Apr 12, 2008, 7:53am
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trueBlue
Total Posts: 1761
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Can you post this scene as is in your last post? |
Post by johnhoward // Apr 12, 2008, 8:20am
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johnhoward
Total Posts: 231
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Daybe,
Here is the result of that experiment - in the work view, objects appear dark and in the render (overlayed) they appear with only the bluish environmental light - the directional light (now pointing away from the scene) seems to have no effect. |
Post by Jack Edwards // Apr 12, 2008, 8:29am
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Jack Edwards
Total Posts: 4062
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Ahah, that would be part of the problem.
Directional light = D3D
Infinite Light = VRay. |
Post by johnhoward // Apr 12, 2008, 8:55am
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johnhoward
Total Posts: 231
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TrueBlue,
I am attempting to send RsScn as requested. Zip file is 16MB and won't upload. Keep getting "Webpage can't display" message after several minutes of uploading.
Now I have to leave. Back in a few hours and will try again. Thanks. |
Post by johnhoward // Apr 12, 2008, 5:29pm
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johnhoward
Total Posts: 231
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I have now attempted to send the RsScn file a half dozen times and each time the little "Manage Attachments" window sits there while my modem flashes for about 4-5 minutes, then the window says it can't display (see JPG below) and the modem stops flashing.
In an attempt both to reduce the file size (didn't work) and to simplify the problem I have run many experiments and learned this much for sure:
a) Number of segments is irrelevant - I've tried as high as 500
b) smoothing doesn't help, and in fact seems to produce uneven banding itself (see JPG below)
c) type of light is irrelevant - I tried a spotlight - exact same results
Infinite lights have no shadows, so not useful to me
d) global illumination irrelevant - I tried photo, color only, and none - same results
I could send low res copies of the texture, bump, and specular maps if you would like to experiment with them. Currently they are around 3MB, so too big to send as is.
Thanks for any clues.
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Who decided I was a "senior" member? I still don't know what I'm doing. |
Post by johnhoward // Apr 12, 2008, 6:24pm
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johnhoward
Total Posts: 231
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UPDATE
I have eliminated the bump map and added a normal map. With the normal map, things are almost normal. So now I am sure that the bump map is the main problem. I do not fully understand the two, so need to do more homework.
But if I understand bump maps, they are something I want to use, and the TS controls appear to limit me to either bump OR normal, but not both.
Confused. |
Post by kena // Apr 13, 2008, 6:58am
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kena
Total Posts: 2321
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Who decided I was a "senior" member? I still don't know what I'm doing. hehehe 120 posts decides that. did you try rendering your bumpmap in LightWorks? I think that normal mapping works in Workspace best and bumpmap works best in Model with LightWorks. |
Post by johnhoward // Apr 13, 2008, 2:38pm
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johnhoward
Total Posts: 231
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I did try bumpmap with lightworks - same bad results (actually worse).
Rule for now: On curved surfaces: bump map bad / normal map good.
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So "senior" members are the dummies like me who had to ask the most questions? What a let-down. I was looking up to these guys and they all turn out to be one of me. |
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