Have you ever noticed that the strength of an image based bump map varies according to the resolution you are rendering at??
The higher the resolution the softer the bump map. So, if you wanted to achieve a certain bumpiness and you doubled the resolution, you would have to double the slider value too.
Does anybody knows why this happens?
The render is based on pixel units rather than actual blender units.
I have noticed that (compared to 3DsMax) Blender’s implementation of bump map is poor. So poor that everytime I try to use it I feel like I am wasting my time.
Blender has some problems with procedural bump maps, but normal maps and image bump maps work perfectly well (except for this minor issue I´m posting). If you are thinking on using a procedural bump map you should bake it to a texture.
Actually, you have that back to front. Blender’s image based bumping is possibly the poorest I’ve seen in any 3d app.
Just to clarify things a little, I made a detailed post on blender.org regarding this, but it was so long ago that I can’t find it now. I issued a challenge for anyone to try and recreate this image with the internal renderer:
I used Yafray for this. It took something like a minute and a half to render. If you want to try making something like this in blender, here is the texture I used:
http://img.photobucket.com/albums/v27/M@dcow/geob04.jpg
I urge you to try and replicate this in blender, then you’ll understand just how bad blender is at image based bumping.
how many repeat in x and y and what value of NOR did you used
i’ll make a test and let you know!
Salutations
I repeated it about 20 times in both I think. I also can’t remember what Nor value I used, but I can honestly say it doesn’t matter though, as I’ve just tried it with Nor set to 25 (max) and it still doesn’t look anywhere near as bumpy as the yafray render.
i did a test and results are more or less good
i use an ordinary lamp in this model may be with a beam it would work better!
bledner is fast but results definitively so so!
yavray in this case seems to be overlit - usually it’s the inverse here i did not change the light intensity
results are a bit better but the 3D effect is not very good in any of them!
mind you i have a bug on my video card and it may influence the results
i know that normal map don’t work as long as this bug is not resolved
and i hope it will be soon
if you had this file i would like to make a rendering test to see if the bug on my video card is influencing the effecton bump map too that would be nice - at least i would know it for certain
That was fun LOL
SAlutations
Here is my bump test using the provided map. Rendered with the internal render engine. OSA = 5 CatRom 0.5 AO Default with samples bumped up from 5 to 7. Took 4:20 seconds on my single core 1.92Mhz AMD.
Here’s two tests I made, The second one is yafray.
Your edges look pretty crisp, I tried catrom with 8 oversampling and it didn’t do anything.
Do you need to composite ao to get the edges bumped?
I thought ao disregarded bump maps.
Also with this I had a lot of troubles getting it to map to uv,
I had to orco and spherical map it, but I didn’t unwrap it. 
I thought that the problem with Blender internal was that the bumps were just weak,
but with a sphere it’s pretty apparent that the edges fade out.
Although I got fancy with a skybox and reflections, there’s no atmosphere.
I wonder if this is carried out with displacements as well?
Probably with some severe lighting it would show that the displacements in
the center of the object are amplified to a higher extent than the edges maybe.
I thought that the problem with Blender internal was that the bumps were just weak,
but with a sphere it’s pretty apparent that the edges fade out.
well, you can bypass that by turning mipmapping off in the texture buttons, but there will still be issues with the results you get.
Also, try turning the filter setting down in the texture, and activate ‘Full OSA’ in the material buttons, should get you closer to the desired result.
I had to orco and spherical map it, but I didn’t unwrap it.
Hehe, should have mentioned that’s what I did as well, so for this test, it was absolutely correct.
LOL I guess it’s because of the 20 xrepeat on 32 uv faces eh?
“Bumps are rendering all grainy all the sudden!”
Thanks I’ll try full osa in the material, I never noticed that one,
usually I turn off mippmapping, because I read it’s better for texture resolution,
but I was struggling with the whole orco spherical mapping thing. 
EDIT I made this test with Blender Internal,
with AO it only took 70 minutes to render out!
All joking aside, the bumps are very weak, and spindly,
although the norm value is up to 25, it does look a lot better than no contour bumps, thanks madcow!
i did not know tht mipmap had such an effect on the texture
never read that before
but i’ll take note of that one
is thre an angle best suited to get the best results from bump or normal map?
Thanks
I took another stab at it.
This one looks a little bit clearer, but it still has that soft blur on top. I am in full agreement that the internal blender bump map rendering needs some help.
I played around a bit with the math. I set the single sunlight to 0.5. I turned down the filter on the texture 0.1. I turned on full OSA for the material. I set the camera lens to 18 then used SHIFT-F Wheel to fly back in an reframe. I upped the render size to 800x600. I adjusted the shadow falloff in the AO to 5.2, down from 10. I also used an ICO sphere and no smoothing on the mesh.
