Bump Map
IceDragonArt
Posts: 12,548
in New Users
So I have been playing around a bit with colors and textures and have figures out what some of the different things are but what exactly is a bump map? I understand what the diffusionand the specular ones do but can't quite figure this one out.
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When a bump map is applied to a surface, it tricks the rendering engine into thinking that the surface at that point is tilted. Darker settings indicate the surface angles down, lighter settings make it appear to angle up. The surface isn't actually changed, the bump map just fools the rendering engine into thinking it has been.
On the other hand, a displacement map does change the surface. It physically alters the geometry of the surface during rendering by raising vertices on the surface and creating a slightly different mesh.
Okay thank you!
Bump is easier on the system too, compared to Displacement. As it does not actually manipulate geometry. Some rendering engines are more picky about displacement maps than others. This could be the settings or just how dense the mesh is for it to apply proper displacement. There is also normal maps, which unlike bump maps work better from more angles. However they still don't cause physical displacement so they are easier on the ssytem to calculate but a bit harder to throw together in photoshop.
A lot of times people just make a bump map from the diffuse texture(turn it from color to grayscale). And it can work decently enough.
Thank you. I think I understand and will play with this a bit to see if I can apply what you guys have explained. Thank you for the help!
Hiya, silverriverjewelry. In case you are interested, there is a thread in this forum, about 3D terminology... http://www.daz3d.com/forums/discussion/46/glossary-of-terms-for-those-new-to-digital-art-and-daz-3d#latest
I put it together back on the old DAZ forum (when I went by the username "Lordvicore"), there are tons more new terms now, but mostly (aside from the handful of now long dead links)... (Sorry, I'd remove those, but I can't edit that thread anymore since it was migrated by DAZ)... But anyway most of the terms are still very relevant. Also, my apologies for the corny attempts at humor that are contained within.
Awesome thank you McGyver! And I love corny attempts at humor please don't apologize!
Wow that has a huge amount of information. Thanks for sharing it!
Here's a quickie example... on the left is a basic DAZ render *without* a BUMP file. Note also that sometimes the supplied bump file that came with some model doesn't cut the mustard for you, for whatever reason(s). There are other problems too like sometimes a model is too "pointy" and has too many "sharp edges" but anyway we'll just concentrate on the BUMP file.
So you take a sample color from your basic palette, and make a blank file with that color as the background. Here I chose a caramel like, light brown. I added some noise with an artistic filter, pixels sprayed across the image in a random pattern, and I saved that to disk as my freelance, new "texture" file. Then I reduced the color saturation to nothing (gray scale) and I saved that as my "bump" file for this image. Then before rendering the test "scene" I specified my new texture file and my new "bump" file in the Surfaces pane in DS, after selecting the areas in question with the Surface Selection tool. I adjusted the bump values at random, giving it a ".035" or ".050" negative bump, and a similar positive one - you are sort of raising and lowering the height of small groups of pixels, side by side... slight variations will make a plastic surface look and feel more like an eggshell and higher numbers/a greater range will make a surface look more like an orange peel or okra or a cucumber say.
This is a great thread; unfortunately I had to figure this out for myself several weeks ago... wish I'd had the thread then! Anyway happy Hallowe'en.
Thank you Roman_K2 the visual is most helpful Not quite sure how to load a texure or bump file that i make myself or where to put it but I will figure it out lol.
If you are using DAZ Studio, then select the surface and look for the bump strength parameter. Click the thumbnail image (or where it would be) and browse to your bump texture file. Set the bump strength probably to 100%, but then also set the "Negative Bump" and "Positive Bump" parameters to larger values so you can see the effect. (The default values are probably too small to see, in this screenshot they're not enough. Try larger values like maybe -1 and 1 until you can see what's happening, then lower it until it makes sense.)
You can also do something similar using the Displacement parameters instead of Bump, but it works a bit differently.
Awesome thank you! I have been going over the older issues of the ds creative as well but haven't run into this info yet so most helpful! (some really good info in there for any other newbies who want to learn all kinds of neat stuff. Not to mention all the freebies lol). Hoping to have a bit of time this weekend to explore this further
Here's a good article on the difference between bump, normals and displacement:
http://blog.digitaltutors.com/bump-normal-and-displacement-maps/
Great link, Cris.
Take away from that...
All three do similar things. Bump/normal maps is good for fine details/things that don't need to contribute to the surface profile/shadows.
Normals are bump maps on steroids.
Displacement moves actual geometry and is great for 'gross' details/major features.
Bump/normal maps give the illusion of detail, displacement provides actual detail (how fine is dependent on the number of polys/subdivision level).
Thank you for the link and thank you for explaining things in a way that is easy (ier) to understand!