Can someone please point me to a tutorial on how to add bump maps. I don’t understand what they do.
Bump maps give the appearence of displacement though it doesn’t displace the object, most bumpmaps are black & white images which in blender you use as an image texture and click the nor. button in the shader properties
Create a simple sphere.
Hit F5 and go into Shading Mode.
Add a new texture (material menu-window thing). In the menu square labeled ‘Texture’ (has a vertical line of empy button-boxes) click ‘Add New’.
Click the newly created ‘Map Input’ tab. Click ‘Sphe’ (from the choices Flat, Cube, Tube, Sphe).
Click the ‘Map To’ tab, click ‘Nor’ (to the right of Col). Find the slider in the same menu area that says ‘Nor’ and probably 0.50- this determines how ‘bumpy’ the Normal channel will be so remember this slider.
Hit F6 to go to the ‘Texure Buttons’ menus.
Find the words ‘Texture Type’, the button under it probably says ‘None’.
Click on None and change it to a Cloud texture, leave everything at the default.
Hit F12. Not really noticable.
Hit F5 and under ‘Map to’ change the Nor slider to 8.0 or so.
Hit F12.
That’s a bump map.
Note that the bumps are fake- the actual edges of the sphere’s geometry aren’t affected at all.
%| hmmm… all actual procedurals can be used for bumpmapping, now, and not only stucci? It didn’t used to, in the past. For bump-mapped clouds texture, I use to use the t_clouds plugin from:
http://www-users.cs.umn.edu/~mein/blender/plugins/
As I won’t have access to Blender until this evening, could someone confirm this? I’d be very grateful…
To consider what bump-maps are good for … “how would you create a golf-ball?”
A golf-ball is, of course, a highly-deformed shape; full of lots of little dimples. But if you try to build the actual geometry of such a thing – you create an immensely complex set of polygons and “for what?” For the dimples in a friggin’ golf ball?
So what you do instead is to create the image, a flat picture, of this bumpy pattern and wrap it around a smooth sphere (a trivially simple geometry). Tell the renderer to use this information to make the light reflecting off the sphere look like it’s reflecting off a bumpy surface, using the image (the “bump map”) to tell it how to do so.
You’ll see a lot of places, in the CG world, where this “mapping” technique is used. For example, you can clothe a character by painting a picture of clothes and wrapping it around him. You can have bump-maps; shadow maps; even displacement-maps. What you are achieving is the effect of what would otherwise require complex geometry (and the laborious calculations to match!) without all that work.
It’s a weird world we work in… (right now at least) we build three-dimensional models to produce what is ultimately going to be a two-dimensional output. These mapping techniques work that fact to our mutual advantage: “if the arrangement of pixels on the final 2D image is the same, or almost the same, with this technique that is vastly easier for the computer to do, who’s to know?” You feel like David Copperfield sometimes; producing something that looks so real but is so false…
yup, all textures work with bumpmapping now… pretty good actually.
.andy
Can you used uvmaped textures?
You probably would, to get a golf-ball.
The word “texture,” in human parlance, is really a much more limited use of the word than the CG meaning. In the world of the computer, a texture can affect many variables: what a surface looks like; how it scatters light; bumpiness; the degree of transparency.
In the Map To… page of the texture buttons, I see a total of 13 variables that a texture can affect – in different amounts and in any combination.
How that texture gets there … now, basically it’s either a procedural-texture, computer generated like “Marble,” or it is mapped from an external image. In the case of golf, an image would be the logical choice. (Search for “golf ball” [all terms] on this site and you can see exactly how it’s done.)
You can also use a bump map to deform the mesh itself. This involves the DISPLACE SLIDER on the bottom of the MAP TO SETTINGS. You can use a bump map to make hight fields (terrain and yes the surface of a golf ball). As the deformation only moves in one direction no matter what primative your using it’s a bit more work for adding it to a sphere.
Recomends for this type of displacement.
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Many vertices as the displacement is moving the verticies present in the mesh it won’t add to them (perhaps it should in the future).
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The greyscale image is what is used. If you use a color image blender will convert the data to greyscale. This is both good and bad in that you need not create a greyscale image to map the bump but you may get unexpected results if you don’t. As it is based on the lightness or darkness of the image.
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Procedurals work reall good for this type but you can take an image convert it to greyscale and give a 2D image a 3D height field (psudo 3D model).
As for using Bumps in NOR mode. One thing to remember is that it’s an illusion not a physical deformation. If for instance you add a bump map to make the shutters on your modelled house look like they have depth the lessor the angle to the shutters from the camera the more you will notice it’s not 3D. It’s kinda like adding drop shadow in PSP or other 2D graphics software. You see the shadow but the closer you get to the plane of the object the less you see the shadow until it’s gone altogether.
So as long as your bump mapped surface doesn’t pertrude to far beyond the angle of incidence with the camera it will work quite well. The problem is that you are restricted to those angles with in that.
Ronson2k
In the Map To panel for the texture, choose UV - you’ll have to add the image as a usual texture as well as in face-select for this to work.