The key to understanding 3D images lies in understanding the grey scale bump masks. These grey-scale images represent height, in 256 levels. (256 levels of grey, get it?) The grey image on the left represents a flat pyramid shape, with angled edges. Suppose we want it to be round?

There are two versions of the "paint-splatter" image above. The mask that created the one on the left was cereated by selecting the round, white area, and giving it a single gaussian blur of 16 pixels. The one on the right was created using multiple gaussian blurs, first 8 pixels, then 4, and then 2. After this process, I always *DE* select the area, and give it a final gaussian blur of one pixel, to knock off the harsh transition with the black background. Note the first image, the single large blur creates a rounded cone, while the multiple blurs create a more rounded shape. This is the process you will use time and time again. The images were raised by a height of "100", the maximum possible. You'll notice they appear bumpy. This is due to the extreme amount we've distorted the image, remember, that grey mask only has 256 levels. What I've done with the pieces below is this... First, select the rounded shape, (command+option+T). Choose "select/inverse" to select everything else but the shape. Fill it with black. Invert the selection again, and give it a blur of 1-2 pixels. This smooths the surface, and allows a little black to leak in and define the edges. Invert the selection again, and delete all that black, and you'll have the images below. You can check out the dialogue box I used in the "Lighting Effects" filter here.

The gradient tool will always create a sharp angled mask. Note the image on the top, in black & white, the shading simulates a curve nicely, but translated as height you see the sharpness of it. The next image shows how the radial offset can "chop off" the top of the cone. This is the same thing we first discussed in the last lesson with the "button" mask. Check the image below, here I applied a 4 pixel blur after the gradient tool. This gives me that "lava" look, an interesting effect I once used on my "rustdex" pages.

Virtually anything can turn into a believable texture. The image below was created by applying a "Cloud" filter on the mask, and then darkening the edges.

The last method I'll discuss here is using one of the 3 color channels as your bump mask. Here I've taken the "blue" layer, and raised the wheat background from this page with it. These can look cool at first, but tend to all have that same "beaten into copper" look. I like to place an image like this over an unmodified version, and decrease the opacity of the textured layer. This can give you some interesting highlights.