Friday, 7 March 2008

Normal Mapping

Just a quickie tonight, I just had to tell you about this great tutorial I found for creating normal maps. A genius called Ryan Clarke is altruistic enough to share his technique free and for nothing on his site here >.

Why do I care? Basically as an interactive media blokey, I am interested in this latest method of adding detail and realism to games.

To begin with 3D games were made using very low res meshes and texture mapping. Bump mapping adds more realism by adding a little height and depth to a surface texture on the polygons - this is done using a grayscale image to represent the height of the bumps, (the lighter the pixel the higher the altitude etc.) but it still looks like blocks with textures. To remove the blockiness of the models you would expect to have to increase the number of polygons they are made up of. This is no good for games where the computer has to render 30+ fps on the fly. This is where normal maps help.

To really grasp this you need to know what a normal is >.

Normal mapping works on a similar principle to bump mapping in that it is essentially a graphic wrapped round a mesh, but it goes much further. Normal maps use an RGB image which instead of containing just height data in each pixel contains the X Y Z 3D orientation of the normal.

These then render much more realistically almost as though they were meshes themselves and have the added bonus of rendering faster. This allows PC's and games consoles to increase the apparent level of detail in the models without increasing the polygon count.

Normal mapping (above) compared to bump mapping (below) - images courtesy of Inagoni makers of a normal mapping plugin for Carrara.
Anyway, I just wanted to bring your attention to the fact that you can make your own normal maps quite easily using a torch, a digital camera, and some image editing software - take a peep >

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