Sunday, 16 August 2009

Normal Maps

Normal mapping, and in fact all progress in 3D computer graphics, never ceases to amaze me... Using just 12 triangles you can achieve some truly amazing things; this is a shipping container initially modelled using about 10,000 triangles then simplified using normal mapping to a simple cuboid. Hopefully the guys over at the OpenTTD high resolution sprite project can find some use for it!

After modelling the container was textured with a variety of "layers" to give flexibility, in this case there is a base colour (which affects the whole model except the bare metal door locks/handles), a paint mess texture (to add some variation to the otherwise "flat" colour), an ambient light texture (to give quick approximate shading on the fine details), a dirt and rust texture (separate from the base colour so its influence can be adjusted separately) and a detail texture with logos, stickers, etc.

Even more detail was added using normal mapping from the rust and detail textures; this gives the slightly lumpy look to the rust and exaggerates the edges of the detail making the logos look as if they were actually stuck/painted on.

Watch a video (HD available) of it rotating here.

These are low quality versions of the textures used for diffuse and normal mapping, the originals are all 1024x1024px except the detail texture which is 2048x2048px to preserve the sharp edges of the shapes.

The bump map from which the normal map was calculated:
The ambient lighting/shadowing map:
The mask used to show where needs to take the base colour of the container:
The messy paint detail, complete with patchy repairs and dribbles, this was mapped to darken the base colour of the crate:
The rust image, this was mapped with the black areas as a dark rust grey and the white areas as transparent:
And finally the detail texture, this texture has an alpha channel so the underlying textures show through:
Software used:
Blender - 3D modelling, texturing and rendering
Paint.net - Texture design
Creature House Expression - Design of the detail texture
The GIMP - More texture design!
VLC - Video transcoding

http://www.cgtextures.com/ - Paint smudge and rust stock texture images

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