1. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling Texture mapping - how and why? lTexture mapping (including surface normal effects) is widely used to add realism to 3D graphics. lTexture can be defined using 2D or 3D maps, each with their advantages and disadvantages. lTexture mapping usually requires special anti- aliasing treatment. lSurface normal effects may be algorithmically generated.

2. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling What is texture? lTexture in 3D modelling has a broader meaning than in real life. lTexture is “surface complexity”. lTexture may be bumpiness or roughness of a surface, lbut may be changes in the colour of a surface, lso a tiled picture on a surface is also a texture. lTexture is surface and colour modulation.

3. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling 2D Textures l2D textures are "wallpapered" onto a surface, a complex and time-consuming operation. lThe 2D to 3D translation is extremely difficult to do well - shapes may be very complex. lIn POV, simple 2D textures are “projected” onto surfaces (effectively converting them to 3D textures).

4. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling 2D Textures l2D textures are very easy to generate and easy for humans to manipulate and visualise. lPOV has facilities for applying 2D textures to a limited range of shapes; lPlane lSphere lCylinder lTorus

5. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling 3D (Solid) Textures l3D textures are quicker for the computer to apply to an object since the object mapping is trivial. l3D texture to 3D object transformation is relatively simple. l3D textures may be algorithmically defined or come from some precursor 3D model.

6. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling 3D (Solid) Textures lComplex shapes look more effective with a 3D texture, since hollows and grooves will follow a coherent model. lFor example, a wood grain effect should be a 3D texture rather than a 2D texture, since wood is inherently a 3D material. lPOV has a range of predefined 3D textures that may be modified in many ways.

7. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling Aliasing Example

8. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling Text Aliasing Example

9. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling Aliasing Effects lTextures usually repeat across a surface and are particularly prone to noticeable aliasing. lScaling is obviously important, but any large scene is likely to contain objects at "just the wrong distance". lSurface texture may be dominated by, or badly distorted by, aliasing effects.

10. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling Surface Normal Examples Bumps,Dents,Wrinkles

11. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling Surface Normal Effects lIn POV, surface normal effects are a classical 2D texture since they "wallpaper", but they are algorithmic. lFlat surfaces have parallel normals. lCurved surfaces have angled normals.

12. Nic Shulver, N.A.Shulver@staffs.ac.uk Texture in 3D Modelling Surface Normal Effects lLight rays highlight the changes in the reflective properties of the modified surface. Perturbed Normals