Shader Type: Texture (tool)
Output: Color
The XSI Model Map shader generates surface tangency data for a polygon mesh, using a given texture projection. The tangent points in the principal U direction of the texture projection and the binormal in the principal V direction of the projection.
The shader can return either the surface normal at intersection, surface tangent or binormal. All of these vectors are orthogonal unit vectors and together compose a coordinate reference frame at the surface intersection called “tangent space”.
The shader returns the vectors as encoded color information for ease in map generation. The red, green and blue channels encode the x, y and z vector components respectively. Each component value is range shifted from [-1,1] to [0,1].
In addition the shader can take as an input a previously generated normal map from, for example, a higher resolution object and transform that to the tangent space of the object this shader is applied to.
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Mapping Type |
Specifies the shader’s output. Choose one of the following options: Normals returns the surface normal at intersection. Normals in tangent space uses either the object’s surface normal or the input from a shader connected to the NormalMap input. Tangents returns the surface tangent at intersection. If no Texture Space is defined then the results are undefined. Binormals returns the surface binormal at intersection. If no Texture Space is defined then the results are undefined. |
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Texture Space |
Selects the texture projection to use for generating the tangency data. Object Selection: When multiple objects are selected, defines whether changes are applied to all objects or a specific one. This control updates automatically as you select objects in the scene, as long as the property editor is not locked. Property Selection: Lets you choose a Texture Support. If no texture support has been defined, you can create one by clicking New. If a texture projection is already defined, you can edit it by clicking Edit. Edit: Opens the Texture Support property page for the defined texture projection. New: Defines the new texture projection to be created. You can choose from the following: • UV: Projects the texture along the U and V. • Planar XY: Projects the texture on X and Y coordinates only. • Planar XZ: Projects the texture on X and Z coordinates only. • Planar YZ: Projects the texture on Y and Z coordinates only. • Cylindrical: Projects the texture as though it is a cylinder wrapped around an object. • Spherical: Surrounds the object with a spherical mapping across the whole surface with some distortion. • Spatial: The texture is centered on the scene’s origin. • Cubic: Applies the texture onto the object by first assigning the object’s polygons to faces of a cube, and then projecting the texture onto each face by default. The layout of a cubic projection can be completely customized using the options in the Texture Support property editor. • Camera Projection: The texture is mapped relative to the camera’s center. In this coordinate system, the camera is the center of the “world,” with an up vector, looking toward the negative Z axis. The result resembles an image projected from a camera. The texture will move with the camera and will be affected by any scaling, rotation, and translation. • Unique Uvs (Polymesh): Applies a texture to polygon objects by assigning each polygon’s UV coordinates to its own distinct piece of the texture so that no two polygons’ coordinates overlap each other. • Advanced: Opens the Create Texture Support property page from which you can explicitly define a texture projection. |
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