When working with objects that are textured by realtime shaders, Softimage can automatically create tangents and binormals on-the-fly. This can give faster playback and interaction in Realtime Shader display modes (OpenGL and DirectX) than using the operator-based Tangent and Binormal properties, because by default the operator-based properties rebuild both themselves and their acceleration structures whenever deformations or topological modifications are applied. To use the automatic tangents and binormals, just don't specify a Tangent or Binormal property as the vertex attribute input in the realtime effects shader's property editor. For more information, see Setting Up Effects Shaders in the Render Tree and Creating User Interfaces for Vertex Shader Inputs [Realtime Shaders].
Leave these blank to automatically generate tangents and binormals.
Some notes about automatic tangents and binormals:
A texture projection is required. Automatic tangents and binormals are always based on the first texture projection defined on the object in creation order.
RenderMap and Ultimapper do not use automatic tangents and binormals. You should specify operator-based properties as appropriate.
Automatic tangents and binormals are not exported. You should apply operator-based properties before exporting if required.
