diff --git a/away3d/materials/compilation/ShaderRegisterData.hx b/away3d/materials/compilation/ShaderRegisterData.hx
index c7c6808e..3198c911 100644
--- a/away3d/materials/compilation/ShaderRegisterData.hx
+++ b/away3d/materials/compilation/ShaderRegisterData.hx
@@ -1,32 +1,130 @@
 package away3d.materials.compilation;
 
 /**
- * ShaderRegisterData contains the "named" registers, generated by the compiler and to be passed on to the methods.
+ * A number of commonly-available registers, generated by the compiler and made
+ * available to the methods.
  */
 class ShaderRegisterData
 {
+	/**
+	 * Varying. Contains `animatedNormal`, converted to world space. Not assumed
+	 * to be normalized.
+	 */
 	public var normalVarying:ShaderRegisterElement;
+	
+	/**
+	 * Single-pass only. Varying. Contains the tangent to the vertex, in local
+	 * space. To use this, set `needsTangents`.
+	 */
 	public var tangentVarying:ShaderRegisterElement;
+	
+	/**
+	 * Single-pass only. Varying. Contains a vector orthogonal to both
+	 * `animatedNormal` and `animatedTangent`, in world space.
+	 * 
+	 * To use this, set `methodSetup.normalMethod.normalMap`.
+	 */
 	public var bitangentVarying:ShaderRegisterElement;
+	
+	/**
+	 * Varying. Contains the UV coordinates, with any animations applied. To use
+	 * this, set `needsUV`.
+	 */
 	public var uvVarying:ShaderRegisterElement;
+	
+	/**
+	 * Varying. Contains the secondary UV coordinates, with any animations
+	 * applied. To use this, set `needsSecondaryUV`.
+	 */
 	public var secondaryUVVarying:ShaderRegisterElement;
+	
+	/**
+	 * Varying. Contains the direction the camera to the vertex. Not normalized.
+	 * To use this, set `needsView`.
+	 */
 	public var viewDirVarying:ShaderRegisterElement;
+	
+	/**
+	 * Fragment temp. Contains the final shaded color, to be written to
+	 * `fragmentOutputRegister`.
+	 */
 	public var shadedTarget:ShaderRegisterElement;
+	
+	/**
+	 * Vertex temp. Contains the vertex position in world space. To use this,
+	 * set either `needsGlobalVertexPos` or `needsGlobalFragmentPos`.
+	 * 
+	 * Multi-pass: may be freed before methods run; do not rely on it.
+	 */
 	public var globalPositionVertex:ShaderRegisterElement;
+	
+	/**
+	 * Varying. Contains the vertex position in world space. To use this, set
+	 * `needsGlobalFragmentPos`.
+	 */
 	public var globalPositionVarying:ShaderRegisterElement;
+	
+	/**
+	 * Vertex temp. Contains the vertex position in local space.
+	 */
 	public var localPosition:ShaderRegisterElement;
+	
+	/**
+	 * Vertex attribute. Contains the normal to the vertex, in local space. Not
+	 * assumed to be normalized.
+	 */
 	public var normalInput:ShaderRegisterElement;
+	
+	/**
+	 * Vertex attribute. Contains the tangent to the vertex, in local space. Not
+	 * assumed to be normalized.
+	 */
 	public var tangentInput:ShaderRegisterElement;
+	
+	/**
+	 * Vertex temp. Contains `normalInput.xyz`, normalized.
+	 * 
+	 * Single-pass: uses world space. Multi-pass: uses local space.
+	 */
 	public var animatedNormal:ShaderRegisterElement;
+	
+	/**
+	 * Vertex temp. Contains `tangentInput.xyz`, normalized.
+	 * 
+	 * Single-pass: uses world space. Multi-pass: uses local space.
+	 */
 	public var animatedTangent:ShaderRegisterElement;
+	
+	/**
+	 * Fragment constant. Contains (0.5, 0, 1/255, 1).
+	 */
 	public var commons:ShaderRegisterElement;
+	
+	/**
+	 * Varying. Contains the vertex position in screen space. To use this, set
+	 * `needsProjection`.
+	 */
 	public var projectionFragment:ShaderRegisterElement;
+	
+	/**
+	 * Fragment temp. Contains `normalVarying.xyz`, normalized.
+	 */
 	public var normalFragment:ShaderRegisterElement;
+	
+	/**
+	 * Fragment temp. Contains the direction from the camera to the fragment.
+	 * Normalized. To use this, set `needsView`.
+	 */
 	public var viewDirFragment:ShaderRegisterElement;
+	
+	/**
+	 * Multi-pass only. Vertex temp. Contains a vector orthogonal to both
+	 * `animatedNormal` and `animatedTangent`, in local space.
+	 */
 	public var bitangent:ShaderRegisterElement;
 	
 	public function new()
 	{
 	
 	}
-}
\ No newline at end of file
+}