The
calculation of the tangent space vectors in Mudbox is as follows:
- Calculating per vertex tangent and binormal
vectors for each face.
- For each vertex A in the face (assume
that the two adjacent vertices are B and C)
- A.tangent = (B.pos-A.pos) * (B.tc.u-A.tc.u)
+( C.pos-A.pos) * (C.tc.u-A.tc.u)
- A.binormal = (B.pos-A.pos) * (B.tc.v-A.tc.v)
+ (C.pos-A.pos) * (C.tc.v-A.tc.v)
- Smooth values for common vertices. Each
vertex will get a Tangent Normal Binormal index based on the selection
in the Index Source combo box in the following way:
- A. Position:
The position index of the vertex will be used. Those vertices with
a common 3D positions will use the same tangent space.
- B. TC: The
position index of the vertex will be used. Those vertices with a common
3D positions will use the same tangent space.
- C. Global:
Use a different index for all the vertices, so all vertices will
have separated tangent space.
NoteVertices with the
same index use the same vectors, so their tangent binormal and normal
vectors are added together and normalized.
- Orthogonalization based on the corresponding
options selected in the Texture Extraction window.
- Calculation of the cross products. If
you selected an option in the user interface for this, then the
previously calculated vector will be replaced by the cross product
of the other two vectors.
- Switch tangent with binormal if you select
the Switch Tangent With Binormal option.
- Invert vectors marked at the Flip part
of the user interface.