How are normal vectors expressed in a normal map?
Normal vectors in a normal map are expressed in tangent space where normals always point roughly in the positive z direction. Tangent space is a space that’s local to the surface of a triangle: the normals are relative to the local reference frame of the individual triangles.
What is the name of the normal map node?
Name of the UV map to derive normal mapping tangents from. When chained with an Image Texture node, this UV map should be the same as the UV map used to map the texture. Normal that can be used as an input to BSDF nodes.
How is a mapping node similar to a UV map?
For this vector type, the node performs a straightforward transformation. Transforming a texture coordinates is analogous to transforming a UV map. For instance, translating the texture coordinates along the positive X axis would result in the evaluated texture to move in the negative X axis, much like if one translated a UV map.
How to solve the problem of normal mapping?
The normal map is defined in tangent space, so one way to solve the problem is to calculate a matrix to transform normals from tangent space to a different space such that they’re aligned with the surface’s normal direction: the normal vectors are then all pointing roughly in the positive y direction.
How is tangent space related to normal mapping?
Tangent space is a space that’s local to the surface of a triangle: the normals are relative to the local reference frame of the individual triangles. Think of it as the local space of the normal map’s vectors; they’re all defined pointing in the positive z direction regardless of the final transformed direction.
What’s the problem with transforming normals into vectors?
The problem with normals, is that we tend to assume that transforming them in the same way we transform points and vectors will work.
How does normal mapping work in RGB Texel?
In each RGB texel is encoded a XYZ vector : each colour component is between 0 and 1, and each vector component is between -1 and 1, so this simple mapping goes from the texel to the normal : The texture has a general blue tone because overall, the normal is towards the “outside of the surface”.