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General Utilities
Set Range
Sampler Info
Provides you with information about each
point on a surface as it is being sampled, or calculated, for rendering
purposes. Sampler Info can give you information
about a point’s position in space, its orientation and tangency, and
its location relative to the camera.
Many of the attributes for this node provide values
in camera coordinate space, the local
object space of the camera. Each camera (in its own space) is located at
the point 0, 0, 0. It looks straight along the negative Z axis,
and the positive Y axis points up.
Find this utility in the Create
Bar (see
Hide, resize or customize the Create bar).
To use this utility, see
Use the Sampler Info utility.
- Point World
-
Provides
the position currently being sampled relative to the X-,Y-, and
Z-axis of the world.
- Point Obj
-
Provides
the position currently being sampled relative to the X-,Y-, and
Z-axis of the object.
- Point Camera
-
Provides
the point of the object being shaded. This point is located in XYZ
camera space. You can connect this surface point in materials for the
object being shaded to show some interesting effects based on the
camera view.
- Normal Camera
-
Provides
the orientation of a face relative to the camera.
- Uv Coord
-
Provides
the UV coordinates of a point to be shaded. The convention is that
UV coordinates are measured from 0 0 to 1 1.
- Ray Direction
-
Indicates
the direction in which the current point is seen from the camera.
Use this attribute in materials for objects to provide the direction towards
the camera for every pixel in the object.
- Tangent UCamera, Tangent
VCamera
-
Sets
the surface tangents in camera space (as opposed to world space
or object space). For polygons, the tangents are generally not defined.
NURBS have a well-defined tangent space (as visible in Maya; create
a NURBS object, display its CVs and notice the NURBS object has a
U direction and a V direction).
Mathematically, tangents provide an instantaneous
direction perpendicular to their point of origin on a surface. Their
magnitude is affected by the rate of change (curvature) of the surface.
A good math book should have a diagram showing the tangent to a
curve, which can then be extrapolated to give you an idea of what
tangents on a surface look like. Tangent UCamera and Tangent
VCamera attributes are for advanced users only.
- Pixel Center
-
Provides Pixel Center X
and Pixel Center Y. The result
depends on the image, not on the geometry.
- Facing Ratio
-
Produces
a value that varies between 0 and 1 depending on the angle between
the surface normal and view direction.
- Flipped Normal
-
Turn
on or off depending on whether the object is textured differently
on either side. The flipped normal attribute indicates if the surface
normal is flipped which also tells you which side of the surface
Maya is shading.