Sampler Info

These are the different sample options. Once you select what you would like to sample, click the + button () to add an output socket for it. You can then use the - button () to remove the input socket of the currently selected Sampler. You can have only one output per sampler.

Samplers – Determines the data to be sampled from the scene:

Point – Specifies the shading point in reference space.
Point Object – The X, Y, and Z coordinates of the point are converted to RGB data according to Object space. This outputs a Position Pass for use in compositing.
Point Camera – The X, Y, and Z coordinates of the point are converted to RGB data according to Camera space. This outputs a Position Pass for use in compositing.
Point Relative – X, Y, and Z coordinates in the object space of the Relative node are converted to RGB data. This outputs a Position Pass for use in compositing.
Point Reference – Specifies the shading point in reference space.
Geometric Normal – Specifies the geometric normal in world space.
Flipped Normal – Outputs the direction of the normal vector, but flipped.
Normal – The direction of the normal at the particular shaded point according to which the Coordinate system is set (Object, World, Camera, or Relative space).
Normal Object – The surface normal for the sampled point in object space.
Normal Camera – The X, Y, and Z coordinates of the normals are converted to RGB data according to Camera space.
Normal Relative – This specifies the scene node relative to which the normal data is stored.
Normal Reference – Specifies the bump normal in relative space.
Bump Normal – Specifies the bump normal in world space.
Bump Normal Object – The X, Y, and Z coordinates of the normals are converted to RGB data according to Object space.
Bump Normal Camera –  The X, Y, and Z coordinates of the normals are converted to RGB data according to Camera space.
Bump Normal Relative – X, Y, and Z coordinates in the object space of the Relative node are converted to RGB data.
Reflection – Commonly used for adjusting reflections in the composite.
Reflection Object – The X, Y, and Z coordinates of the reflections are converted to RGB data according to Object space.
Reflection Camera – The X, Y, and Z coordinates of the reflections are converted to RGB data according to Camera space.
Reflection Relative – X, Y, and Z coordinates in the object space of the Relative node are converted to RGB data.
Refraction – Commonly used for adjusting refractions in the composite.
Refraction Object – The X, Y, and Z coordinates of the refractions are converted to RGB data according to Object space.
Refraction Camera – The X, Y, and Z coordinates of the refractions are converted to RGB data according to Camera space.
Refraction Relative –  X, Y, and Z coordinates in the object space of the Relative node are converted to RGB data.
View direction – Specifies the view direction.
Frame Time – Specifies the current frame (image) time.
Ray Time – The ray time within the motion blur interval.
Frame Index Offset – Outputs an offset from the current frame for motion blur intervals longer than one frame. For example, if you have a Motion Blur interval spanning three frames, the output will return -1, 0, or 1, depending on the ray time.
Facing Ratio – Specifies the direction of the normal vector relative to the camera.
Ray Depth – Specifies the ray length.
Path Length – Specifies the path length. 
Transparency Level – Outputs how many transparency intersections have occurred at the point of intersecting the first surface along the ray path.
Pixel Center – Specifies the current sample image coordinates.
Camera near Clip Plane – Controls the camera near the clipping plane, calculated from the scene bounding box, and the camera transform in scene units.
Camera Far Clip Plane – Controls the camera far clipping plane, calculated from the scene bounding box, and the camera transform in scene units.
Uv Coord – Specifies the UVW coordinates of the point being shaded.
Uv Coord Clamp – Specifies the clamped UVW coordinates of the point being shaded.
Uv Coord Tile – Specifies the tiled UVW coordinates of the point being shaded.
Tangent U Camera – Controls the U axis of the currently shaded point's UVW space, transformed in camera space.
Tangent V Camera – Controls the V axis of the currently shaded point's UVW space, transformed in camera space.
Tangent U Object – Controls the U axis of the currently shaded point's UVW space, transformed in object space.
Tangent V Object – Controls the V axis of the currently shaded point's UVW space, transformed in object space.
Tangent U World – Controls the U axis of the currently shaded point's UVW space, transformed in world space.
Tangent V World – Controls the V axis of the currently shaded point's UVW space, transformed in world space.
Random by Render ID – Assigns a random color/texture by each object's render ID.
Random by Poly Shell – Assigns a random color/texture based on the polygon shell the current face belongs to. 
Random by Scene Name – Assigns a random color/texture by each object's full scene path.
Random by Instance ID – Assigns a random color/texture by each instance ID.
Material ID – The material ID for the sampled point.
Object ID – Returns the object ID for the object at the sampled point.
Parent Object ID – Returns the object ID for the parent object of the sampled point.
Instance ID – Returns the instance ID of the object at the sampled point.
Velocity – Specifies the velocity at the intersection point in scene units per frame (in world space).
Speed – Specifies the speed at the intersection point in scene units per frame. 
Face Index – Correlates points between separate bakings of the same mesh.
Barycentric Coordinates – Displays the Barycentric coordinates of the rendered objects.

Transform – Allows a Transform or Matrix node to be connected to determine the sample's transformation(s).

UV Set Name – The default UVW mapping channel used when the Samplers is set to UV Coord. Specifies the UVW Channel to render by the name of the UV set. 

Refraction Ior – Sets the index of refraction when Refraction is set as the Output.