Cinema 4D Prime Material Manager Shaders Channel Shaders ChanLum Shader
Function available in CINEMA 4D Prime, Visualize, Broadcast, Studio & BodyPaint 3D
ChanLum

Basic Shader

Shader Properties

Samples [1..2147483647]

Use this setting to define the amount of samples ChanLum should take in a given area, be it along a normal or within a spherical sample area. The first sample is always taken from the offset sample point. If you set ChanLum to take just one sample, the settings that will no longer apply (like sample radius and type) will be grayed out.

Inital Offset [-∞..+∞m]

Use this setting to define the distance between the original surface point to be sampled ((P) in above illustrations) and the first sample point. This first sample point is a point in space along the surface normal.

Sample Radius [-∞..+∞m]

Use this setting to define the size of the area sample, in the illustrations above labeled (R). A larger radius generally means that you need more samples to get a smooth (read: low-noise) appearance.

Sample Type

Use this setting to select the sample type. It can be set to either Along Normal or to Area. If set to Along Normal, samples will be taken along the surface normal. This can be either a set of regularly spaced samples (if stochastic is turned off) or random samples anywhere along the normal, resulting in a more noisy appearance. If Sample Type is set to Area, ChanLum will need to take random samples within the area, so the stochastic option will be grayed out.

Stochastic

If this setting is turned on, ChanLum will take randomly-placed samples for you. If it is turned off (only possible if Along Normal was selected), it will take samples at regular intervals, leading to a smoother result with fewer samples.

Gaussian

This is an extra option when in Stochastic mode. If it is turned off, the random samples can be anywhere in the defined area. If it is turned on, the chance of getting samples closer to the offset first sample point is much greater than getting samples further away. This will generally lead to a more pleasant appearance. If you turn Gaussian off, you may want to decrease the sample area in order to get about the same effect as if it were turned on.

Shadows

Turn this setting off to omit shadows from the calculation. It is not advisable to do this in the instances described above, because they rely on shadows for the entire appearance. But there may be some instances where you may want to use ChanLum’s fog sample method without requiring shadows to be taken into account (such as with particle sprites), that’s what this setting was designed to do.

Seed [-2147483648..2147483647]

Use this setting to define the initial amount of random variation for Stochastic interpolation.

Use Lights
Lights

Use this setting to define which light sources should be included or excluded for ChamLum calculations. This setting applies to ChamLum only. Normal lighting and shadow casting will not be affected by this setting!

Light sources can be dragged and dropped from the Attribute Manager into the Lights field.