In Cinema 4D, materials consist of channels. Shaders can be assigned to these channels; shaders may consist of images, effects, or layers that contain additional shaders.

Each channel, and within them the shaders, are represented in GDL script by a compound parameter name. For example, if you wish to create a color shader in the color channel, and then assign a particular color to it, you can do the following:

dim color[3]
    color[1] = 0    ! red
    color[2] = 0    ! green
    color[3] = 1    ! blue

define material "c4d_mat" 2,    ! usual material parameters, matte (type = 2)
		1, 0, 0,        ! usual parameters, simply red					
    additional_data C4D_ChCol_State  = 1,       ! turn on the 	channel
                    C4D_ChCol_Texture = "1",    ! add a shader to the channel 
						!   - its params will end with _1
                    C4D_ShColor_Color_1 = color	! set shader parameter(s) 
                                                !   - now it is blue by the color array

Available channels

Each channel – except size and illumination – has a ‘State’ parameter, which represents the channel’s on/off status. The Color and Specular channels are turned on by default, the rest are off.