--- Vertex color and float attributes ---
By default, a mesh will have the map channels set to be used with Octane attributes as follow:

Default channel settings:
3dsMax channel / Octane attribute
0 : vertex color 0
1 : UVW map 0
2 : UVW map 1
3 : UVW map 2
4 : vertex color 1
5,6,7,8 : float attribute 0,1,2,3

To set the channel usage differently, you need to add an Octane Geometry Properties modifier.



--- sample 1 - VertexColorOnImage.max
-Using default channel setting : 
 - channel 1 for UV map of the image
 - channel 0 for vertex color (vertex paint modifier)

--- sample 2 - VertexColors_doubleChannels_default.max -
-Using Default channel settings
-One single mesh with 2 Vertex Paint modifiers, set to channel 0 and 4 respectively
-3 instances of this , with 3 materials:
 - material 1 use a Colour vertex attribute with name set as 'MapChannel:0' 
 - material 2 use a Colour vertex attribute with name set as 'MapChannel:4' 
 - material 4 is a mix of material 1 and 2, and so is using both vertex color channels

--- sample 3 - VertexColors_doubleChannels_modifier.max ----
To use different channel settings, an Octane Geometry Properties modifier has been added:
-On the top of the 2 vertex pain modifier, an Octane Geometry Properties modifier is used to assign:
 - Octane Color 1 to 'channel 0' (vertex color)
 - Octane Color 2 to 'channel 1'
The second 'Color vertex attribute' texture has the name set as 'MapChannel:1' 

--- sample 4 - VertexAlphaOnImage.max ---
-Vertex paint set to channel -2 (Vertex Alpha)
-Octane Geometry Properties modifier : 'Vertex float 1' set to channel 'Alpha (-2)' 
-The plane material use an Opacity texture : Greyscale vertex attribute, with name set as 'MapChannel:-2'
-Changing the Componant for this 'Vertex float 1' (0,1,2) will use the correpondig color (r,g,b) from the Vertex paint channel.


Note that objects MUST be set as movable proxy to use vertex color.
