Conceal Layer option (from version 2023.1.2 - 10.14 and 2024.1 Alpha3 - 15.04 )
A special option 'Conceal Layer' has been added to all Octane materials using a Material Layer.
The main purpose is to provide a work around to a display issue in 3dsMax viewport, when using Ornatrix hair objects.
Ornatrix display the hair using the assigned material, while also displaying selection areas, custom elements (rgb painted channels, etc) and can blend those elements with the Overlay Opacity parameter.
When the assigned material uses multi materials, this display is incorrect.
Most Octane materials have a Material Layer slot, that is a sub material.
The new option 'Conceal Layer' will hide this sub material from 3dsMax requests and make the material behave like a material with no sub materials.
This fixes the Ornatrix display issue, and still allows to use Material layers.
The drawback is that will hide the Material Layer from the Slate material editor.
Also, with the Compact material editor, the Material Layer is still accessible, but when opening an existing layer, the parent material name will be incorrect.
So it is preferable to disable 'Conceal Layer' when editing materials.
Sample:
-Load ornax_Octane_mtl_mx20.max
-Note that the hair are displayed in the 3dsMax viewport using the 'color_squares_mtl' Octane Diffuse material
-Select the 'Fur Ball' node
-Select the Ox Edit Guides modifier
-Set Guide Channels / Current Channel to 'Vertex(0): colR'
-Note that the painted hair colors are now displayed in the 3dsMax Viewport (blended with 'color_squares_mtl').
-Adjust the 'Overlay Opacity' to see more or less of 'color_squares_mtl' and custom elements (painted hair colors)
-Disable / Enable the Conceal Layer option of 'color_squares_mtl'.
Note that when Conceal is enabled, the display shows both the hair custom elements and the octane material colors (but with a different mapping as when rendered with Octane),
and when disabled, the display shows only the octane material colors, correctly, as it will be renderer with Octane.
Reference:
This sample, ornax_arnold_blendMtl_Bug_mx20.max, not using Octane Render or materials illustrate that the issue do not comes from Octane:
Reproductioni steps:
-Load ornax_arnold_blendMtl_Bug_mx20.max
-Note that the hairs are displayed in the viewport using the blue and yellow 'wave_mtl'
-Select the 'Fur Ball' node
-Select the Ox Edit Guides modifier
-Set Guide Channels / Current Channel to 'Vertex(0): colR'
-Note that the painted hair colors are now displayed in the 3dsMax Viewport (blended with 'wave_mtl').
-Open the Compact material editor
-Note that the currently assigned material ('wave_mtl') is a simple 'Physical Material'
-Assign the second material ('blend_mtl') to the Fur ball
-Note that the viewport do not show the hair vertex colors anymore.
Reason:
The 'blend_mtl' has sub materials. (and note that 'wave_mtl' don't have sub material)
When a material containing sub materials is applied to the hair object, the resulting viewport display doesn't seems to use the 'Overlay Opacity' anymore.
(it behaves like 'wave_mtl' with 'Overlay Opacity' set to 0)