How to setup material blending for Source 2 models in Blender

A brief guide on configuring vertex-based material blending for Source 2 models using Blender and ModelDoc.

Counter-Strike 2

Step 1. Creating a Color Attribute

• In Blender, switch to Vertex Paint mode.
• Click the Attribute dropdown in the top header.
• Click the plus button on the right.
• Set the following parameters in the pop-up window:
  • Name: VertexPaintBlendParams
  • Domain: Face Corner
  • Data Type: Byte Color
• Click Add.

Step 2. Vertex Painting

In Blender, switch to Vertex Paint mode and paint your model according to the Counter-Strike 2 shader requirements below.

Csgo Environment Blend

Vertex Сolor	HEX	Layer in shader	Notes
Black	#000000	Layer 1
Red	#FF0000	Layer 2
Green	#00FF00	Layer 3
Blue	#0000FF	Wetness	Apply over the black color (Layer 1)
Pink	#FF00FF	Wetness	Apply over the red color (Layer 2)
Cyan	#00FFFF	Wetness	Apply over the green color (Layer 3)

Csgo Simple 2way Blend

Vertex Сolor	HEX	Layer in shader
Black	#000000	Layer 1
Red	#FF0000	Layer 2

Step 3. Result

Half-Life: Alyx

Step 1. Creating a Color Attribute

• In Blender, switch to Vertex Paint mode.
• Click the Attribute dropdown in the top header.
• Click the plus button on the right.
• Set the following parameters in the pop-up window:
  • Name: VertexPaintBlendParams
  • Domain: Face Corner
  • Data Type: Byte Color
  info

  Although the Half-Life: Alyx model compiler ignores custom attribute names, you can specify this specific name to ensure compatibility with other Source 2 games.

• Click Add.

Step 2. Vertex Painting

In Blender, switch to Vertex Paint mode and paint your model according to the Half-Life: Alyx shader requirements below.

Vr Simple 2way Blend

Vertex Сolor	HEX	Layer in shader
Black	#000000	Layer 1
Red	#FF0000	Layer 2

Step 3. Renaming a data stream

Since the Half-Life: Alyx model compiler ignores custom FBX attribute names, you must rename the data stream for correct blending.

• Open your model via ModelDoc.
• Right-click on the render mesh.
• Find and select Add RenameStream.
• Click on RenameStream under the desired mesh and fill in the nodes as shown below:
  • From Name: color$0
  • To Name: VertexPaintBlendParams$
  info

  The number corresponds to the color index order in Blender's color attributes list. By default, this is color$0. However, if your object stores other attributes, this data stream will shift down the list, which means you'll need to enter color$1 or a higher index to select the correct index.

Step 4. Result

Dota 2

Step 1. Creating a Color Attribute

• In Blender, switch to Vertex Paint mode.
• Click the Attribute dropdown in the top header.
• Click the plus button on the right.
• Set the following parameters in the pop-up window:
  • Name: VertexPaintBlendParams
  • Domain: Face Corner
  • Data Type: Byte Color
• Click Add.

Step 2. Vertex Painting

In Blender, switch to Vertex Paint mode and paint your model according to the Dota 2 shader requirements below.

Multiblend

Vertex Сolor	HEX	Layer in shader
Black	#000000	Layer 0
Red	#FF0000	Layer 1
Green	#00FF00	Layer 2
Blue	#0000FF	Layer 3

warning

For correct vertex blending behavior, make sure to check the "No Vertex Color" checkbox in the shader options.

Step 3. Result