How To: Channel Packing In Substance Designer

In a previous article I went over how channel packing works in Substance Painter. In this article I will explain how to pack channels in another Substance tool: Substance Designer.

A quick refresher, what is channel packing?

Channel packing, also revert to as “packed channels” is a way to optimize textures in your game engine. Digital images consist of 3 or 4 channels (depends if you use the alpha channel). These channels are Red Green Blue and Alpha. Or in short: RGBA

Every channel can hold a black and white image and together they form the whole image. In 3D rendering a lot of textures are black and white. Think about the metal, roughness, ambient occlusion and mask textures. These black and white textures can be stored in each of these channels. For instance:

  • R = Metal
  • G = Roughness
  • B = Ambient Occlusion
  • A = Mask

This way you now have one texture instead of 4 different textures.

How to do it in Substance Designer

Channel packing in Substance Designer is more straight forward than in Substance Painter.

There are four nodes that relate to channel packing in Substance Designer; RGBA Merge, RGBA Split, Alpha Merge and Alpha Split.

All the nodes related to channel packing in Substance Designer.

These nodes are pretty self explanatory but how do you get them in engine? I usually double click on on of these nodes and click “Save Image…”

That’s it! This is the easiest way to channel pack in Substance Designer. But there is more:

There is also a more elegant way of exporting them via an “output node”. Just create an Output node and name it after the naming convention of your channel packed textures. In my case that is “Mask”. In “INTEGRATION ATTRIBUTES” click “Add Item” and set the correct values.

In most cases just leave it as RGBA because even when your exported texture is only RGB it will not export RGBA. So there is no point in this case to set it to RGB. Set usage to “mask” and you’re done!

Example of channel packing various noises in one texture.

Using the Output node you can now also publish the .sbsar file and use this in Unreal Egnine or Unity. I never use .sbsar files in engine so I just stick to the save image method!

Also, I launched a Newsletter, I will be sending out tips and tricks about environment art.

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