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[TUTORIAL] Channel Packing and setting up in Unreal Engine

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alexcz93 polycounter lvl 3

What's going on, fellow devs.

I recently uploaded a kind of informative video about what channel packing is and why it is important.

Additionally, I will show you how to pack your textures in Photoshop and finally, we are going to set it up correctly in Unreal Engine.

Channel packing sounds familiar to experienced users, but the goal of the video is to help beginners to understand this technique 😊

Hope you found this helpful.


Video: https://youtu.be/ku6iiyAIgfI


  • Obscura
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    Obscura grand marshal polycounter
    Spread the word, this is really useful stuff, and all artists should do it because we are still kinda bound on video memory. So its nice to talk about this. I have one note on your video. In your examples, you show that roughness is packed to the red channel. This is a bad idea, because using the default, and masks compression, the red channel has the worst precision (5bits if I recall correctly), while green and blue has full precision. And since metallic maps tends to have mostly full white and full black values, it doesn't need good precision, so it should always go into the red channel.
  • alexcz93
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    alexcz93 polycounter lvl 3
    Hi Obscura. Thanks for your feedback. Yes, you are right. In fact, I just pointed out that the user can switch positions if it's needed. Also, I didn't want to extend the video, because I wanted to make this as simple as that, but thanks again :) 
  • leleuxart
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    leleuxart polycounter lvl 9
    Pretty sure the Masks option is just DXT1, which is 5, 6, 5 for R, G, B. In my own tests, the one extra bit isn't really that noticeable across a wide variety of roughness textures. I would say emphasize the importance of picking one format, both RMA or MRA, and Masks vs Default(since they're identical, excluding the automatic Linear checkbox) and sticking with it, because switching between the two can be a pain in the ass and incurs wasted shader instructions/permutations.
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