OpenGL or DirectX for Normal maps?

Hello! I’m creating my first prop pack for the Marketplace and was wondering what should my Normal map format be?

I haven’t found any official information, but I see that people mainly use DirectX. I’m creating a prop pack from photogrammetry, and Digital Asset Processing article says that normals should be OpenGL.

How to Set Up Substance Painter Properly - Digital Asset Processing (epicgames.com)

What’s the correct answer here?

Hi,

The only difference between OpenGL and DirectX is that the green channel is flipped.

If you’re building a Marketplace asset, I’d recommend using DirectX as it’s the default in Unreal. User’s won’t have to think about it. If they’re exporting to a ddc that is defaulting to OpenGL, they’ll have to flip it in the ddc.

Quixel Megascans, for instance, are using DirectX.

Hope that helps.