Flip Green

Normal maps come in two versions that differ only in the green channel. DirectX maps point green down and OpenGL maps point green up. Unreal and 3ds Max want DirectX. Unity, Blender, Godot and glTF want OpenGL.

Load the wrong one and the lighting flips vertically. Bumps look like dents, rivets look punched into the surface, and it looks fine from one side and wrong from the other. Flipping green swaps one for the other. Nothing else in the file changes, and running it twice gives you back the original.

How do I tell which one I have?

Find something with lighting you can predict, like a raised bolt or a scratch. If the light looks like it is coming from the wrong side vertically, the green channel needs flipping. Material Preview makes this easy to check.

Which engine wants which?

DirectX, green down: Unreal, 3ds Max, CryEngine. OpenGL, green up: Unity, Blender, Godot, Maya, and glTF assets.

Does flipping lose quality?

No. It is an exact swap of one channel, fully reversible, with no filtering or re-compression anywhere.

All tools

Edge Padding: Bleed UV island colors outward into empty space so textures stop showing dark seams at lower mip levels. Runs in your browser.

ORM Packer: Combine ambient occlusion, roughness and metallic maps into a single packed RGBA texture, with control over which map goes in which channel.

Tiling Checker: Preview a texture tiled 3x3 with the seams highlighted, plus a half-offset view, so visible edges and obvious repetition show up before the asset ships.

Material Preview: Preview albedo, normal and ORM maps together on a lit sphere or cube, without exporting into Unreal or Unity to check how a material looks.

Height to Normal: Convert a height, bump or displacement map into a tangent space normal map, with adjustable strength and a choice of DirectX or OpenGL output.

Combine Normals: Layer a detail normal map over a base one and keep the detail from both, instead of averaging them into something flatter than either.

Normal Strength: Scale how much a normal map bends the light, without rebaking it. Keeps the map valid instead of breaking it the way a contrast slider would.

Levels: Set the black point, white point, midtones and inversion of a roughness, AO, height or mask texture, with a live preview.

Rough ↔ Gloss: Convert a roughness map to glossiness or smoothness and back, for assets moving between engines that expect one or the other.

Renormalize: Restore a normal map after resizing, blurring or compression has weakened it, without changing which way any of it points.

Material from Photo: Generate albedo, height, normal, roughness and AO maps from a single photo, as a starting point you then tune.

Seamless Maker: Turn a photo or texture into one that repeats cleanly, by shifting it by half and blending the mismatched edges away.

AO & Curvature: Get ambient occlusion, curvature and cavity maps out of a normal map, with no high-poly mesh and no baker, for edge wear and dirt masks.

Channel Split: Split a packed ORM, RMA or mask texture back into one grayscale map per channel, exported individually or as a zip.