PBR textures in Blender, Unity, Unreal and Godot: OpenGL vs DirectX normals, colour space, tiling

Colour space is the single most common mistake. Only the albedo (base colour) map holds colour meant for display, so only it should be read as sRGB. Every other map holds data, and must be read as linear, also called Non-Color or “sRGB off”.

If a material looks washed out or too shiny, a data map is probably being read as sRGB. If the colour looks too dark and saturated, the albedo is probably being read as linear.

Tangent-space normal maps store a direction in the red, green and blue channels. There are two conventions for the green channel: OpenGL style, where green points up (often written Y+), and DirectX style, where green points down (Y−). The maps look almost identical, but using the wrong one inverts the lighting on bumps.

How to spot the wrong convention

Look at a material with clear bumps, such as brick mortar or cobblestone joints, under a single light. If the grooves look raised and the bricks look sunken, or the highlights appear on the side facing away from the light, the green channel is inverted. Flip it in the engine’s import settings or invert the green channel in an image editor.

1. Add an Image Texture node for each map and connect them to a Principled BSDF.
2. Set the albedo node’s colour space to sRGB and every other map to Non-Color.
3. Route the normal map through a Normal Map node (tangent space) before the BSDF’s Normal input.
4. Connect roughness and metallic directly. Leave metallic at 0 for materials without a metallic map.
5. Optional: connect the height map to a Displacement node and the Material Output’s Displacement input. In Cycles, set the material’s displacement method to include true displacement, and subdivide the mesh enough to show it.

Ambient occlusion is usually left out in Cycles and Eevee, which calculate their own. For tiling, add a Texture Coordinate node and a Mapping node, and drive every map from the same Mapping node so they stay aligned.

• Select the normal map and set Texture Type to Normal map.
• For roughness, metallic, AO and height, untick sRGB (Color Texture) in the import settings.
• Unity’s Lit shaders use smoothness, the inverse of roughness. In URP and the Built-in pipeline, smoothness is read from the alpha channel of the metallic map (or the albedo), so pack a texture with metallic in red and inverted roughness in alpha.
• HDRP uses a Mask Map: metallic in red, ambient occlusion in green, a detail mask in blue and smoothness in alpha.
• Set tiling in the material’s Tiling fields; keep all maps on the same tiling.

• On the normal map texture, tick Flip Green Channel if the map is OpenGL style, and keep the compression setting at Normalmap.
• For data maps, untick sRGB. For packed maps, use the Masks compression setting.
• A common pattern is an ORM texture: occlusion in red, roughness in green and metallic in blue. One texture sample then feeds three material inputs, which saves samplers.
• For tiling, multiply a TexCoord node by a scalar or vector parameter and feed it to every Texture Sample in the material.

• Create a StandardMaterial3D and assign the albedo texture.
• Enable Normal Map and assign the normal texture. Godot expects OpenGL-style normals.
• Assign roughness and metallic textures and check which channel each reads from (the texture channel setting next to each slot).
• For packed occlusion/roughness/metallic textures, use ORMMaterial3D instead.
• Set tiling with UV1 Scale in the material, or turn on triplanar mapping for terrain-like surfaces without good UVs.

Seamless textures repeat without visible edges, but the repetition itself can still show. Getting the scale right is the first step. Texel density is the number of texture pixels per metre of surface. A 2048 px texture covering 2 m gives 1024 px/m; covering 4 m gives 512 px/m.

Keep density consistent across neighbouring surfaces so one wall doesn’t look sharper than the floor next to it. To hide repetition:

• break up large areas with trims, decals and props;
• blend two materials with a mask, or add a large-scale variation texture multiplied over the albedo;
• rotate or offset UVs on adjacent surfaces.

A height map can drive true displacement (moving vertices, which needs dense geometry or tessellation) or parallax occlusion mapping (a shader trick that fakes depth on flat geometry). Use 16-bit height maps where you can: 8-bit height has only 256 levels and produces visible stepping when displaced. Start with a small displacement strength and increase it until edges look right; real-world surfaces like brick need only a centimetre or two.

Our texture pack ships 16-bit height maps and OpenGL normals for every material, with metallic maps only for the two metals. For a starter set of matching game assets, browse Game Assets; the textures pair well with the low-poly dungeon kit. Remember that file names like brick_normal.png don’t tell you the convention; check the pack’s README.