PBR Map Export Cheat Sheet: Blender, Unity 6, and Unreal Engine 5

A PBR material is not a diplomatic passport. The same five image files can cross from Blender into Unity or Unreal and immediately acquire plastic shine, inverted dents, gray color, or the subtle charm of wet cardboard.

The pixels usually survived. The interpretation did not. This guide is a practical handoff sheet for metallic-roughness materials: what each map means, whether it is color or data, which values need inversion, and how to wire it in Blender, Unity 6 URP, and Unreal Engine 5.

The portable PBR set

Use unambiguous names and keep a lossless master:

• brick_basecolor.png
• brick_normal_opengl.png or brick_normal_directx.png
• brick_roughness.png
• brick_metallic.png
• brick_ao.png
• brick_height_16bit.png when displacement or parallax is part of the shader

Do not name a grayscale file gloss when it is actually roughness. Do not name a packed texture mask.png and hope Future You remembers the channels. brick_orm_R-AO_G-Rough_B-Metal.png is not glamorous, but it can prevent an afternoon of shader archaeology.

The rule that prevents most export mistakes

Color textures describe visible color. Data textures store numbers.

• Usually sRGB/color: base color and color emissive.
• Usually linear/non-color: normal, roughness, smoothness, metallic, ambient occlusion, opacity masks, and height.

sRGB decoding is desirable for an image representing perceived color. Apply it to a roughness value and the renderer changes the number before using it. A mid-gray roughness no longer means what the artist authored. The result often looks mysteriously too shiny or too dull.

Roughness and smoothness are opposites

In a roughness workflow, black is smooth and mirror-like; white is rough and matte. Unreal’s physically based material guide describes the Roughness input this way and recommends treating most pure materials as metallic 0 or 1.

Unity’s common URP Lit workflow exposes Smoothness. Its direction is reversed:

smoothness = 1 - roughness

If you pack roughness directly into a smoothness channel, dry concrete becomes polished stone. Invert it once during export or once in the shader—never both.

Normal maps: label the Y convention

Tangent-space normal maps differ mainly in their green/Y direction. Call the source OpenGL (+Y) or DirectX (-Y), and make the conversion deliberate. The red and blue channels remain unchanged; conversion flips green.

Also keep the normal texture linear. The Blender manual specifically instructs artists to set the Image Texture to Non-Color and to use the same UV map for the image and tangent calculation.

There is no substitute for a light test. Put a recognizable diagonal scratch on a sphere or beveled cube and move one hard light around it. If the scratch caves inward, flip Y. If only UV seams break, investigate tangents, triangulation, and mirrored islands instead.

Blender setup: keep the graph literal

For a Principled BSDF material:

1. Load base color as sRGB/Color and connect Color → Base Color.
2. Load roughness as Non-Color and connect Color → Roughness.
3. Load metallic as Non-Color and connect Color → Metallic.
4. Load the normal map as Non-Color, pass it through a Normal Map node set to Tangent Space, then connect Normal → Normal.
5. Use height through a Bump node for a cheap preview or a displacement workflow when the render setup and mesh subdivision support real displacement.

Ambient occlusion has no universal “plug this here and physics is solved” role in the Principled BSDF. For game export, preserve AO separately or in your agreed packed map. Avoid permanently multiplying strong AO into base color; baked darkness can fight the destination engine’s lighting and screen-space AO.

Unity 6 URP setup: pack for the shader you use

A standard URP Lit material accepts a Base Map and Normal Map, then uses metallic/smoothness and occlusion controls. For Unity’s documented Lit and Complex Lit channel-packed workflow, build one RGBA texture like this:

• R: metallic
• G: ambient occlusion
• B: unused
• A: smoothness

The official Unity 6 URP channel-packed texture guide also says to disable sRGB (Color Texture), then assign the same packed image to the Metallic and Occlusion properties. Remember that alpha stores smoothness, so invert an authored roughness map before packing it there.

Unity supports custom Shader Graph layouts too. If your team uses RMA, ORM, or a bespoke terrain shader, that graph—not this generic layout—is the contract. Put the convention in the filename and importer preset.

Unreal Engine 5 setup: direct sockets, optional masks

Unreal’s default material node makes the basic wiring pleasantly direct:

• Base color texture → Base Color with sRGB enabled.
• Normal texture → Normal; verify normal-map compression and sRGB disabled.
• Roughness texture → Roughness with sRGB disabled.
• Metallic texture → Metallic with sRGB disabled.
• AO texture → Ambient Occlusion with sRGB disabled.

For runtime efficiency, pack grayscale masks. A common ORM convention is R = AO, G = roughness, B = metallic. Unreal does not magically require that order; it lets a material read whichever channel you connect. Epic’s texture mask documentation explains the general technique of storing different masks in RGB or RGBA channels. Choose one studio convention and automate it.

ORM is also convenient around glTF because the glTF 2.0 specification reads roughness from G and metalness from B; its occlusion texture reads R and may reference the same image. That compatibility is useful, but your Unreal master material still needs the channels wired explicitly.

Channel packing: savings with paperwork

Packing three grayscale maps into RGB can reduce texture samples and file count. It can also make artifacts harder to isolate, couple maps that might want different resolutions, and produce waste if a fourth alpha channel forces a more expensive compression format.

Keep separate, lossless masters. Pack only at the engine-export stage. Record:

• the channel order;
• whether roughness was inverted;
• whether Y was flipped in the normal;
• the intended color-space import setting;
• the target shader and render pipeline.

File format and bit-depth choices

• PNG or TGA: sensible lossless interchange for most 8-bit base color, normal, and mask textures.
• 16-bit PNG, TIFF, or EXR: safer masters for height when visible banding would become geometry.
• JPEG: fine for disposable references, risky for normals and masks because block compression changes the data before the engine even imports it.

The engine will usually create its own runtime compression and mip chain. Your source export should give that importer clean data rather than pre-compressed artifacts.

The five-minute cross-engine preflight

1. Tile the material 3×3 on a plane. Look for seams and unique features that repeat too loudly.
2. Place it on a sphere and beveled cube. Move a hard light to reveal normal orientation and roughness response.
3. Solo each scalar channel. Metallic should describe material category, not random grayscale noise. AO should concentrate in plausible creases. Roughness should explain highlight width.
4. Check the object from gameplay distance. Mipmaps can erase thin masks or make noisy normals sparkle.
5. Compare Blender, Unity, and Unreal under roughly neutral lighting—not three unrelated HDRIs. You are testing data interpretation, not staging a beauty-shot contest.

The export is a contract

A texture set is only “engine-ready” when everyone agrees on what each number means. Generate maps with the PLAYTEX PBR Map Generator, keep the unpacked masters, create explicit presets for each destination, and test the actual shader that ships.

If the material looks wrong after crossing engines, resist repainting it immediately. First ask four boring, productive questions: Is this color or data? Roughness or smoothness? +Y or -Y? Which value lives in each channel? Those four answers solve an astonishing amount of PBR drama.