Texturing is four decisions taken in order: whether the model needs UVs, how the UV islands are laid out, which PBR maps you author, and where the pixels come from. Each decision is explained here with the numbers that make it.
Texturing a 3D model is four decisions taken in a row: whether the model needs UVs at all, how those UVs are laid out, which maps you author, and where the pixels come from - painted, baked, downloaded or generated. Take them in the wrong order and an afternoon's work runs into the next week.
This tutorial answers those four questions in order, with the numbers that decide the outcome: texel density targets, cage and ray distances for baking, colour-space rules, and resolution and bit-depth choices. It finishes in the engine the model will ship in, not in the texturing tool.
Texturing problems are rarely about brush skill. They come from a decision skipped earlier: an object unwrapped for a hero shot that now has to run on a phone, a normal map baked against the wrong cage, a roughness map saved as sRGB. Each question below constrains the next.
UVs exist so that a 2D image can be addressed by a 3D surface. If the material is uniform - concrete, brushed steel, a single plastic - a triplanar projection or a procedural node graph in Blender, Substance 3D Designer or Material Maker can drive it with no unwrapping at all. The moment a surface needs one specific mark in one specific place - a decal, a baked logo, a face, a hand-painted scuff - you need UVs, because only a texture map can store the sentence this pixel belongs here.
Unwrapping is the same operation in Blender, Maya, 3ds Max and RizomUV: mark edges as seams, cut the mesh into islands, flatten each island, pack them into the 0-1 square. The habit is to mark seams where the object already breaks - a panel gap, a hem, the back of a leg - so that artefacts land where the eye is not looking. Afterwards, scale the islands to a common density so props stay consistent with the scene.
| Target | Typical resolution | Texel density | Notes |
|---|---|---|---|
| Mobile game prop | 512-1024 px | 5.12 px/cm | Detail comes from the silhouette |
| PC or console prop | 2048 px | 10.24 px/cm | Common default for hero props |
| Hero character or vehicle | 4096 px or UDIM tiles | 20.48 px/cm | Split across UDIM tiles |
| Colour 3D print | 1024-2048 px | 8-16 px/cm | 3MF, GLB or OBJ plus MTL; STL drops it |
| Renders and film stills | 4096-8192 px | 40 px/cm and up | Baked for the final camera distance |
A seam only shows when the pixels on either side disagree. Three habits keep it hidden: run the cut along a hard edge or a concave crease - under the arm, behind the ear, along a bevel; align the UV seam with that edge so the normal split and the UV split coincide; and check for overlapping islands, which Blender's UV editor finds with Select Overlap. Two islands sharing one space receive identical pixels, and any bake against them fights itself.
A physically based material is described by a small set of channels, and you rarely need all of them at once. A painted metal panel may want base colour, roughness, metallic and a normal map; a stylised prop may ship with base colour and a packed mask. Every extra map costs memory, bake time and a shader slot, so decide from how the surface behaves, not from a checklist.
| Map | What it stores | Colour space | Typical format |
|---|---|---|---|
| Base colour (albedo) | Surface colour, no lighting baked in | sRGB | 8-bit RGB, no shadows or highlights |
| Roughness | 0 mirror to 1 fully diffuse | Linear (Non-Color) | 8-bit greyscale, often packed |
| Metallic | Metal or dielectric behaviour | Linear (Non-Color) | 8-bit, near 0 or near 1 |
| Normal | Per-texel direction change that fakes fine detail | Linear (Non-Color) | 8-bit RGB tangent space; 16-bit for extreme gradients |
| Height or displacement | Elevation for parallax or displacement | Linear (Non-Color) | 16-bit when read as geometry |
Almost every PBR shader treats metallic as a switch: 0 for plastic, wood, skin and painted metal, 1 for bare iron, aluminium and gold. Values in between usually come from a map painted by eye, and they reflect like metal while tinting like paint. Roughness is the opposite - the gradient carries the information, and real surfaces commonly run from about 0.2 on a polished edge to 0.8 in a worn corner. Packing roughness, metallic and ambient occlusion into one RGB map is a standard saving, but only if the engine reads the channels you wrote; glTF expects metallic in blue, roughness in green.
| Method | Main tools | Strong at | Ceiling |
|---|---|---|---|
| Hand painting in 3D | Substance Painter, Blender Texture Paint, ArmorPaint, Krita | Stylised characters, unique wear | A hero character can take days |
| Baking high-poly to low-poly | Substance Painter, Marmoset Toolbag, Blender Cycles, xNormal | Sculpted detail on a game-ready mesh | Needs a clean low-poly and a fitted cage |
| Procedural materials | Blender nodes, Substance 3D Designer, Material Maker | Tiling surfaces, terrain, architecture | No precise placement of one mark |
| Scanned PBR libraries | Poly Haven, ambientCG, Fab, Textures.com | Realistic fills and set dressing | Licence and resolution vary per asset |
| AI texturing | Open3DAI, Substance 3D Sampler, Meshy, Rodin | Fast first pass, blocking out | Weaker on lettering and logos |
Most bake failures come down to four things: an inverted normal on the low-poly, a cage that is too tight or too loose, a tangent space that differs from the one the engine builds, or a colour-space setting that converted a normal map to sRGB. When hard edges come out scratched, the fix is usually a softer transition rather than a longer bake: bevel the edge slightly, or split the normals so the baker has somewhere to put the bend.
Model, unwrap, bake, texture, export, then look at it in the engine. Verification matters more than the order: view the asset under flat lighting so illumination does not hide seams; check the small mip levels for bleeding at island borders; and confirm the exported file carries the maps - GLB and glTF embed the base colour texture, OBJ plus MTL references external files, STL carries none, and 3MF can store colour. Open3DAI exports AI textures with the model in GLB, glTF, OBJ, PLY, STL or 3MF and compares connected engines side by side; a reusable UV layout still comes first from Blender, Maya or RizomUV, because unwrapping, retopology and rigging are desktop work.
Engine availability, credit pricing and third-party terms change; verify them on the vendor page before committing a budget. Open3DAI covers text-to-3D, image-to-3D, multiview input, AI texturing, side-by-side engine comparison, export to GLB, glTF, OBJ, STL, PLY and 3MF, 48 format converters, 12 browser tools and a REST API. UV unwrapping, retopology, rigging and CAD-grade parametric modelling stay in a desktop tool; the maps are a starting point that usually needs a manual pass.
It depends on the engine. Some work from multi-view renders and project the result back onto the mesh; others expect an existing UV map, so check what the specific engine needs. A UV layout that another artist can paint on afterwards still comes from an unwrap step in Blender, Maya, 3ds Max or RizomUV.
Match it to the platform and the viewing distance: about 5.12 px/cm is a common mobile target, 10.24 px/cm suits PC and console props, and 20.48 px/cm is the usual range for hero characters and vehicles. The mistake that shows up most often is mixing densities inside one scene, which makes one asset look soft next to another.
Three usual causes: the map was saved as sRGB instead of linear; the DirectX and OpenGL green-channel conventions do not match the engine; or the tangent space used at bake time differs from the one the engine builds. Try flipping the green channel in the import settings first, then check the colour space.
As many as the material needs. Base colour, roughness, metallic and normal cover most hard-surface props; ambient occlusion is often packed into one channel or baked into vertex data; height and displacement are usually reserved for renders and film. Fewer maps means less memory and fewer surprises on mobile.
Only if the target platform cannot afford the polycount. Baking normal, ambient occlusion and curvature maps from the sculpt onto a decimated mesh keeps the detail readable at a fraction of the triangles. For a one-off render, keeping the high-poly and texturing it directly is simpler and often looks better.
Poly Haven and ambientCG publish CC0 material libraries with albedo, roughness, normal and displacement maps. Fab hosts scanned assets under a mix of free and paid licences, and Textures.com runs a daily download allowance. Check the licence per asset rather than per site, and check the available resolutions before building a scene around them.
Only the colour channels travel. STL stores triangles with no material information, so a texture applied in Blender disappears the moment you export STL. Use 3MF, GLB or OBJ plus MTL when the slicer or print service reads colour, and confirm the printer's colour workflow before relying on it.
It varies more than any other step. A simple hard-surface prop built from downloaded materials and one baked normal map can be finished in an afternoon; a hero character with hand-painted wear, several UDIM tiles and 4K bakes is a multi-day job. AI texturing shortens the first pass the most, while final placement stays manual.
Send the same prompt or image to several engines, compare the meshes side by side, then export GLB, glTF, OBJ, STL, PLY or 3MF. Creating an account grants free credits and needs no card.
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