Start Building

UVs are the contract between Blender and your texture pixels. If texel density wanders between a wall and a floor, Lesson 6 materials will look sharp on one surface and mushy on the next no matter how good your brushwork is. This lesson locks one numeric rule (for example 512 px per meter on kit surfaces) and unwraps the three modules you modeled in Lesson 4.

Course illustration for UV strategy and texel density

Lesson Objective

By the end of this lesson you will have:

  1. A Texel_Scale.md (or sheet tab) stating target resolution, meters-per-texel or pixels-per-meter, and which map size you will author (1024, 2048, etc.)
  2. UV unwraps for one straight wall, one floor tile, and one corner with matched world-scale density on visible game faces
  3. Seams placed in creases, hidden edges, or trim breaks—not across flat hero planes
  4. A checker texture test screenshot showing roughly equal square size across mated surfaces

Step 1: Pick a texel budget and write it down

  1. Choose a base texture size for kit surfaces (common starting point: 2048 for hero walls, 1024 for small trims—you can split later).
  2. Measure one straight wall module in meters (outer width × height of the painted area you care about).
  3. Compute pixels per meter for that face: for example 2048 px / 4 m width = 512 px/m along U.
  4. Copy that ratio to floor tiles and corners so adjacent surfaces feel like one art pass, not two resolutions stitched together.

Pro tip: Store two numbers—authoring resolution and pixels per meter—so when you scale UV islands later, you still know intent.

Common mistake: Normalizing every island to fill 0–1 without checking world scale. Equal UV area does not mean equal texel density on different-sized meshes.

Step 2: Seam strategy that survives stylized lighting

  1. Corners — Put seams on the shortest hidden edge or inside inset creases where stylized shadows break form anyway.
  2. Floors — Prefer seams at tile edges that align with modular cuts; avoid diagonal cuts across large visible quads unless style demands it.
  3. Openings (doors/windows) — Loop select face borders you prepared in Lesson 4 and Mark Seam as one continuous chain where possible so unwrap does not fragment randomly.

Mini challenge: Mark seams only from Edge Select mode with Face Orientation overlay on—confirm normals face out before unwrap.

Step 3: Unwrap and scale islands to your rule

  1. Select all faces that share one material slot for kit base (often walls + floor use different materials later, but density should still match visually).
  2. Unwrap with Angle-Based or Conformal as a start; follow with Minimize Stretch in the UV Editor sidebar if available in your Blender version.
  3. With UV Sync Selection on, scale islands in UV space so a known world distance on mesh maps to a known UV span—use MeasureIt tool, edge length readout, or temporary edge markers at 1 m spacing.
  4. Average island scales across wall and floor where they meet in camera shots from Lesson 1 hero angles.

Pro tip: Apply Scale (Ctrl+A) before final UV lock so edge lengths match export reality.

Step 4: Packing, padding, and texel islands

  1. Pack islands with margin (padding) suited to mipmaps—at least 2–4 pixels at 1024 base, more if you plan aggressive downscale.
  2. Straighten rectangular walls where possible so gradient materials in Lesson 6 do not shear.
  3. Rotate floors so U aligns with tile repeat direction you drew on Lesson 3 plans.

Common mistake: Zero padding packed atlases that bleed at first mip in engine—fix now, not after painting.

Step 5: Checker validation and the texel doc

  1. Add a Checker texture node in Material Preview (or UV grid overlay in Blender 4.x viewport options where available).
  2. Capture three views: wall straight, floor tile, corner junction from Lesson 1 camera A or B.
  3. Paste images into Texel_Scale.md with one paragraph each: target px/m, exceptions (hero props later), and known stretch you accept (organic rocks vs kit walls).

Verification checklist

  • [ ] Wall and floor checkers read similar size where they meet
  • [ ] No seam on the primary silhouette ridge unless documented
  • [ ] UV bounds 0–1 per texture set you plan to author

Troubleshooting

  • Stretch spikes on corners - Split corner into logical cubes first; unwrap each logical block, then repack.
  • Floor repeats look rectangular, not square - Non-uniform scale on UV island; reset scale with uniform S in UV editor.
  • Seams visible in flat shade - Move seam into bevel or add supporting geo so light breaks there naturally.
  • Cannot hit 512 px/m everywhere - Document tier B surfaces (512) vs tier A hero (1024) and keep tier B away from tier A in same frame.

FAQ

Should hero props share the kit texel rule?
Hero pieces often get higher density or their own UV set—still write the rule so interviews are easy.

Do I UV trim sheets in this lesson?
No—Lesson 7 builds trim atlases. Here you only need clean kit islands that can later share a sheet or unique maps.

glTF double-sided UV?
Export rules still want no overlapping islands unless intentional stack for baking—note overlaps in Texel_Scale.md.

Recap

  • You wrote a texel rule before painting anything
  • You unwrapped wall, floor, and corner with shared density intent
  • You packed with padding and validated with checkers

Next Lesson Teaser

Lesson 6: Stylized Material Workflow locks base color, roughness, and normal discipline on these islands—three clear rules per surface type so noise does not eat your readability.

Cross-link: our Blender for Game Assets guide UV and texturing chapters pair well with this pass, and the export validation checklist chapter is worth skimming before you freeze UVs for export tests later in the track.

Bookmark this lesson if you batch unwrap dozens of kit pieces—one written scale saves weeks of mismatched paint.