Module 06 · Texture Baking — BlueCat 3D AI × 3D character pipeline

/ 01 · What this step does

Making the low-poly "pretend" to be the high-poly

Picking up from Modules 04 + 05: you have a clean low-poly aligned to the high-poly, plus a good UV unwrap — baking marries the two, cooking the high-poly detail into the textures.

The principle: ray-project the high-poly geometry onto the low-poly surface, record the surface direction per pixel, and store it as a normal map. In-engine, put that map on the low-poly, light it, and it shows every bump of the high-poly — at a fraction of the face count.

Key insight: a normal map can only "fake" surface relief — it can't change the silhouette. So the low-poly's outline has to be right back in Module 04 — baking can't rescue a crooked silhouette.

/ 02 · Which maps you bake

One texture set, feeding the next step

More than just the normal. This set drives the materials and wear effects in Module 07:

Normal: must bake · fakes the high-poly's surface bumps on the low-poly (tangent space)

AO (ambient occlusion): self-shadowed darks in cavities and seams (deepen, dirty up)

Curvature: edge convex/concave info (drives wear, edge highlights)

Material ID: paint each part a flat color (instant per-region select while texturing)

Thickness: light-through / subsurface zones (ears, cloth edges (optional))

Position / Height: gradient / height info (optional, drives procedural effects)

/ 03 · Core principle: cage and rays

A bake lives or dies on the cage

During a bake, rays shoot from the low-poly surface toward the high-poly to sample it. The cage is a slightly inflated copy of the low-poly that wraps the high-poly — it dictates which direction the rays fire and how far.

Use a smooth (averaged) cage: it ignores the low-poly's own normals and projects uniformly from a smoothed direction, so hard edges don't split and leave gaps. This is the recommended approach in most cases.

Set the ray distance to just cover the whole high-poly: too short and the high-poly's protruding parts don't get sampled (black spots); too long and you sample neighboring faces you shouldn't (crosstalk).

/ 04 · Prep you must do before baking

These four things stop 90% of bake errors

Naming pairs

Pair low and high by suffix — character_low / character_high — and the baker (Marmoset Quick Loader / Substance) groups them automatically. Wrong names = no match.

Triangulate the low-poly

Triangulate before baking, and make sure the triangulation matches between the baker and the engine — otherwise the normals go wrong in-engine.

Patch high-poly holes

If the high-poly has holes, rays hit nothing and you get black spots. Seal the holes first.

Apply transforms + align

Apply Transform on both low and high (reset position/rotation/scale), and keep the low-poly snug against the high-poly (already done in Module 04).

/ 05 · Tool routes

Where to bake? Four routes

Marmoset Toolbag

GPU baking, real-time preview, paint cage/skew in the viewport. What-you-see-is-what-you-get, the industry gold standard — our top pick for this section.

Paid · fastest at spotting flaws

Blender built-in

Cycles' Selected to Active bake, with a cage + ray distance. Free and good enough, but no real-time preview — "blind baking" is slower.

Free · all inside Blender

Substance Painter

Bake right inside your texturing app (Bake Mesh Maps). If Substance is your next step, baking there is the least hassle.

Seamless into 07

AI auto-bake

If Module 04 used Meshy/Tripo auto-retopo with baking on, the normal is already generated. Quality is so-so, but fine for background characters.

Fast · so-so quality

/ 06 · Step by step

From pairing to one clean texture set

6.1

Name pairs + import

Name them _low / _high, then import into the baker. Matching names auto-form a single Bake Group. Split a complex character into groups by part (body, weapon, helmet each their own group) so they don't cross-talk.

6.2

Set cage / ray distance most critical

Start with an auto estimate (Marmoset's Estimate Offset / Blender's Extrusion + Max Ray Distance) so the cage roughly covers the high-poly.
Use a smooth cage, then fine-tune Max Offset: just enough to enclose the most protruding parts of the high-poly, no more, no less.
Orbit around and check: any low-poly poking out of the cage, or the cage sitting so far it samples a neighbor.

6.3

Bake the normal first, low-res test

Bake a pass at 1024 first — low res, fast, and the flaws actually show up more clearly.
Get tangent space right: match your engine/Substance (most use MikkTSpace / xNormal-Mikk). Mismatch = blue-tinted normals and blown-out seams in-engine.
Put the normal on the low-poly and hunt for black spots, color fringing, misalignment, and rippling.

6.4

Fix the flaws hand-fix here

Skewed-projection detail: Paint Skew in Marmoset to straighten it live; Paint Offset to tweak cage distance locally.
Black spots: usually a hole in the high-poly or a too-short cage — go back and seal the hole / add distance.
Rippling on curves: the low-poly doesn't have enough segments there — go back to Module 04 and add a few, or add a bevel — a normal can't change the silhouette.
Small floaters: screws, rivets and the like can "float" above the surface and bake separately, saving you high-poly work.

6.5

Bake the rest of the maps

AO: dial Search Distance until seams and cavities have clean darks; for characters, generally turn off Floor Occlusion.
Curvature: push Intensity up a bit for sharper edges, to drive wear in 07.
Material ID: paint each high-poly part a flat color (or use materials), bake the ID map, and select regions by color instantly in 07.

6.6

Output settings + export

Final resolution: hero 2K–4K, secondary characters 1K–2K.
Edge padding (Padding/Dilation): crank it up to stop color bleeding across the seams between UV islands.
Export normals as 8-bit PNG (most engines want 8-bit); for extra smoothness, bake 16-bit then convert.
Naming convention: char_normal / char_ao / char_curv / char_id, filed as a set into 06_bake.

/ 07 · Key discipline

Three iron rules

① The cage decides everything. Nine out of ten bake flaws come from a cage that doesn't wrap properly. Get the cage right before you talk textures.

② Tangent space and triangulation must match the engine. Looks great in the baker but blows out in-engine? Nine times out of ten these two don't line up.

③ Normals fix the surface, not the silhouette. Rippling or a wrong outline is a low-poly/segment problem — go back a step to fix it, don't grind on it in baking.

/ 08 · Common wrecks

These traps only show up in-engine

Cage too short → protruding high-poly parts don't get sampled, a patch of black spots.

Cage too long / parts not grouped → samples neighboring faces, detail crosstalk.

Tangent-space mismatch → blue-tinted normals and weird lighting in-engine.

No triangulation before baking, or a mismatch → wrong, dirty normals in-engine.

Unsealed holes in the high-poly → rays hit nothing, black-hole flaws.

No padding → color bleeds at UV island edges, seams appear.

Counting on normals to fix rippling silhouettes → wasted effort, you have to go back to Module 04 and add segments.

/ 09 · This section's deliverables

Tick these off and you've passed

A clean normal mapNo black spots / crosstalk / seams, correct tangent space

AO / curvature / ID mapsTo drive materials and wear in 07

Normal on the low-poly, detail reads like the high-polyLow-poly + normal = high-poly look

Resolution on spec, ample padding, 8-bit PNGHero 2K–4K

Naming convention, whole set filedchar_normal/ao/curv/id → 06_bake

/ 10 · Self-check before the next step

🐾 Three questions — pass all to proceed

With the normal on the low-poly, does the detail read like the high-poly, free of black spots and color fringing?
Do the tangent space and triangulation match your target engine?
Are AO / curvature / ID all baked, named, and filed?

▸ All three pass → on to Module 07: texturing + materials (◐ AI + hand-fix).