5: Layered Material

Technological concepts & product/pipeline features

Layered master shader as the core of the pipeline

• The speaker argues the master material/shader determines most of the visual approach (roughly “80%”).
• Emphasis: an elegant and flexible shader design improves production speed and efficiency.
• Disclaimer: the speaker is not a professional technical artist—recommendations should be verified with a Technical Artist.

Unreal Engine 5 feature stack (and reality check)

Planned pipeline uses:

• Nanite
• Lumen
• Nanite Static Displacement Mapping

Reality check / pushback on the idea that UE5 removes the need for optimization:

• Nanite/Lumen still require updated rules and workflows.
• Even AAA/AA studios are experimenting and iterating.

Displacement/tessellation choice

• Uses Nanite Static Displacement Mapping instead of Nanite tessellation.
• Claimed visual difference is small, but static displacement works better with Nanite (verified via Triangle/Cluster Viewer).
• Both displacement approaches are described as experimental, with a hope they become fully standard in future UE5.

Material Layers system (UE5)

Uses UE5’s Material Layer / Material Layer Blend system to build layered materials:

• Material Layer: per-layer logic instances (e.g., bricks/mortar/plaster).
• Material Layer Blend: masking/mixing logic with blend parameters.
• Master Material container: combines everything and provides global logic.

Example global logic in the master material

• Rebuild/adjust normal map components in one place (e.g., “restore Z-vector” once).
• Optional procedural effects (e.g., adding snow without requiring separate layers).

Material Layer Instances as “Layer Stack”

• The material instance (sometimes called a Material Layer Stack) is where layer parameters are controlled.
• Layer instances can share the same underlying master layer logic while using different textures/parameters.

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Geometry + texture inputs used for the demo

Example asset: simple architectural column

• Separate top/bottom areas.
• Thin beveled edges.
• UVs included.

Two UV channels

• UV0: tileable texture layout, with stated texel density ~1024 (portfolio target).
• UV1: unique RGBA splat mask (splat map) UVs in 0–1 space, no overlaps.
  • Distortion is tolerated because the splat map drives blending only.

Tiny corner chipping

• Used to test how well displacement handles small surface details.

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Layer color pipeline: Gradient Map via Curve Atlas

Gradient-driven base color

• Layer color uses a Gradient Map concept driven by a Gradient Curve Atlas.

Curve Atlas workflow

1. Create a Curve Linear Color defining a black→white gradient with editable color points.
2. Bake it into a Curve Atlas texture (configured as 16×1 pixels).
3. Sample the curve atlas in the material to produce per-layer base color.

Optimization note:

• In the final build, the approach relies on small baked textures—effectively 16×1 textures for the color data.

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Height-blended layer mixing (splat mask + height comparison)

Splat mask blending method

• Blending uses an RGBA splat mask (not vertex painting).
• Channel selection controls which pair of layers the brush/mask edits.

Height blending logic

• The blend mask is computed by comparing height maps from:
  • the lower layer
  • the upper layer

Blend controls:

• Channel intensity: splat mask grayscale controls influence of height blending.
• Softness: adjusts hardness/contrast of the blend boundary; described as sensitive (too high can invert or break expected blending).
• Opacity controls for different attribute groups:
  • opacity for color/roughness together
  • separate opacity for normals
  • separate opacity for displacement

Manual painting behavior

• Painting with different grayscale values changes where the “top layer” appears:
  • based on height recesses vs peaks
• Supports tools such as:
  • shift-delete (remove layer)
  • erasing
  • fill

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“Full” layers vs “Soft” layers

Layer types

• Full layers: standard blending with full normals/displacement behavior.
• Soft layers: reduced influence / simplified behavior.

Practical example: soft grunge normal issue

• Problem: grunge soft layer normal overlapped lower layers and looked flat.
• Fix: set normal opacity to 0 so only roughness/color effects remain clean.

Under-the-hood description

• Soft layers are described as simplified versions of full-layer logic, using fewer textures/controls.

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Technical art optimization goal: reduce draw calls (UE5.5 “Texture Color”)

The draw call problem

• Changing meshes/textures/shader parameters can increase CPU→GPU command overhead, hurting performance.

Why classic splat masks can hurt

• If each unique painted mask requires distinct material instance parameter sets (e.g., swapping splat mask), it can increase draw calls.

UE5.5 solution described

• Uses Virtual Splat Map / Mesh Paint Texture Object + Mesh Paint Texture Replace.
• Adds Texture Color painting backed by virtual textures so the same material instance can be reused while the blend map updates per mesh procedurally.

Texture Color painting setup

• Painting mode adds a Mesh Paint Texture (virtual texture) visible in mesh instance details.
• Requires enabling virtual texture support and specifying:
  • override UV channel index
  • virtual texture resolution

Claimed benefits

• Different painting per mesh, but same material instance enables single draw call across meshes sharing the layer stack.
• Blending looks consistent near-to-far compared to vertex-color blending.

Speaker’s drawback

• The virtual texture is procedural and stored in external actor data, not easily exportable/savable to the Content Browser.
• The speaker needs editable baked textures for:
  • static displacement mapping
  • debugging workflows
  • baking blended results on demand

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Why they revert to “Splat masks” in this project

Even though UE5.5’s texture-color/virtual-texture system is described as more advantageous, the speaker chooses the older splat-mask method because:

• They need a workflow where blend results can be baked into a real texture (on demand, per mesh).
• Virtual textures can’t be saved directly in the UI.
• Manual exporting/baking is too time-consuming.
• The next step (next video) on displacement likely depends on having editable baked blend textures.

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Key tutorial/review-like takeaways (what the video teaches)

• How to build a layered master material with UE5 Material Layers:
  • layer logic in Material Layer functions
  • mixing logic in Material Layer Blend functions
  • global controls in Master Material
• How to set up blending with:
  • two UV channels
  • RGBA splat mask
  • height-map comparison with controllable softness
• How to implement Curve Atlas as a compact gradient/color system (16×1 baked).
• How to handle soft layers using per-attribute opacity (especially normal opacity).
• How UE5.5’s Texture Color painting (virtual textures) can reduce draw calls.
• Why virtual texture blending wasn’t adopted here: difficulty baking/exporting editable textures needed for displacement.

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Main speakers / sources

• Main speaker: An environment/level artist (narrator) teaching the layered material + blending workflow in Unreal Engine 5.
• Source references mentioned:
  • Unreal Engine 5 documentation/features
  • UE5.5 “Texture Color” / mesh paint virtual texture workflow
  • general height-blending math (referenced, not claimed as authored by the speaker)