4: Texture Packing

Summary (Texture Packing & Master Material Setup)

The video focuses on preparing environment shading materials by breaking down surface materials into a small number of layers (≤4) and then packing multiple texture maps into combined texture assets to save memory and improve performance.

It covers:

• Selecting/defining material layers (brick, mortar, plaster, dirt, plus procedural snow)
• Downloading Megascans texture sets and processing them in Substance Designer
• Packing channels into Unreal Engine 5–friendly textures using RGBA
• Using a gradient-map color workflow (instead of per-layer base color textures)
• Fixing common tiling/repetition artifacts in Megascans materials
• Building packed maps for Unreal shader use, including special handling of normal maps and channel reconstruction

Artistic Techniques / Concepts Shown

Layered material decomposition

• The surface is decomposed into constituent layers with no more than four core material types (plus an extra procedural layer).
• Planned layers:
  • Brick
  • Mortar (separate layer)
  • Plaster
  • Dirt/rust stains
  • Snow (procedural)

Snow is handled as an extra procedural layer rather than a texture-based layer.

Procedural snow layer (no textures)

• Snow is generated by mixing:
  • white color + roughness
• The mixing uses a top/vector-based function with manual artistic control.
• This procedural result is integrated into the final shading stack as a purely procedural layer.

Texture packing for performance

• Instead of using separate textures (base color, roughness, AO, height/displacement), the workflow packs multiple maps into RGBA channels.
• It uses Substance Designer RGBA blending to merge grayscale inputs into a single exported texture.

Gradient-mask color workflow (performance + control)

• The artist avoids using a standalone base color texture inside the shader.
• A grayscale gradient mask is colorized using a gradient map node:
  • adjusting black/white positions in the gradient replaces them with chosen colors
• Framed benefits:
  • Better performance (fewer 2K textures per layer)
  • Greater flexibility for color iteration directly in-editor

Normal-map channel packing & reconstruction

• Normal maps are split into RGB channels using RGB split.
• The workflow reconstructs the missing channel in Unreal:
  • It uses two existing channels (R and G) and reconstructs B (Z component) in the shader.
• Packed channel assignment:
  • Normal green channel → packed green
  • Normal red channel → packed alpha
• Mentions the importance of specific bias/scale parameters to ensure correct reconstruction.

Tiling artifact correction for Megascans

• Repetition issues are detected visually (e.g., square black blocks).
• Uses “Make It Tile Photo” in Substance Designer:
  • shifts texture samples multiple times
  • creates blending masks to smooth repetition
  • adjusts parameters to improve transition quality

Texture value conditioning for realism

To avoid overly localized peaks and washed-out results, the workflow:

• Uses Levels to increase or normalize contrast/range.
• Attempts to normalize height maps so the average height matches mid-gray (≈ 127.5 on 0–255).
• Builds a cleaner AO:
  • rather than relying on noisy Megascans AO
  • uses ray-traced AO in Substance Designer to generate better occlusion for mortar.

Step-by-Step Workflow / Process (As Described)

1) Define material layers (concept breakdown)

• Determine planned surface constituent materials:
  • brick
  • mortar (separate)
  • plaster
  • dirt/rust stains
  • snow (procedural, textureless)
• Keep the layered approach efficient:
  • core layers limited to ~4, with snow added as an extra procedural mix.

2) Prepare Megascans textures in Substance Designer

• Import textures into a Substance Designer project:
  • base color (or grayscale mask source)
  • displacement/height
  • roughness
  • ambient occlusion

3) Create the main packed texture (“grah” = gradient/roughness/AO/height)

• Convert base color source to grayscale.
• Increase contrast using Levels to improve gradient colorization results.
• Pack maps into one RGBA texture using an RGBA blending node:
  • R channel / packed content depends on the exact setup
  • intent: pack gradient mask + roughness + AO + height into one asset
• Export packed texture in TGA format (named “grah” in-engine).

4) Fix repetition/tile quality

• Apply Make It Tile Photo to individual textures (especially noisy materials like plaster/mortar).
• Keep parameters consistent across inputs.
• Adjust settings until repetition artifacts (e.g., square black blocks) are reduced.

5) Build the second packed texture for normals/metallic (“MN”)

• Split normal map channels with RGB split.
• Pack:
  • normal G → packed G
  • normal R → packed alpha
• Fill remaining channel needs:
  • metallic set to 0 (black) since this material instance doesn’t use metallic
  • blue channel left unused / for future generic noise/gradient work
• Export the second packed texture in TGA format.

6) Reconstruct normal map in Unreal

• In Unreal material nodes:
  • recompute the blue (Z) component from the packed red/green channels
  • use correct bias/scale constants for accurate results
• Credit a community method for the reconstruction approach.

7) Additional mortar-material tuning

• Adjust normal intensity to better match the intended look.
• Fix displacement/height distribution:
  • raise levels slightly to spread peaks
• Normalize height map:
  • target average around mid-gray
  • verify by blurring to visually check mean value
• Replace noisy AO:
  • generate cleaner AO using ray-traced ambient occlusion
• Modulate roughness:
  • reduce/alter overly opaque roughness values if needed

Creators / Contributors Credited

• Brian LeLaw — credited as the author of a normal reconstruction method referenced via Experience Points Discord (Tech Art channel).