ZBrush Tip: Smart Decimation Workflow for VR/AR Asset Optimization

For VR/AR deliverables, decimate smartly before export to hit budgets without sacrificing silhouette or shading fidelity.

Why Decimation for VR/AR

• Rapidly reduces triangle counts while preserving visual form, ideal for realtime mobile and WebAR constraints.
• Creates lightweight LODs without a full manual retopo pass—great for prototypes, reviews, and crowd/secondary assets.
• Pairs well with baked textures (normal/AO) to retain perceived detail on low-density meshes.

Recommended Workflow (ZPlugin > Decimation Master)

• Duplicate first: In SubTool, duplicate your mesh to keep a pristine, high-res source for future bakes.
• UV/Color strategy:
  • If you have UVs for texture baking, enable “Keep UVs.”
  • If relying on vertex color, enable “Use and Keep Polypaint” to resample color during decimation.
• Pre-process: Run Pre-process Current (or All) so Decimation Master analyzes details.
• Target density: Use the percentage or triangle targets to test multiple densities. Start conservative (e.g., 50–70%), then push lower while checking shading and edges.
• Decimate: Apply Decimate Current (or All) and evaluate the result under varied matcaps and lighting.
• Validate: Inspect silhouettes, tight bevels, and thin features. If hard edges turn mushy, step back or decimate regionally.
• Bake detail: For game/AR pipelines, bake Normal/AO (ZPlugin > Multi Map Exporter) from the original high-res to your UV’d decimated mesh.
• Export: Use FBX or OBJ. Confirm unit scale with your target engine/DCC. For vertex color workflows, verify your pipeline supports FBX color sets.

Practical Tips

• SubTool granularity: Decimate per SubTool for optimal preservation; different materials or silhouette-critical parts deserve higher densities.
• LODs fast: Save multiple decimated versions (e.g., LOD0/1/2) to cover device variability. Keep naming consistent for engine import.
• Animation caution: For deforming characters, prefer proper retopo around joints; use decimation mainly for rigid/hard-surface or static set dressing.
• UV integrity: “Keep UVs” preserves layout but not quad flow—expect triangle-based islands. Re-bake maps after decimation to avoid mismatches.
• Normals/shading: In-engine, use hard/soft edge controls or smoothing groups and tangents. Decimated triangles can shade cleanly with correct normal maps.
• Cleanup first: Run Close Holes and fix flipped normals before pre-processing to avoid artifacts.
• Scale matters: Confirm scale via FBX export/import settings to prevent over-aggressive mip selection and lighting errors in AR.

When to stop reducing

• When silhouette breaks at typical viewing distance in your target headset/phone.
• When normal maps no longer recover lost curvature on glancing angles.
• When UV distortion starts to blur baked details at intended texel density.

For licensing, upgrades, and pipeline advice, connect with NOVEDGE. Looking for ZBrush options and compatible tools for VR/AR? Explore NOVEDGE’s ZBrush listings and ask the NOVEDGE team about best-fit workflows.

You can find all the ZBrush products on the NOVEDGE web site at this page.