83 added, 40 removed. Audit A to A.
---
name: blender-modeling
group: 3D assets
description: >-
Model, retopologise, UV unwrap and bake game-ready assets with correct scale, pivots and
polycount. Use when creating 3D hard-surface meshes, low-poly props, or UV layouts.
---
- # Blender Modeling
- Model, retopologise, UV unwrap and bake game-ready assets with correct scale, pivots and polycount..
+ # blender-modeling
- ## Process
+ ## Core Philosophy
+ 3D modeling for real-time video games is not creating unconstrained digital sculptures. A high-poly model with 4,000,000 polygons and 12 un-optimized material slots will crash a game engine. Real-time 3D art is the rigorous craft of geometric efficiency: sculpting high-fidelity details, retopologizing into clean low-poly game meshes, baking high-to-low normal maps with zero shading artifacts, establishing consistent texel density, and enforcing strict transform hygiene.
- 1. **Intake & Scope Definition**
- - Identify specific objectives, inputs, constraints, and operational context.
- - Inspect existing project documentation, configurations, or relevant repository assets.
+ ---
- 2. **Analysis & Strategic Formulation**
- - Evaluate options against best practices, security posture, and domain requirements.
- - Deconstruct complex components into discrete, actionable phases.
+ ## 4-Step Game-Ready 3D Modeling Pipeline
- 3. **Execution & Synthesis**
- - Produce structured, production-grade deliverables matching the required format.
- - Ground all recommendations in concrete project evidence rather than abstract generalities.
+ ### Step 1: High-Poly to Low-Poly Modeling & Retopology
+ 1. **High-Poly Sculpting / Hard-Surface**:
+ - Model complete micro-details: bevels, screws, seams, welded joints, cloth folds.
+ 2. **Low-Poly Retopology Discipline**:
+ - Silhouette is King: Allocate polygon budget to the **outer silhouette** where curved edges meet the sky/background. Flat surfaces require minimal geometry.
+ - Clean Edge Loops: Quad-dominant topology along deformation joints; triangulate flat surfaces before export to prevent engine-specific triangulation warping.
+ - Polycount Budgets:
+ - Hero Character: 30k–60k triangles.
+ - First-Person Weapon: 15k–30k triangles.
+ - Environment Prop: 1k–5k triangles.
- 4. **Review & Refinement**
- - Validate against the verification checklist and domain edge cases.
- - Highlight open questions, explicit trade-offs, and next milestones.
+ ### Step 2: UV Unwrapping & Texel Density Standardization
+ 1. **The Texel Density Constant**:
+ - Standardize pixel density per meter across all assets in the game world:
+ - Hero First-Person Props: **2048 px/m** (4K texture for 2m object).
+ - Standard Characters / Weapons: **1024 px/m** (2K texture for 2m object).
+ - Environment Props / Architecture: **512 px/m**.
+ 2. **UV Seam Placement & Packing Hygiene**:
+ - Place UV seams in concealed areas (undersides, inner seams, sharp mechanical angles).
+ - Packing Efficiency: Achieve **$\ge 75\%$ UV space utilization**. Pack UV islands with at least **16px padding** (at 2K resolution) to prevent mipmap texture bleeding.
- ## Deliverable & Output Format
+ ### Step 3: Normal Map Baking & Shading Seam Prevention
+ 1. **The 3 Golden Rules of Baking**:
+ - *Rule 1: Hard Edges Require UV Seams*: Any sharp edge ($> 60^\circ$ angle) marked with a Hard/Sharp Edge **must** have a corresponding UV seam split to prevent dark shading gradients across normal maps.
+ - *Rule 2: Triangulate Before Baking*: Triangulate the low-poly mesh prior to baking to guarantee the normal map is baked against the exact triangulation the engine renders.
+ - *Rule 3: Use Average Normals & Cage*: Use an expanded cage mesh to prevent projection ray intersection clipping on tight mechanical crevices.
- ### 📋 Executive Summary
- - **Objective:** Key goal addressed
- - **Status:** Complete / Action Required
- - **Primary Recommendation:** Core actionable conclusion
+ ### Step 4: Transform Hygiene & Export Configuration
+ 1. **Transform Normalization**:
+ - Apply all transforms: Location `(0,0,0)`, Rotation `(0,0,0)`, Scale `(1.0, 1.0, 1.0)`.
+ - Set Origin Point: Place the origin pivot at the logical physical base (e.g. bottom-center of props for easy ground snapping, or center-of-mass for physics debris).
- ### 🛠️ Detailed Implementation / Analysis
- - Concrete technical, operational, or strategic specifications.
- - Clear code, configuration, or documentation blocks where applicable.
+ ---
- ### 📌 Decisions & Next Steps
- - [ ] Immediate action items with designated owners.
- - [ ] Required dependencies or prerequisite milestones.
+ ## Deliverable Format: 3D Asset Specification (`ASSET-SPEC.md`)
- ## Instructions & Operating Rules
+ ```markdown
+ # Real-Time 3D Asset Specification: [Prop Name]
- - Lead directly with actionable findings and structured results.
- - Never introduce speculative abstractions or unrequested complexity.
- - Maintain consistency with existing architecture and naming conventions.
- - Provide explicit rationales for non-obvious trade-offs.
+ ## 1. Geometric Budget & Dimensions
+ - **Asset Name**: Tactical First-Aid Station Prop
+ - **Physical Dimensions**: 0.6m (W) x 0.8m (H) x 0.25m (D)
+ - **Target Polygon Count**: 3,200 triangles (Budget: <= 4,000 triangles)
+ - **Topology**: 100% clean manifold geometry; zero ngons; zero loose vertices.
- ## Verification & Quality Checklist
+ ## 2. UV & Texel Density Standards
+ - **Texture Set Size**: 2048x2048px (PBR Metallic/Roughness workflow)
+ - **Target Texel Density**: 1024 px/meter
+ - **UV Island Padding**: 16px minimum gutter spacing
+ - **UV Space Efficiency**: 79.4% packed area
- - [ ] Deliverable directly satisfies all stated user requirements and criteria.
- - [ ] Edge cases, boundary conditions, and error states are addressed.
- - [ ] Output contains zero placeholder tokens, broken references, or unverified claims.
- - [ ] All cross-references and formatting comply with repository conventions.
+ ## 3. Texture Map Manifest
+ | Map Type | Channel Packing | Format | Bit Depth |
+ |---|---|---|---|
+ | Base Color / Albedo | RGB | PNG / TGA | 8-bit sRGB |
+ | Normal Map | RGB (OpenGL / DirectX) | PNG / TGA | 16-bit Linear |
+ | ORM Map | R: Occlusion, G: Roughness, B: Metallic | PNG / TGA | 8-bit Linear |
- ## Anti-Patterns & Constraints
+ ## 4. Transform & Pivot Setup
+ - Pivot Point: Bottom-center at `(0, 0, 0)`.
+ - Applied Scale: `(1.0, 1.0, 1.0)` confirmed.
+ ```
- - **NEVER** output generic boilerplate without grounding in specific project inputs.
- - **NEVER** silently omit unresolved contradictions or unverified assumptions.
- - **NEVER** make unrequested modifications outside the stated deliverable boundary.
+ ---
+
+ ## Worked Example: Eliminating Black Normal Map Seams
+
+ - **Problem**: Hard-surface weapon model exhibited ugly dark shading gradients along mechanical edges when imported into Unreal Engine.
+ - **Diagnosis**: 90-degree bevel edges were marked as smooth without UV seams, forcing the normal map to compensate for extreme vertex normal bending.
+ - **Fix**: Marked 90-degree edges as Sharp; split UV islands along those exact edges; re-baked with cage.
+ - **Result**: Shading rendered completely seamless and flat under real-time lighting.
+
+ ---
+
+ ## Verification Checklist
+
+ - [ ] All transforms applied (Scale is strictly 1.0; rotation is 0,0,0).
+ - [ ] Pivot origin positioned at logical attachment/ground point.
+ - [ ] No ngons (faces with $> 4$ vertices) or non-manifold geometry present.
+ - [ ] Texel density verified consistent with project standards.
+ - [ ] Hard/sharp edges correspond 1:1 with UV seam boundaries.
+
+ ---
+
+ ## Anti-Patterns
+
+ - **Leaving Unapplied Scales**: Exporting an asset scaled at 0.05, breaking real-time physics and distance culling.
+ - **Wasted UV Texture Space**: Packing UVs with 40% empty white space, wasting texture VRAM.
+ - **Baking Without UV Padding**: Setting 0px gutter margin between UV islands, causing colors to bleed across LOD mipmaps.