3D Model Creation Standards

This document defines the technical requirements and optimization standards for 3D models used in XenseAR environments.

1. File Format & Size Limits

Supported Formats

ℹ️ Info

• .GLB files are loaded directly at runtime.
• .OBJ and .FBX files are packaged into AssetBundles before deployment.

File Size Limits

ℹ️ Info
A Scene refers to the visible content area rendered on the device screen.

💡 Tip
Optimizing texture resolution significantly reduces overall model size.

2. Model Technical Specifications

Topology

Node Count

• Single model: ≤ 20 (recommended: ≤ 5)
• Entire scene: ≤ 200 (recommended: ≤ 10)

Triangle Count

• Single model: ≤ 50,000 (ideal: 4,000 – 15,000)
• Entire scene: ≤ 300,000 (recommended: ≤ 100,000)

Reference Polygon Ranges

3. General Model Requirements

Naming Convention

• Use only:
  • Letters (A–Z, a–z)
  • Numbers (0–9)
  • Underscore (_)
• No spaces or special characters.

Pivot & Alignment

• Pivot must be:
  • At model center or
  • At bottom center (for ground placement)
• Position at world origin: (0,0,0)

Geometry Rules

• Use triangles or quads
• Avoid:
  • N-gons
  • Non-manifold geometry
  • Hidden internal faces

Reset Transform

Before export:

• Scale = 1
• Rotation = 0
• Position = 0

Real-World Scale

• Model scale must match real-world proportions.
• Unit system: Meters

⚠️ Warning
Incorrect scaling may result in improper AR placement.

4. UV Mapping Requirements

To ensure correct rendering and optimal performance in Unity-based AR applications for AR glasses, all 3D models must comply with the following UV mapping requirements.

Requirements

• Every mesh must contain UV Channel 0 (UV0) for mapping textures such as Base Color, Metallic, Roughness, and Normal Map. Models without UV0 will not be accepted.
• All UV coordinates must remain within the 0–1 UV space. UDIM workflows or UV tiles outside the 0–1 range are not supported.
• UV Islands must not overlap, except for intentional Mirror UV usage where overlapping does not affect visual quality.
• UVs must be properly unwrapped with minimal UV stretching, and Texel Density should remain consistent across the entire model to ensure uniform texture quality.
• UV Islands must have sufficient padding to prevent texture bleeding when mipmaps are generated.
• Minimize the number of UV islands and unnecessary seams to improve texture quality and optimize rendering performance.
• Models using Normal Maps must not contain flipped UVs.
• When using Normal Maps, the model must be exported with both Normals and Tangents.
• The use of Texture Atlases is strongly recommended so that multiple objects can share a single material, reducing draw calls and improving rendering performance.
• UV Channel 1 (UV1) is only required for models using Baked Lighting/Lightmaps. For AR applications using Realtime Lighting, UV1 is not required.

Recommended UV Padding

Acceptance Criteria

A model is considered compliant when it meets all of the following requirements:

• Contains a valid UV0.
• All UV coordinates are within the 0–1 UV space.
• No UV overlap, except for approved mirrored UV layouts.
• No UV stretching or flipped UVs.
• Consistent Texel Density across the entire model.
• UV island padding meets the recommended values for the target texture resolution.
• Normals and Tangents are exported when using Normal Maps.
• Meets Unity performance optimization requirements for AR glasses applications.

5. Materials & Textures

Technical Requirements

• Shader: Use default URP (Unity Universal Render Pipeline) shaders.
• Do not embed textures inside .FBX files.
• Keep textures as separate files for Unity import.

Supported Material Workflows

• PBR:
  • Metallic–Roughness
  • Specular–Glossiness
• Unlit materials (if required)

⚠️ Warning
Excessive material count increases draw calls and reduces runtime performance.

6. Animation Standards

Technical Requirements

• Frame rate: 30 FPS
• Each vertex: ≤ 4 bone influences
• Animation must:
  • Start at frame 0
  • Use relative positioning (no absolute coordinates)
  • Be loopable if long-duration

⚠️ Warning
Improper rigging or excessive bones may cause performance degradation on mobile AR devices.