Gaussian Splat Optimizer Skill

Gaussian Splat Optimizer

Optimize 3D Gaussian Splatting scenes for real-time rendering on Apple platforms (iOS, macOS, visionOS) using Metal.

When to Use

Optimizing .ply or .splat files for mobile/Apple GPU targets
Reducing gaussian count for performance (pruning strategies)
Implementing Level-of-Detail (LOD) for large scenes
Compressing splat data for bandwidth/storage constraints
Profiling and optimizing Metal rendering performance
Targeting specific FPS goals on Apple hardware

Quick Start

Input: Provide a .ply/.splat file path, target device class, and FPS target.

# Analyze a splat file
python ~/.claude/skills/gsplat-optimizer/scripts/analyze_splat.py scene.ply --device iphone --fps 60

Output: The skill provides:

Point/gaussian pruning plan (opacity, size, error thresholds)
LOD scheme suggestion (distance bins, gaussian subsets)
Compression recommendation (if bandwidth/storage bound)
Metal profiling checklist with shader/compute tips

Optimization Workflow

Step 1: Analyze the Scene

First, understand your scene characteristics:

Gaussian count: Total number of splats
Opacity distribution: Histogram of opacity values
Size distribution: Gaussian scale statistics
Memory footprint: Estimated GPU memory usage

Step 2: Determine Target Device

| Device Class | GPU Budget | Max Gaussians (60fps) | Storage Mode | |-------------|-----------|----------------------|--------------| | iPhone (A15+) | 4-6GB unified | ~2-4M | Shared | | iPad Pro (M1+) | 8-16GB unified | ~6-8M | Shared | | Mac (M1-M3) | 8-24GB unified | ~8-12M | Shared/Managed | | Vision Pro | 16GB unified | ~4-6M (stereo) | Shared | | Mac (discrete GPU) | 8-24GB VRAM | ~10-15M | Private |

Step 3: Apply Pruning

If gaussian count exceeds device budget:

Opacity threshold: Remove gaussians with opacity < 0.01-0.05
Size culling: Remove sub-pixel gaussians (< 1px at target resolution)
Importance pruning: Use LODGE algorithm for error-proxy selection
Foveated rendering: For Vision Pro, reduce density in peripheral view

See references/pruning-strategies.md for details.

Step 4: Implement LOD (Large Scenes)

For scenes exceeding single-frame budget:

Distance bins: Near (0-10m), Mid (10-50m), Far (50m+)
Hierarchical structure: Octree or LoD tree for spatial queries
Chunk streaming: Load/unload based on camera position
Smooth transitions: Opacity blending at chunk boundaries

See references/lod-schemes.md for details.

Step 5: Apply Compression (If Needed)

For bandwidth/storage constraints:

| Method | Compression | Use Case | |--------|-------------|----------| | SOGS | 20x | Web delivery, moderate quality | | SOG | 24x | Web delivery, better quality | | CodecGS | 30x+ | Maximum compression | | C3DGS | 31x | Fast rendering priority |

See references/compression.md for details.

Step 6: Profile and Optimize Metal

Choose storage mode: Private for static data, Shared for dynamic
Optimize shaders: Function constants, thread occupancy
Profile with Xcode: GPU Frame Capture, Metal System Trace
Iterate: Measure, optimize, repeat

See references/metal-profiling.md for details.

Key Metrics

| Metric | Target | How to Measure | |--------|--------|----------------| | Frame time | 16.6ms (60fps) | Metal System Trace | | GPU memory | < device budget | Xcode Memory Graph | | Bandwidth | < 50GB/s | GPU Counters | | Shader time | < 10ms | GPU Frame Capture |

Reference Implementation

MetalSplatter is the primary reference for Swift/Metal gaussian splatting:

Repository: https://github.com/scier/MetalSplatter
Supports iOS, macOS, visionOS
~8M splat capacity with v1.1 optimizations
Stereo rendering for Vision Pro

Getting Started with MetalSplatter

git clone https://github.com/scier/MetalSplatter.git
cd MetalSplatter
open SampleApp/MetalSplatter_SampleApp.xcodeproj
# Set to Release scheme for best performance

Agent Skills: Gaussian Splat Optimizer

Install this agent skill to your local

Skill Files