Optimizing Textures
Gantry can convert and compress the textures in your asset before export, reducing file size and GPU memory usage — particularly important for RealityKit delivery on Apple devices.
Opening the Texture Optimization Sheet
Section titled “Opening the Texture Optimization Sheet”Choose File - Optimize Textures to open the optimization sheet. Configure the options and click Apply to process the textures. The result is written as an edit layer and can be undone with ⌘Z.
Output Format
Section titled “Output Format”| Format | Best for |
|---|---|
| PNG | Lossless quality; larger files. Recommended for OpenUSD delivery or continued editing. |
| JPEG | Lossy compression; good for colour textures where minor quality loss is acceptable. |
| AVIF | Modern lossy/lossless format with better compression than JPEG at equivalent quality. |
| KTX2 | GPU-native ASTC compression for Apple hardware. Smallest GPU memory footprint at runtime. Recommended for RealityKit delivery. |
Compression Quality
Section titled “Compression Quality”- Fast — Quick encode with lower quality. Useful for iteration and previewing.
- Balanced — A good tradeoff between encode time and output quality.
- Best — Slowest encode, highest quality. Recommended for final delivery builds.
Maximum Texture Size
Section titled “Maximum Texture Size”Constrains the largest dimension of any texture to the selected value (1024, 2048, 4096, or 8192 pixels). Textures already smaller than the limit are not upscaled. Use this to cap resolution for target devices that don’t benefit from textures above a certain size.
Generate Mipmaps
Section titled “Generate Mipmaps”Mipmaps are pre-computed lower-resolution versions of each texture. They improve rendering quality and performance when a model is viewed from a distance. Enable this for any asset intended for runtime use in RealityKit.
Quality Metrics (PSNR)
Section titled “Quality Metrics (PSNR)”When enabled, Gantry computes the Peak Signal-to-Noise Ratio (PSNR) between each original and converted texture. Higher PSNR values indicate less quality loss. This helps you identify textures where the compression settings cause a noticeable degradation before you commit to exporting.
Color Space
Section titled “Color Space”Set the input and output colour gamuts for the conversion:
- Input gamut — The colour space of the source textures (e.g., Display P3 for wide-gamut assets)
- Output gamut — The colour space to target in the converted textures (typically sRGB for broad compatibility)
Apple Texture Converter
Section titled “Apple Texture Converter”Gantry uses Apple Texture Converter for KTX2/ASTC encoding when it is available on your system. Apple Texture Converter is included with Xcode and delivers the highest quality ASTC compression for Apple hardware.
The sheet shows a green checkmark when Apple Texture Converter is detected, or an orange warning if it is not found. If you see the warning, install Xcode from the Mac App Store to enable Apple Texture Converter. Gantry falls back to an open-source encoder when it is unavailable.