Four files, one bike
All four files are on this site, made from lumen-bike.glb with glTF Transform 4.5.1. The last one used optimize's defaults (joining on).
glTF Transform shrinks the exported bike from 1.3 MB to 34 KB: Draco or Meshopt compress the geometry, WebP or KTX2 the textures. Compressed files need a decoder, and the default settings can merge your named parts.
Change the code and press Run (Ctrl+Enter). Predict what will happen first, then break it on purpose and read what changes. Your edits are saved and match the lesson page.
Ready for more? This phase has 4 hands-on exercises with automatic checks.
Practice questions
Write the code in the editor, run it, then open the model answer to compare.
Write the GLTFLoader setup that can load Draco, Meshopt and KTX2 files from this course's decoder folders.
A teammate's model is 8 MB, mostly four 4096 × 4096 PNG textures. List the commands or steps to make it phone-friendly, and the GPU memory before and after.
Explain it without notes
Compare Draco and Meshopt for the showroom: size, speed and what each needs.
Why did the course turn off joining when it compressed the bike?
Console
Nothing logged yet.Expected console output
lumen-bike.glb 1294.5 KiB | draw calls 25 | triangles 8168 | parts found by name 6 of 6
lumen-bike-meshopt.glb 46.5 KiB | draw calls 25 | triangles 8168 | parts found by name 6 of 6
lumen-bike-draco.glb 33.0 KiB | draw calls 25 | triangles 8168 | parts found by name 6 of 6
lumen-bike-draco-joined.glb 31.5 KiB | draw calls 7 | triangles 8136 | parts found by name 1 of 6