Convert an STL intended for 3D printing (Z up, mm units) to a USDZ file compatible with Apple's AR Quick Look and ARKit

README.md

This script must be placed in the root folder of the USD tools library provided by Apple on their AR Quick Look Gallery page. Requires assimp to be installed.

Command format: ./stl_to_usdz.sh input_file.stl output_file.usdz

For now, this just inserts the necessary transformations at a hardcoded line number in the USD markup, so compatibility with future versions of usdzconvert is not guaranteed.

stl_to_usdz.sh

#!/bin/bash

BASEPATH=$(dirname "$0")
export PATH=$PATH:$BASEPATH/USD:$PATH:$BASEPATH/usdzconvert;
export PYTHONPATH=$PYTHONPATH:$BASEPATH/USD/lib/python

TEMPDIR=$(mktemp -d)
assimp export "$1" $TEMPDIR/model.obj
usdzconvert $TEMPDIR/model.obj $TEMPDIR/model_orig.usdz
usdcat $TEMPDIR/model_orig.usdz -o $TEMPDIR/model.usda

sed -i.bak "17i\\
    custom double3 xformOp:scale = (0.1, 0.1, 0.1)\\
    uniform token[] xformOpOrder = [\"xformOp:scale\"]
" $TEMPDIR/model.usda

sed -i.bak2 's/Y/Z/g' $TEMPDIR/model.usda

usdzip "$2" --arkitAsset $TEMPDIR/model.usda

Getting this error here with this code:

Error in 'textFileFormatYyerror' at line 3162 in file pxr/usd/sdf/textFileFormat.yy : 'syntax error at 'custom' in </model_orig> on line 17 in file /var/folders/66/6tlfb7r143v805h598hz3pdm0000gq/T/tmp.v1HTtJJR/model.usda

It does export a usdz file, but the file doesn't load.

Helpful script tho :) usdz tools download here.