Here we provide instructions on how to install Szalinski, run it, and change the rules and features of the Caddy language. If you are interested to use Szalinski, please reach out to us!

Setup instructions

Following are the steps for setting up Szalinski from scratch on a different machine that runs Ubuntu 19.10.

• Install rust. Type curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh in the terminal and follow the subsequent instructions. The version we used is 1.41.0. Seehttps://www.rust-lang.org/tools/install for more information.

• Make sure you configure your current shell by typing: source $HOME/.cargo/env (the Rust installation will prompt you to do this).

• Install make by typing: sudo apt-get install make

• Install g++ by typing: sudo apt-get install g++

• Install jq by typing: sudo apt-get install jq

• Install CGAL by typing sudo apt-get install libcgal-dev

• Install OpenSCAD by typing sudo apt-get install openscad

• Install git by typing sudo apt install git

• Install pip by typing sudo apt install python3-pip and then install numpy by typing pip3 install numpy and matplotlib by typing pip3 install matplotlib

Running the tools

• First compile Szalinski by running cargo build --release
• To optimize a 3D model (a .csexp file) with Szalinski, run target/release/optimize path/to/foo.csexp path/to/out/foo.json
• You can also navigate to the Makefile and learn more about how to convert an SCAD file to a .csexp file.

Changing Caddy and modifying the rules

• The Caddy language is defined in cad.rs in the src directory. A simple feature you can add is support for a new primitive or new transformations. You can also change the costs of various language constructs. The definition of the cost function starts at line 267.

• As we described in the paper, to verify the correctness of Szalinski, we evaluate Caddy programs to flat Core Caddy and pretty print to CSG. This code is in eval.rs.

• solve.rs and permute.rs contains code that solves for first and second degree polynomials in Cartesian and Spherical coordinates, and performs partitioning and permutations of lists.

• The rewrites rules are in rules.rs. Syntactic rewrites are written using the rw! macro. Each rewrite has a name, a left hand side, and a right hand side. You can add / remove rules to see how that affects the final Caddy output of Szalinski. For example, if you comment out the rules for inverse transformations, they will not be propagated and eliminated, and therefore the quality of Szalinski's output will not be as good.

Notes and remarks

Szalinski is implemented in Rust. As mentioned in Section 6 of the paper, it uses OpenSCAD to compile CSG programs to triangular meshes, and CGAL to compute the Hausdorff distance between two meshes.