opencascade-hs

This repository contains multiple libraries, the main two are "OpenCascade-hs" and "Waterfall CAD".

A third party Haskell wrapper to Open CASCADE (wiki), which is the underlying framework behind FreeCAD.

Wrapping the Open Cascade API has been done on an incremental basis, and only a partial subset has been extracted, this largely consists of the modeling functionality (BRep/Boolean Ops/Curves/etc), and does not include the visualization components.

Waterfall CAD is a declarative CAD/Solid Modeling library.

This uses opencascade-hs as the kernel, but provides a "more functional" API over it.

Waterfall CAD SVG

Waterfall CAD SVG adds support for converting Waterfall objects to/from SVG.

It uses the library svg-tree.

It's packaged as a separate library to Waterfall-CAD.

Waterfall CAD Playground

The repo also contains a WASM based interactive playground, hosted at doscienceto.it/waterpark.

The playground lets you try Waterfall-CAD in your browser, without installing anything locally.

It can also be used to view Waterfall-CAD models in a format that allows people to easily make small changes.

This can be built using the Dockerfile in Dockerfile.playground, and developed using the devcontainer in .devcontainer/playground.

Installing Dependencies

OpenCASCADE-hs depends on Open Cascade version >= 7.8.x. In order to run with an earlier version of Open Cascade, you'll need to use a version prior to 0.3.0.0.

OpenCASCADE-hs is only tested on Debian and MacOS.

Linux

As this library depends on OpenCASCADE, I've been developing on Debian with the following packages installed:

> sudo apt-get install libocct-data-exchange-7.9 libocct-data-exchange-dev libocct-draw-7.9 libocct-draw-dev libocct-foundation-7.9 libocct-foundation-dev libocct-modeling-algorithms-7.9 libocct-modeling-algorithms-dev libocct-modeling-data-7.9 libocct-modeling-data-dev libocct-ocaf-7.9 libocct-ocaf-dev libocct-visualization-7.9 libocct-visualization-dev occt-misc

I think there should be some flexibility as to the exact version of libocct required, and which occt packages are necessary.

MacOS

On MacOS, you should be able to install OpenCASCADE via homebrew:

brew install opencascade

MacOs Intel support:

You'll also need to configure the path to the OpenCASCADE header files, either via extra-include-dirs, or CPATH:

export CPATH=$CPATH:$HOMEBREW_PREFIX/Cellar/opencascade/7.*/include/opencascade/

MacOs Apple Silicon support:

In addition to configuring the path to the OpenCASCADE header files, you'll also need to add the libraries to the link and runtime library search paths, either via extra-lib-dirs or LIBRARY_PATH:

export CPATH=$CPATH:$HOMEBREW_PREFIX/Cellar/opencascade/7.*/include/opencascade/
export LIBRARY_PATH=$LIBRARY_PATH:`echo $HOMEBREW_PREFIX/Cellar/opencascade/7.*/lib`

Quick Start

Waterfall-CAD is first and foremost a Haskell library, so you can use it in a Haskell project like any other dependency. For small standalone models, cabal scripts or stack scripts work well, because they let you keep an entire design in a single file.

The workflow I use when designing a model is to have the code write out a solid using writeSTL, and to keep that file open in a mesh viewer (I use MeshLab).

Licensing

Because OpenCASCADE is licensed under the LGPL version 2.1, I'm also using that library for this project.

Get in Touch

If you're having any problems using either of these libraries, please feel free to open an issue.

If you've found the project useful, or interesting, or if you've built anything with it, I'd love to hear from you: there's a Waterfall-CAD Discord server.