Overview

This library provides the fundamental building blocks needed to implement a Computer Aided Design (CAD) package. It is broken into three libraries:

• mycad-geometry
• mycad-topology
• [future] mycad-entity

The mycad-geometry and mycad-topology libaries are completely independent of each other. Their only dependencies are the traditional c/c++ runtimes and standard libraries. You are welcome and encouraged to use either (or both) in your own projects.

Example

Please see the examples directory for samples that fully compile and run. Here are a few highlights:

int main()
{
    // The plan is for mycad-entity to merge the functionalities of
    // mycad-geometry and mycad-topology. Something like this
    std::map<mycad::topo::VertexID, mycad::geom::Point> vertices;
    std::map<mycad::topo::EdgeID, mycad::geom::Line> edges;
    mycad::topo::Topology topo;

    // now the user can draw points, connect them into lines, and then we can
    // tell them later which are joined together.
    mycad::geom::Point p1(10, 10, 0); // similarly p2, p3, p4...

    // NOTE: we get the value directly from the `std::optional` because we are
    // very confident that these calls will succeed. Generally, this should be
    // checked programatically.
    auto l1 = mycad::geom::makeLine(p1, p2).value(); // l2, l3

    auto v1 = topo.addFreeVertex(); // v2, v3, v4

    auto e1 = topo.makeEdge(v1, v2); // e2, e3

    auto chain = topo.joinEdges(e1, e2);
    topo.joinEdges(e2, e3);

    // Here's a visual of what we've created
    //
    //   v4/p4         v1/p1
    // (0, 10, 0)   (10, 10, 0)
    //    ○              ○
    //    │              │
    //    │              │
    //    │e3/l3         │ e1/l2
    //    │              │
    //    │    e2/l2     │
    //    ○ ──────────── ○
    // (0,0,0)       (10, 0, 0)
    //  v3/p3          v2/p2

    auto edges = topo.getChainEdges(chain); // retrieves e1, e2, and e3
    auto [left, right] = topo.getEdgeVertices(e1); // retrieves v1 and v2
    auto left = topo.oppositeVertex(right, e1); // retrieves v1
}

Building

This project can be built using cmake. It uses some c++20 features, so please check your compiler's compatibility with c++20 if you have problems.

If the c++20 stuff is an issue for you, let me know and I can remove it.

mkdir build
cd build
cmake ..
make

If you want to run the unit tests, you'll need to install the Catch2 library. If you don't want to (or can't) install it, then you can have cmake fetch a local copy with:

cmake -DMYCAD_FETCH_CATCH=ON ..

Roadmap

Version	Target Date	Main Feature
v0.3	Nov. 2021	entity can represent a cube
v0.4	Jan. 2022	arc added to geometry - maybe circle
v0.5	Mar. 2022	splitEdge added to topology
v0.6	Jun. 2022	boolean union function added to entity
v0.7	Aug. 2022	boolean subtract function added to entity
v0.8	Oct. 2022	fillet function added to entity
v0.9	Nov. 2022	Topological naming problem from FreeCAD is shown as solved