RWTH Aachen just open sourced the math behind faster AM slicers

The boring math that decides how fast your slicer runs

Behind every print, a slicer has to do a lot of invisible work. It figures out the best angle to lay a part in the build volume, packs as many parts as it can without overlap, slices the geometry into layers, and plans the laser path. That work sounds simple until your part is large, your machine has a dozen lasers, and the file balloons to something a normal computer chokes on. The Institute Digital Additive Production, or DAP, at RWTH Aachen University just made a chunk of that math free for anyone to use.

The release is called DAP-CG, short for DAPComputationalGeometry. It is a C# library that handles the geometry algorithms inside AM CAM software: build orientation, support structure generation, nesting, slicing, and scan strategy calculation. It builds on two well known open source libraries, geometry3Sharp and Clipper2, and adds speed work on top.

Why this matters to more than academics

The interesting part is not that the code exists, it is what it does to memory and time. In an industry project called IDAM, DAP's polygon compression cut the memory needed for nesting by a factor of five. The same idea applied to slicing and scan strategy planning saved a similar amount. In plain terms, that can be the difference between processing a big build job on a 32 GB desktop machine and having to rent a server with several times the memory.

The library also uses modern C# features like Span and SIMD to speed up moving and rotating geometry. For small software teams building their own slicer or print prep tools, that is a lot of hard problems solved for free.

What you can actually do with it

DAP-CG is aimed at people writing CAM software, not at people loading an STL into a consumer slicer. But the ripple effect reaches everyday users. Most slicer makers quietly rebuild these algorithms from scratch, and some do it poorly, which is why large or complex models can take hours to slice. When a respected institute open sources a tested, fast version, the better implementations can spread, and slicing gets quicker across the board.

The part orientation tool inside the library is a good example. It picks the best way to tilt a part based on quality and cost targets, which directly changes how much support material you burn and how strong the result is.

The bottom line

Open sourcing core CAM geometry is a quiet but useful move for the whole additive manufacturing software world. As machines add more lasers and parts get bigger, the old ways of handling geometry will not keep up. DAP just handed smaller developers a faster path, and that should mean snappier tools for the rest of us down the line.