Paperfold is another flattener for triangle mesh files, heavily based on https://github.com/felixfeliz/paperfoldmodels by Felix Scholz aka felixfeliz. Possible input files are STL, Wavefront OBJ, PLY and OFF. To run this you need to install OpenMesh with python pip. The algorithm of paperfoldmodels consists of three steps: - Find a minimum spanning tree of the dual graph of the mesh. - Unfold the dual graph. - Remove self-intersections by adding additional cuts along edges. Reference: The code is mostly based on the algorithm presented in a by Straub and Prautzsch (https://geom.ivd.kit.edu/downloads/proj-paper-models_cut_out_sheets.pdf).
Unfold and import DXF into InkScape using dxf2papercraft. This is some kind of wrapper extension utilizing kabeja to convert the dxf output from dxf2papercraft into SVG. To make it work you need to install at least java. Works on Windows and Linux. dxf2papercraft itself is a tool to make flattened 2D output from a 3D DXF file. Note that kabeja and dxf2papercraft are really old tools. There might be a lot better solutions out there but this is a good starting point and it basically works :) You might have a look at https://inkscape.org/~MarioVoigt/%E2%98%85dxfdwg-importer and https://inkscape.org/~MarioVoigt/%E2%98%85inkscape-papercraft-unfold-stl too.
This tool converts a STL/OFF/PLY/OBJ into binary STL Format. The STL then gets unfolded (flattened) to make a papercraft model. It utilizes https://github.com/osresearch/papercraft and https://github.com/admesh/admesh Documentation: https://fablabchemnitz.de/display/IFM/Papercraft+Unfold