Graphite is an in-development raster and vector graphics package that's free and open source. It is powered by a node graph compositing engine that fuses layers with nodes, providing a fully nondestructive editing experience. https://graphite.rs/
OSAFE Workbench (FreeCAD addon) https://github.com/ebrahimraeyat/OSAFE
The OSAFE workbench by Ebrahim Raeyat. This FreeCAD Addon is a collection of civil engineering tools, originally designed as a workaround for issues with CSI SAFE. The addon is available via the regular Addon Manager.
GPL-V3
Just reviewing this thread regarding OS and Free software. Although not specifically AEC software but for myself and others that plan to record video tutorials and post edit, Blackmagic offers a world class video editing application called Davinci Resolve. Fantastic application and very open community.
Free and open source NURBS Modeller.
License: BSD https://ayam.sourceforge.net/
Ayam is a free 3D modelling environment for the RenderMan interface, distributed under the BSD licence.
The current stable version is 1.33, released 25. Jul 2023.
Ayam currently runs on Unix (Linux, IRIX, FreeBSD tested), Win32 (Win95-Win2000, XP, 7), and Mac OS X (Aqua and X11).
Ayam features at a glance:
RIB (RenderMan Interface Bytestream) export and import.
Support for NURBS curves and (trimmed) NURBS surfaces, Boxes, Quadrics (Sphere, Disk, Cylinder, Cone, Hyperboloid, Paraboloid, and Torus), CSG, MetaBalls, Patch Meshes, Polygonal Meshes, and Subdivision Surfaces.
NURBS modelling includes approximating and interpolating curves as well as extrude, revolve, sweep, birail, skin, and gordon objects with caps, holes, and bevels.
First modelling environment to support Subdivision NURBS.
Custom objects that may freely implement their representations (using OpenGL and RIB) and even small GUIs to edit their type specific parameters may be written by the user and dynamically loaded at runtime.
Scripting interfaces: Tcl, JavaScript, Lua; Script objects.
Misc: instancing, arbitrary number of modeling views, object clipboard, independent property clipboard, console, n-level undo.
File formats (r/w): RIB, DXF, 3DM, 3DMF, OBJ, X3D.
Docs: https://ayam.sourceforge.net/docs/ayam.html
INFINIGEN
Infinigen is a procedural generator of 3D scenes, developed by Princeton Vision & Learning Lab. Infinigen is optimized for computer vision research and generates diverse high-quality 3D training data. Infinigen is based on Blender and is free and open-source (BSD 3-Clause License).
BSD 3-Clause License https://infinigen.org/
Acoustic Simulators...
Code_TYMPAN
Code_TYMPAN™ is an open source software for calculating industrial noise in the environment. It allows dealing with 3D realistic geometries and has a convenient Human Machine Interface to help engineers to build 3D models and to achieve analysis needed in environmental noise studies.
GNU General Public License version 3.0 (GPLv3) https://sourceforge.net/projects/code-tympan/
AVRS
AVRS performs spatial 3D-sound processing allowing the arbitrary placement of sound source in auditory space.
GNU General Public License version 3.0 (GPLv3) https://sourceforge.net/projects/avrsystem/
Comments
CFAST, MAYO, LEKAN, DESIGN added to Software directory wiki.
Open-Infra-Platform
https://github.com/tumcms/Open-Infra-Platform
IFC viewer.
GPL-V3
Blender Earth Modeler Add-on | 3D Google Earth (City/Terrain) inside Blender

Graphite is an in-development raster and vector graphics package that's free and open source. It is powered by a node graph compositing engine that fuses layers with nodes, providing a fully nondestructive editing experience.
https://graphite.rs/
OSAFE Workbench (FreeCAD addon)
https://github.com/ebrahimraeyat/OSAFE
The OSAFE workbench by Ebrahim Raeyat. This FreeCAD Addon is a collection of civil engineering tools, originally designed as a workaround for issues with CSI SAFE. The addon is available via the regular Addon Manager.
GPL-V3
SOLARIUM
https://github.com/elschilling/solarium
Open Source software to host and share sun path visualizations.
https://wvsolarium.vercel.app/
GPL-V3
Just reviewing this thread regarding OS and Free software. Although not specifically AEC software but for myself and others that plan to record video tutorials and post edit, Blackmagic offers a world class video editing application called Davinci Resolve. Fantastic application and very open community.
FloorPagingTool: Tool for creating floors and coverings to complement FreeCAD's WB BIM

License: unknown
https://github.com/maykowsm/FloorPagingTool
Free and open source NURBS Modeller.

License: BSD
https://ayam.sourceforge.net/
Ayam is a free 3D modelling environment for the RenderMan interface, distributed under the BSD licence.
The current stable version is 1.33, released 25. Jul 2023.
Ayam currently runs on Unix (Linux, IRIX, FreeBSD tested), Win32 (Win95-Win2000, XP, 7), and Mac OS X (Aqua and X11).
Ayam features at a glance:
RIB (RenderMan Interface Bytestream) export and import.
Support for NURBS curves and (trimmed) NURBS surfaces, Boxes, Quadrics (Sphere, Disk, Cylinder, Cone, Hyperboloid, Paraboloid, and Torus), CSG, MetaBalls, Patch Meshes, Polygonal Meshes, and Subdivision Surfaces.
NURBS modelling includes approximating and interpolating curves as well as extrude, revolve, sweep, birail, skin, and gordon objects with caps, holes, and bevels.
First modelling environment to support Subdivision NURBS.
Custom objects that may freely implement their representations (using OpenGL and RIB) and even small GUIs to edit their type specific parameters may be written by the user and dynamically loaded at runtime.
Scripting interfaces: Tcl, JavaScript, Lua; Script objects.
Misc: instancing, arbitrary number of modeling views, object clipboard, independent property clipboard, console, n-level undo.
File formats (r/w): RIB, DXF, 3DM, 3DMF, OBJ, X3D.
Docs: https://ayam.sourceforge.net/docs/ayam.html
GISWATER
https://www.giswater.org/
Giswater software focused to management of water cycle using open source tools
GPL-V3
Blender CAM : https://github.com/blendercam/blendercam
Blender CAM is an open source solution for artistic CAM - Computer aided machining - g-code generation tool.
GPL-2
Added to the wiki list: BlenderCAM, Graphite, Open-Infra-Platform, Solarium, OSAFE, GISWATER
Also deleting spam links
Everything U.S. taxes pay for. https://code.gov/
My personal favorite. https://www.rmc.usace.army.mil/Software/LifeSim/
Interesting. We have this list of agent-based system software https://wiki.osarch.org/index.php?title=AEC_Free_Software_directory#Traffic_and_pedestrian_analysis.2Fsimulation
OpenBuilding tools
Online Energy modelling tools for regulations: Carbon Calculator, TEUI Calculator, TEDI Calculator, Affordability Pie.
Free.
https://openbuilding.ca/tools/carbon-calculator/
https://openbuilding.ca/tools/teui-calculator/
https://openbuilding.ca/tools/ventilation-calculator/
https://openbuilding.ca/tools/affordability-pie/
INFINIGEN
Infinigen is a procedural generator of 3D scenes, developed by Princeton Vision & Learning Lab. Infinigen is optimized for computer vision research and generates diverse high-quality 3D training data. Infinigen is based on Blender and is free and open-source (BSD 3-Clause License).
BSD 3-Clause License
https://infinigen.org/
https://openswmm.org/- storm water management modelling software
https://github.com/TchilDill/openpile - Pile Calculation
Acoustic Simulators...
Code_TYMPAN
Code_TYMPAN™ is an open source software for calculating industrial noise in the environment. It allows dealing with 3D realistic geometries and has a convenient Human Machine Interface to help engineers to build 3D models and to achieve analysis needed in environmental noise studies.
GNU General Public License version 3.0 (GPLv3)
https://sourceforge.net/projects/code-tympan/
AVRS
AVRS performs spatial 3D-sound processing allowing the arbitrary placement of sound source in auditory space.
GNU General Public License version 3.0 (GPLv3)
https://sourceforge.net/projects/avrsystem/