What controls which units appear in a build menu, how to get Blender models into BAR with proper texturing, and common hurdles when working with custom content.
Every BAR building has a buildoptions table in its unit definition file. That table determines which units show up when you click on a factory or constructor. The Arm vehicle plant at units/ArmBuildings/LandFactories/armvp.lua line 37 is a real example in the repo.
If you are modding and a unit is not appearing where you expect, the buildoptions table is the first place to check. It is not a separate file or hidden config. It is right there in the unit def, and adding an entry means adding the unit name to that table.
The SpringRTS export workflow gets a model file into the game, but BAR handles texturing differently. The engine uses three megatextures, and that is where most exporters get stuck. The model loads into the game without error, but textures do not render correctly.
The practical path is to study existing unit files in the repo and match their texture pipeline. BAR stores texture references and megatexture assignments in the unit definition alongside the model path. Do not try to guess the format. Copy the structure from a working unit that uses a similar material type and adjust the texture path.
Modders working on the Whistler and Commander Slasher variants shared visual tweaks through the modding channels. These are purely aesthetic changes and need artists, not programmers. If you improve unit visuals, post your work where the community collects and reviews modding contributions.
Some modders want to track which map areas have the most projectile activity, typically for spectator overlays or replay analysis tools. The challenge is that projectile tracking requires hooking into the engine per frame and aggregating positions. The concept works but the implementation is computationally expensive.
The pattern for every BAR modding question is the same. Look at the repo. Find the unit file that does something similar. Copy the structure. Change the values. The community accepts good attempts and helps fix small mistakes.
"One of the few places where you can for sure coordinate with people in matches with a good supportive attitude. Everybody tends to be understanding and constructive."