Reassembler v1.4 add "rooted" structure building behavior to the mod. After a lot of experimenting, here are my observations on the subject:

- There are 3 types of blueprint possible in Reassembly: "Ship", "Station" and "Rooted". Ship must consist of a core and a least one thruster. Station must consist of a core without thruster and possibly at least one other part (not tested). Rooted building must consist of a core and one root block with the yellow marked face facing outward in the design. Failure to do this will result in building not spawning as expected on asteroid.

- The mod do not define any pre-made rooted structure. If you don't define any, they will simply not appear.

- If you define at least one rooted blueprint, it may spawn eventually. Exact condition are still a bit unclear but I have seen them appear in several cases in an existing game as well as in a new game.

- You can add shield, factory, weapons and any other block to the design except thrusters as defined above.

Don't forget that the rooted block must have it's yellow face free and facing outward in the design. Left, right, up or down orientation doesn't seem to matter.

Experiment with the rooted designing and have fun!