Nice buildings and simulations, you must have been quite busy making them.
For the Detonator functionality you just need an empty object with the name defined as in the BCB settings in your scene. Scale it to the size of the area you want to weaken and place it where it should act at the building. Leave the Advanced Detonator unchecked to have a basic gradient-like weakening from the beginning.
If you want to use Advanced Detonator you need to simulate the entire propagation of the pressure wave in advance which makes it a bit more complex to control. I have committed another example file for this new feature to the repo:
The gaps are the result of the Rescale Factor setting which is 0.95 by default. It is useful to have these gaps for simulation to avoid intersections on deforming structures. I usually leave them in for simulation and revert them afterwards using a trick with a negative smooth modifier, but this only works well for clean box-like elements. Of course you can also change the Rescale Factor to 1.0 if accuracy is of less importance to you.
Progressive Weakening is another trigger feature independent from the Detonator, but this only works if no FM is used. It will weaken the entire structure with a defined factor per frame until collapse begins. You can try it with a value of 0.98 or so, after a while of weakening the structure will start to fail at their weakest points.
I’m using OpenGL viewport rendering for most of my simulations because it saves a lot of time, with some experience you can accomplish quite nice images even with old-school methods.
I will share a video of yours in my community tab if you don’t mind. Keep it up.