Heavy objects being managed by the STK Object Model Broker will always use the real-time propagator for their tracks and cannot be modified to use any other; all other attributes of an object can be customized to your liking. Much like STK, when a new object is created by the STK Object Model Broker it loads a default object from disk. Also like STK, you can create your own default objects for the STK Object Model Broker to use. The initial default files can be found on your computer in the STKData\Defaults directory in your STK install directory. You will see a _BrokerDefault object for each STK object type; for example, the default Aircraft object is _BrokerDefault.ac. It is important to note that this default is different than the standard STK _Default object, and using the “Set as Default” option in STK will have no affect on the STK Object Model Broker. To make your own defaults:
After this is completed, whenever the STK Object Model Broker needs to create an object of that type, it will load your newly defined default object instead. This is very useful for tweaking low-level STK settings of individual objects.
STK 11.2.1 Programming Interface