Currently, all moving geometry is ray traced using a brute force method. Having large quantities of moving geometry will significantly slow ray tracing. In the future, advanced temporal/spatial sorting structures will be used to bypass this limitation, but work on this code addition is not currently in progress.
Since the DIRSIG model now knows the geometry's position as a function of time, the thermal calculations can properly show thermal scarring effects for moving objects. A tank which departed five minutes prior to scene imaging time might, for instance, leave a visible thermal shadow on the asphalt where it was parked for two hours prior.
Using moving geometry also makes it easy to demonstrate effects such as motion blur. In conjunction with the Task Manager functionality of DIRSIG4, it is simple to specify that a scene be captured 3 times per second for a duration of 2 seconds. Using a post-processing tool such as ENVI (with its "Band Math" feature), the generated frames can integrated to demonstrate blurred motion. Note that this was also possible using prior versions of DIRSIG, but would require positioning changes in the ODB for a series of individual runs.