ABSTRACT
This chapter will expand our knowledge of paths and help us learn what various options are available. When objects reach the end of a path, they will do one of several things:
• Remain there until some later time • Be destroyed (taken out of the animation) • Be placed on another path • MOVE to a point
In actual simulations, we know that objects may reach a certain point and wait there for a time before they move to another path. This might be the case for cars coming to a stoplight that is red. Trucks arriving at a shovel to be loaded when another truck is being loaded is another example. PROOF handles this situation by a two-part operation. First, it gives the various CLASSes clearances that can be in front of the object ( fore clearance) and/or at the back of the object (aft clearance). These clearances are distances whereby another object cannot impinge on it. Both of these clearances are positive numbers. For example, a CLASS may be 1 unit in length with the hot point in the middle (.50 unit from the front and back). If there is no clearance, another object from this CLASS will totally override it if both come to the end of the same path and you will see only the second object. If the
fore clearance is .50 unit and the aft clearance is also .50 unit, a second object will come to rest exactly at the back of the first object. This will become clear by running the animation CHAP4A. A screenshot when the animation is finished is given in Figure 4.1.
