Understanding Line Traces

One of the most important features of any game development tool is its ability to execute Line Traces. These are available through the physics engine that the tool is using.

Line Traces are a way of asking the game to tell you whether anything stands between two points in the game world. The game will shoot a ray between those two points, specified by you, and return the objects that were hit (if any), where they were hit, at what angle, and much more.

In Figure 5.4, you can see a representation of a Line Trace where we assume object 1 is ignored and object 2 is detected,due to their Trace Channel properties (further explained in the following paragraphs):

Figure 5.4 – A Line Trace being executed from point A to point B

Figure 5.4 is explained as follows:

• The dashed line represents the Line Trace before it hits an object.
• The arrows represent the direction of the Line Trace.
• The dotted line represents the...