When creating a physics system in GameMaker Studio 2, it is often important to have a visual representation of what is actually happening with an instance. This can be achieved by using physics_draw_debug, which draws a schematic outline of the physical properties associated with the instance running the code. Here is an image of how it looks:
It should be noted that for this to work it must be in the draw event of the instance, and it will be drawn using the currently defined draw colour.
The code above will draw a representation of the physical properties associated with that instance using the colour red.