CollideFx is a real-time audio effects processor that integrates the physics of real objects into the parameter space of the signal chain. Much like a traditional signal chain, the user can choose a series of effects and offer realtime control to their various parameters. In this work, we introduce a means of creating tree-like signal graphs that dynamically change their routing in response to changes in the location of the unit generators in a virtual space. Signals are rerouted using a crossfading scheme that avoids the harsh clicks and pops associated with amplitude discontinuities. The unit generators are easily controllable using a click and drag interface that responds using familiar physics. CollideFx brings the interactivity of a video game together with the purpose of creating interesting and complex audio effects. With little difficulty, users can craft custom effects, or alternatively, can fling a unit generator into a cluster of several others to obtain more surprising results, letting the physics engine do the decision making.