functionality for expert users, but requires somewhat more work by the user. Materials created using the standard material attributes can be converted to custom shaders to serve as a starting point in the Shader Editor. The terrain capabilities of the C4 Engine are based on a voxel technology, allowing full 3D sculpting to produce features such as overhangs, arches, and truly vertical cliffs that would not be possible under a conventional height-based terrain system. Triangle meshes are generated from voxel data using the Marching cubes algorithm, and seamless multiresolution level of detail is made possible by using the Transvoxel algorithm to stitch together regions of differing resolutions. The engine is capable of rendering a large variety of special effects, including particle systems, procedural fire, electrical effects, volumetric fog, and weather phenomena. During a post-processing stage, the engine can also apply full-scene cinematic motion blur to the final image using a technique based on a velocity buffer, as well as glow and distortion effects. The engine does not provide the capability to design custom post-processing effects. Audio The C4 Engine can play sounds stored in the WAV format using 16-bit mono or stereo sampling, and audio data can be played from memory or streamed from disk. The engine plays sounds using a custom mixer that provides capabilities such as frequency shifting, Doppler effect, reverberation, and atmospheric absorption. Networking Multiplayer gameplay in C4 is supported by a two-layer messaging system that uses the User Datagram Protocol to communicate among different computers connected to a game. Physics The C4 Engine has a native physics engine which can be used or allows the option for implementing a 3rd party solution instead. Tools The C4 Engine ships with basic game development tools required to make a modern game. Each tool is packaged as a plugin module that exists separately from the engine itself. Many tools make use of the comprehensive graphical user interface system provided by the engine so that a consistent interface is presented to the user across multiple platforms. World Editor The World Editor tool is a 3D content creation application that is typically used to create game environments for use with the C4 Engine. It provides a large set of drawing and manipulation capabilities that are used to construct world geometry as well as many game necessities such as lights, sounds, triggers, and special effects. The World Editor can import scene information