With deferred shading you can place dynamic particle lights into the world using Cascade. You can also soften the overall look of a sprite based on the velocity at which the sprite is moving. These expressions give artists a more refined level of control over a sprite for instance, you can sample the particle velocity, return a velocity value, and modify material parameters in real time based on the velocity of a sprite. There are several new material expressions in UE4 that are custom to particle systems. Lit effects can also cast shadows onto themselves and into the environment. In UE4 effects with lit translucency accept lighting and shadow information. Depth buffer particles also obey masked surface properties, so any grates, holes, or other surfaces created with masked gaps in them will allow sprites using depth collision to fall through those gaps. The system makes use of depth buffer information, as well as surface normal information to simulate particle motion. In UE4 effects artists can emit large amounts of meshes into the scene at standard CPU simulation costs with no additional draw call overhead.Д¬urrently enabled for GPU simulations, depth buffer collision is an efficient means of doing high-detail collision, with large amounts of particles at a low evaluation cost. Low fixed-cost mesh emission is now a single draw call per emitter, depending upon the material, instead of a draw call per mesh. Vector fields can be manipulated within Cascade to add additional motion to any GPU simulation. Vector field grids enable artists to create dynamic, organic movement within a GPU particle system. These new GPU particles provide the backbone for several new features in UE4. UE4 still makes use of CascadeвЂ™s CPU simulations, which can be leveraged to control the behavior of GPU systems.

GPU particle simulation makes it possible to simulate millions of particles in a scene with minimal evaluation cost. Unreal Cascade is the Unreal EngineвЂ™s built-in visual effects editor. Tim Elek: UE4 has many new effects features which complement the Cascade workflow. fxguide spoke to Epic Games senior FX artist Tim Elek about UE4вЂ™s capabilities and how they were put to use in вЂInfiltratorвЂ™.ДЇxg: Can you talk about some of the new features in UE4 that are specifically designed for effects work? Part of UE4вЂ™s advanced tech is its improved effects tools using GPU particle sims, collisions and dynamic particle lights. Earlier this year at GDC, Epic Games showcased the new Unreal Engine 4 via a real-time demo video called вЂInfiltratorвЂ™.

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