Fluid animation can be performed with different levels of complexity, ranging from time-consuming, high-quality animations for films or visual effects, to simple and fast animations for real-time animations like computer games. However, some fluid animation techniques trace their origins to the computational fluid dynamics community. 3D Navier-Stokes equations in a computer graphics context, basing their work on a scientific CFD paper by Harlow and Welch from 1965. Fluid simulation for computer graphics bridson pdf allowed for much larger time steps and therefore faster simulations.
Many 3D computer graphics programs implement fluid animation techniques. 3D computer graphics programs that enable fluid animation. This page was last edited on 5 December 2017, at 00:28. The applications are mostly in video games and films. The scope of soft body dynamics is quite broad, including simulation of soft organic materials such as muscle, fat, hair and vegetation, as well as other deformable materials such as clothing and fabric. Softbody objects react to forces and are able to collide with other 3D objects.
Two nodes as mass points connected by a parallel circuit of a spring and a damper. Additional springs between nodes can be added, or the force law of the springs modified, to achieve desired effects. To approximate finite element simulation, shape matching can be applied to three dimensional lattices and multiple shape matching constraints blended. It can also be used to simulate two dimensional sheets of materials other than textiles, such as deformable metal panels or vegetation. The mass-spring model is converted into a system of constraints, which demands that the distance between the connected nodes be equal to the initial distance. This system is solved sequentially and iteratively, by directly moving nodes to satisfy each constraint, until sufficiently stiff cloth is obtained. Realistic interaction of simulated soft objects with their environment may be important for obtaining visually realistic results.
Cloth self-intersection is important in some applications for acceptably realistic simulated garments. This is challenging to achieve at interactive frame rates, particularly in the case of detecting and resolving self collisions and mutual collisions between two or more deformable objects. Detection of collisions between cloth and environmental objects with a well defined “inside” is straightforward since the system can detect unambiguously whether the cloth mesh vertices and faces are intersecting the body and resolve them accordingly. Mutual- or self-collisions of soft bodies defined by tetrahedra is straightforward, since it reduces to detection of collisions between solid tetrahedra.
Solutions involve either using the history of the cloth motion to determine if an intersection event has occurred, or doing a global analysis of the cloth state to detect and resolve self-intersections. Currently, this is generally too computationally expensive for real-time cloth systems. To do collision detection efficiently, primitives which are certainly not colliding must be identified as soon as possible and discarded from consideration to avoid wasting time. Hybrid methods involving a combination of various of these schemes, e. AABB tree plus sweep-and-prune with coherence between colliding leaves.