Abstract: Animation controls according to the present invention introduce a predictable level of control for animation without the need for iterating the simulation. Controls include shape controls that permit the effect of the simulation to be overridden for cloth and soft body materials. The effect of shape tacks are to control the local shape of objects such as cloth and soft body materials, the shape may be weighted and time varying. Shape tacking is relative to the reference coordinate system of the object being shaped. Position tacks provide control in absolute space and permit accurate placement of an object to be animated overriding the control of the simulation.

Abstract: The present invention presents techniques for simulating and generating lifelike digital representations of scenes that may include one or more dynamic linear objects such as rope, antennae, hair, feathers, fur and grasses. Individualized geometric models may be defined for a selected, manageable subset of the linear objects. By interpolating and animating based upon these defined geometric models, subject to user-specified object parameters, a dynamic simulation and a static geometry may subsequently be generated. Rendering techniques according to the present invention may be used to generate two-dimensional image projections of these geometries, as seen from a specified point of view. These steps of geometric interpolation and rendering are performed in an iterative manner, such that numerous fine-grained objects may be processed and rendered portion by portion, thereby greatly reducing the computational complexity of the task.

Abstract: A dynamic cloth simulation technique according to the present invention decomposes the second order differential equations of motion into two first order differential equations which permits separation of position and velocity terms. In another aspect of the present invention tensile stiffness terms are separated from bending and damping terms. The bending and damping terms may be integrated using long time steps to promote simulation stability. Tensile stiffness terms may be calculated in sub-cycle periods shorter than the long time steps used for bending and damping calculations. Use of short sub-cycle steps in simulations of garments having high tensile spring forces permits a stable dynamic simulation with a high degreee of realism.

Abstract: The present invention provides methods and apparatus for creating lifelike digital representations of three-dimensional objects. Steps and means are described by which an animator may efficiently select and combine a plurality of animated objects to generate a new animated objects. According to the present invention, an animator may store a plurality of object shapes. To minimize storage, all of the object shapes are stored solely as differences from a base object. To form a new object, an animator may select from the database a number of objects with the desired characteristics and these objects will be blended with one another to create a new object with features that are a combination of the selected objects. The extent to which a selected object is incorporated into the new object may be selected by the animator by assigning each selected object with a weight.