|导师||张晓鹏 ; 叶军涛|
|关键词||过度拉伸 各项异性 应变极限 不等式优化 离散碰撞检测 服装建模 穿透修复 交互式服装设计|
An anisotropic strain-limiting algorithm with inequality constraints along the warp and weft directions. The cloth simulation systems often suffer from excessive extension on the polygonal mesh, so an additional strain-limiting process is typically used as a remedy in the simulation pipeline. A cloth model can be discretize as either a quadrilateral mesh or a triangular mesh, and their strains are measured differently. For a triangular mesh, the state-of-the-art technique measures and constrains the strains along the two principal directions in a trianglue, resulting in an isotropic behavior which prohibits shearing. Based on the framework of inequality-constrained optimization, we proposed a warp and weft strain-limiting formulation. This anisotropic model is more appropriate for textile materials that do not exhibit isotropic strain behavior. The edge-based strain-limiting method for a quadrilateral mesh creates anisotropic behavior by nature, as discretization usually aligns the edges along the warp and weft directions. We improve this anisotropic technique by replacing the traditionally used equality constraints with inequality ones in the mathematical optimization, and achieve faster convergence.
An untangling strategy based on minimum positional displacements, for the intersections of unoriented surfaces. The popular collision response methods rely on continuous collision detection, which is history-based. If the same hard constraint is assumed as in CCD, we found the majority of collisions can be resolved by discrete detection with the help of history information. Instead of detecting all collision events happening during interal, ours MPD detects all edge-face intersections at the end of interval via DCD algorithm, and inters the collisions events that cause the intersections. At the same time, collision normals are determined and stencils are identified. Minimum displacements are computed so that stencil vertices are relocated to a collision-free status. To overcome the excessive elongation due to vertex adjustment, edge strain limits are integrated into the optimization process as constraints, so that the displacement are propagated smoothly.
A framework unified under discrete collision detection, for resolving various types of penetrations within compltex scenes. For the intersections between a soft and solid model, we use the predefined normal of the solid model to decide the illegal vertices and the direction for their movement. For the collision and self-collision between soft models, we use a history-dependent method to form penetration stencils. When neither the predefined normal nor history information exist, we use global intersection analysis to form stencils. The pinching happens when the solid model intersect each other during animation. To get a stable animation, we use a robust skinning-like method to bind the garment vertices on the pinched area of the solid model.
Interactive garment design system. First, we parse DXF file format, which is widely used in the fashion industry, to extract key points on the outline of the panels. Then, we use the key points to form sewing edges. By using our interactive sewing system, we can convert 2D panels to 3D models.
|马光辉. 真实感布料的计算模型及其应用[D]. 北京. 中国科学院研究生院,2017.|