摘要:
The described systems and methods are directed at interactively rendering graphics using precomputed radiance transfer (PRT). A reflectance matrix that represents the reflectance of a particular object to be rendered is determined. Source lighting associated with the object is represented using basis functions. The reflectance matrix is factored into view and light components. A raw transfer matrix is determined based, in part, from the factored reflectance matrix and the source lighting. The raw transfer matrix is partitioned to obtain transfer matrices, which are used to render the object. The described systems and methods are capable of rendering glossy objects with well-defined shadows.
摘要:
Computer graphics image rendering techniques render images modeling transfer at two scales. A macro-scale is coarsely sampled over an object's surface, providing global effects like shadows and interreflections cast from an arm onto a body. A meso-scale is finely sampled over a small patch to provide local texture. Low-order spherical harmonics represent low-frequency lighting dependence for both scales. To render, a coefficient vector representing distant source lighting is first transformed at the macro-scale by a matrix at each vertex of a coarse mesh, resulting in vectors representing a spatially-varying hemisphere of lighting incident to the meso-scale. A radiance transfer texture specifies the meso-scale response to each lighting basis component, and a function of a spatial index and a view direction. A dot product of the macro-scale result vector with the vector looked up from the radiance transfer texture performs the correct shading integral. An id map places radiance transfer texture samples from a small patch over the object's surface, so that only two scalars are specified at high spatial resolution.
摘要:
Large mesh deformation using the volumetric graph Laplacian is described. In one aspect, information is received from a user, wherein the information indicates how an original mesh is to be deformed. The original mesh is then deformed based on the information and application of a volumetric differential operator to a volumetric graph generated from the original mesh.
摘要:
Large mesh deformation using the volumetric graph Laplacian is described. In one aspect, information is received from a user, wherein the information indicates how an original mesh is to be deformed. The original mesh is then deformed based on the information and application of a volumetric differential operator to a volumetric graph generated from the original mesh.
摘要:
A computer implemented method for deforming a 3D polygon mesh using non-linear and linear constraints. The method includes creating a coarse control 3D polygon mesh that completely encapsulates the 3D polygon mesh to be deformed, projecting the deformation energy of the 3D polygon mesh and the constraints of the 3D polygon mesh to the vertices, or subspace, of the coarse control 3D polygon mesh, and determining the resulting deformed 3D polygon mesh by iteratively determining the deformation energy of the subspace. The constraints may be either linear or non-linear constraints, for example, a Laplacian constraint, a position constraint, a projection constraint, a skeleton constraint, or a volume constraint.
摘要:
A system and process for determining the similarity in the shape of objects is presented that generates a novel shape representation called a directional histogram model. This shape representative captures the shape variations of an object with viewing direction, using thickness histograms. The resulting directional histogram model is substantially invariant to scaling and translation. A matrix descriptor can also be derived by applying the spherical harmonic transform to the directional histogram model. The resulting matrix descriptor is substantially invariant to not only scaling and translation, but rotation as well. The matrix descriptor is also robust with respect to local modification or noise, and able to readily distinguish objects with different global shapes. The typical applications of the directional histogram model and matrix descriptor include recognizing 3D solid shapes, measuring the similarity between different objects and shape similarity based object retrieval.
摘要:
A computer implemented method for deforming a 3D polygon mesh using non-linear and linear constraints. The method includes creating a coarse control 3D polygon mesh that completely encapsulates the 3D polygon mesh to be deformed, projecting the deformation energy of the 3D polygon mesh and the constraints of the 3D polygon mesh to the vertices, or subspace, of the coarse control 3D polygon mesh, and determining the resulting deformed 3D polygon mesh by iteratively determining the deformation energy of the subspace. The constraints may be either linear or non-linear constraints, for example, a Laplacian constraint, a position constraint, a projection constraint, a skeleton constraint, or a volume constraint.
摘要:
The described systems and methods are directed at interactively rendering graphics using precomputed radiance transfer (PRT). A reflectance matrix that represents the reflectance of a particular object to be rendered is determined. Source lighting associated with the object is represented using basis functions. The reflectance matrix is factored into view and light components. A raw transfer matrix is determined based, in part, from the factored reflectance matrix and the source lighting. The raw transfer matrix is partitioned to obtain transfer matrices, which are used to render the object. The described systems and methods are capable of rendering glossy objects with well-defined shadows.
摘要:
A method and system for implementing capturing and rendering geometric details for mesostructure surfaces is described herein. A mesostructure distance function is defined as a function of a given reference point and a given viewing direction. A distance from a reference point to a mesostructure surface point along a viewing direction is measured using the mesostructure distance function. This distance is used to determine the visibility of mesostructure surface for rendering silhouettes. The lighting visibility of the mesostructure surface point may also be determined and used for determining whether the mesostructure surface point is in shadow. This determination may then be used for rendering shadow silhouettes.
摘要:
A method for creating an optimized gradient mesh of a vector-based image from a raster-based image. In one implementation, a set of boundaries for an object on a raster-based image may be received. An initial gradient mesh of the object may be created. A residual energy between the object on the raster-based image and a rendered initial gradient mesh may be minimized to generate an optimized gradient mesh.