Applying new approaches, methods, and technologies for the estimation of reserves can effectively improve the efficiency and accuracy of assessments of solid mineral resources. After analyzing the development of 3-D g...Applying new approaches, methods, and technologies for the estimation of reserves can effectively improve the efficiency and accuracy of assessments of solid mineral resources. After analyzing the development of 3-D geoscience modeling technology （3-D GMT）, this paper discusses the application of 3-D GMT for the estimation of solid mineral reserves, emphatically introducing its workflow and two key technologies, 3-D orebody surface modeling, and property modeling. Moreover, the paper analyzes the limitations of traditional methods, such as the section method and geological block method, and points out the advantages of 3-D GMT： building more accurate 3-D orebody models, expressing the internal inhomogeneous attributes of an orebody, reducing the potential for errors in the estimation of reserves, and implementing dynamic estimations of reserves.展开更多
Intersecting is an important factor which influences the effociency androbustness of Boolean algorithms in solid modeling based on surved-surfaces,andintersecting algorithms are closely related to geometric representa...Intersecting is an important factor which influences the effociency androbustness of Boolean algorithms in solid modeling based on surved-surfaces,andintersecting algorithms are closely related to geometric representations of curved-surfaces.Although surfaces can be commonly represented with NURBS,unnecessary complexitiesare caused in the intersecting of quadric surfaces.Quadrics are frequently used to des-cribe geometric features of shafts,holes and grooves etc.in mechanical part designing,therefore;their intersection algorithms are required to have higher accuracy,higher efficiency and higher robustness.For this reason,a practical representation ofquadric surfaces is studied in detail,and on the basis of that,algorithms of intersectingpoints are developed between quadric suraces and their boundaies,i.e.,conics,quarticnonplanar space curves.展开更多
In the previous work, an efficient method has been proposed to represent solid objects as multiple combinations of globally deformed supershapes. In this paper, this framework is applied with a new supershape implicit...In the previous work, an efficient method has been proposed to represent solid objects as multiple combinations of globally deformed supershapes. In this paper, this framework is applied with a new supershape implicit function that is based on the notion of radial distance and results are presented on realistic models composed of hundreds of hierarchically globally deformed supershapes. An implicit equation with guaranteed differential properties is obtained by simple combinations of the primitives~ implicit representations using R-function theory. The surface corresponding to the zero-set of the implicit equation is efficiently and directly polygonized using the primitives,parametric forms. Moreover, hierarchical global deformations are considered to increase the range of shapes that can be modeled. The potential of the approach is illustrated by representing complex models composed of several hundreds of primitives inspired from CAD models of mechanical parts.展开更多
Parametric surfacelsurface intersection methods are essential in a sculptured solid modelingsystem- To improve the robustness, accuracy and topological consistence, an algorithm extendedfrom ideas in [1] and in [3] is...Parametric surfacelsurface intersection methods are essential in a sculptured solid modelingsystem- To improve the robustness, accuracy and topological consistence, an algorithm extendedfrom ideas in [1] and in [3] is described in this paper. Including a new rnethod for obtaining the sur-face near points; an appropriate method for estimating the marching step length; and a reliablernethod for determining singular points. Furthermore, our algorithm can evaluate intersections between offset surfaces without offset approximation. These ideas are discussed and implemented in anintegrated CADICAM system. Tested by rnany typical examples , they have been proved to be robustand efficient. Some exarnples are provided.展开更多
文摘Applying new approaches, methods, and technologies for the estimation of reserves can effectively improve the efficiency and accuracy of assessments of solid mineral resources. After analyzing the development of 3-D geoscience modeling technology （3-D GMT）, this paper discusses the application of 3-D GMT for the estimation of solid mineral reserves, emphatically introducing its workflow and two key technologies, 3-D orebody surface modeling, and property modeling. Moreover, the paper analyzes the limitations of traditional methods, such as the section method and geological block method, and points out the advantages of 3-D GMT： building more accurate 3-D orebody models, expressing the internal inhomogeneous attributes of an orebody, reducing the potential for errors in the estimation of reserves, and implementing dynamic estimations of reserves.
文摘Intersecting is an important factor which influences the effociency androbustness of Boolean algorithms in solid modeling based on surved-surfaces,andintersecting algorithms are closely related to geometric representations of curved-surfaces.Although surfaces can be commonly represented with NURBS,unnecessary complexitiesare caused in the intersecting of quadric surfaces.Quadrics are frequently used to des-cribe geometric features of shafts,holes and grooves etc.in mechanical part designing,therefore;their intersection algorithms are required to have higher accuracy,higher efficiency and higher robustness.For this reason,a practical representation ofquadric surfaces is studied in detail,and on the basis of that,algorithms of intersectingpoints are developed between quadric suraces and their boundaies,i.e.,conics,quarticnonplanar space curves.
文摘In the previous work, an efficient method has been proposed to represent solid objects as multiple combinations of globally deformed supershapes. In this paper, this framework is applied with a new supershape implicit function that is based on the notion of radial distance and results are presented on realistic models composed of hundreds of hierarchically globally deformed supershapes. An implicit equation with guaranteed differential properties is obtained by simple combinations of the primitives~ implicit representations using R-function theory. The surface corresponding to the zero-set of the implicit equation is efficiently and directly polygonized using the primitives,parametric forms. Moreover, hierarchical global deformations are considered to increase the range of shapes that can be modeled. The potential of the approach is illustrated by representing complex models composed of several hundreds of primitives inspired from CAD models of mechanical parts.
文摘Parametric surfacelsurface intersection methods are essential in a sculptured solid modelingsystem- To improve the robustness, accuracy and topological consistence, an algorithm extendedfrom ideas in [1] and in [3] is described in this paper. Including a new rnethod for obtaining the sur-face near points; an appropriate method for estimating the marching step length; and a reliablernethod for determining singular points. Furthermore, our algorithm can evaluate intersections between offset surfaces without offset approximation. These ideas are discussed and implemented in anintegrated CADICAM system. Tested by rnany typical examples , they have been proved to be robustand efficient. Some exarnples are provided.
