5 results about "Quadratic error" patented technology

The invention discloses a lightweight method and system for a highway engineering three-dimensional live-action model and a medium, and relates to the technical field of three-dimensional live-action modeling. The method comprises the following steps: firstly, carrying out engineering semantic segmentation on an input three-dimensional grid model, and extracting design parameters in a BIM / GIS (Basic Information Model / Geographic Information System); then, constructing a multi-level constraint model fusing semantic constraints, engineering precision constraints and design parameter constraints; and finally, carrying out iterative simplification under the guidance and limitation of the multi-level constraint model by adopting an improved quadratic error measurement algorithm. The method solves the problems of semantic information loss, out-of-control local precision and disjunction with design intention when a traditional pure geometric simplification method is applied to highway engineering, and can intelligently reserve key engineering characteristics, control geometric errors and fit a design form while ensuring that the data size of the model is greatly reduced. And a high-quality lightweight model suitable for professional analysis and application is generated.

The invention relates to the technical field of three-dimensional modeling, in particular to a building outer surface model rapid construction method based on a BIM technology, and is used for solving the technical problem of insufficient model precision of BIM modeling in the prior art. The method comprises the following steps: constructing a first triangular mesh model based on building outer surface data; calculating a first folding cost of each edge of each triangle in the first triangular mesh model based on a quadratic error measurement method; correcting the first folding cost of each edge based on the first inhibition factor of each edge and / or the second inhibition factor of each edge to obtain the second folding cost of each edge; the first inhibition factor is used for inhibiting the folding cost of a high-detail-density region, and the second inhibition factor is used for inhibiting the folding cost of a high-shape-change region; and simplifying the edges in the first triangular mesh model based on the second folding cost of each edge to obtain a second triangular mesh model.

The application provides a three-dimensional mesh model simplification method, device, equipment and medium, and relates to the technical field of model simplification. The method comprises the following steps: adopting a region growing algorithm, determining a growing region according to a free selection region and geometric topology information of a three-dimensional mesh model; determining an error matrix of each triangular facet in the growing region according to the geometric topology information, and determining the sum of quadratic errors of all associated triangular facets according to the error matrix; determining a vertex folding cost and a new vertex according to the sum of quadratic errors, determining an edge folding cost and performing priority sorting according to the new vertex; and performing edge simplification folding according to the sorted edge folding cost, so as to obtain simplified vertices and corresponding simplified geometric topology information. The application can improve the simplification effect.

The application relates to the technical field of three-dimensional modeling, in particular to a building outer surface model rapid construction method based on BIM technology, which is used to solve the technical problem of insufficient model precision in BIM modeling in the prior art. The method comprises the following steps: constructing a first triangular mesh model based on building outer surface data; calculating a first folding cost of each edge of each triangle in the first triangular mesh model based on a quadratic error measurement method; correcting the first folding cost of each edge based on a first inhibition factor of each edge and / or a second inhibition factor of each edge to obtain a second folding cost of each edge; the first inhibition factor is used to inhibit the folding cost of a high-detail-density area, and the second inhibition factor is used to inhibit the folding cost of a high-shape-change area; and performing simplification processing on the edges in the first triangular mesh model based on the second folding cost of each edge to obtain a second triangular mesh model.

The application discloses a triangle mesh graph neural network simplification method, and belongs to the technical field of computer deep learning, which acquires a triangle mesh model to be simplified and constructs a graph structure with vertices as nodes and undirected edges based on the topological relation of triangular facets as graph edges; the nodes are subjected to feature initialization, and geometric, topological and Laplacian position coding information is fused; a multi-scale adjacency relation containing 1st-order adjacent edges and 2nd-order adjacent edges is constructed; the node features and the multi-scale adjacency relation are input into a graph neural network, message passing and feature aggregation are completed in different neighborhoods based on a graph convolution network, and edge importance probability is predicted; the edge geometric structure importance is integrated into a simplification process, and the key feature protection effect is improved; the geometric structure features extracted by deep learning are combined with a classical quadratic error measurement algorithm, and the edge collapse cost is dynamically scaled, so that the number of mesh facets is greatly reduced, and the geometric features and the topological structure of the model are effectively maintained.