A method of processing obj files based on vtk

Abstract

The invention discloses a method for processing an obj file on the basis of a vtk (Visualization Toolkit). The method comprises the following steps that: S1: reading a surface patch in an obj file, and constructing a reverse index table; S2: searching a shared vertex; S3: generating a new vertex, updating and constructing surface patch id (Identification) if the shared vertex is found, if no shared vertexes are found, generating a new vertex which has the same position, and jumping to S4; S4: increasing the surface patch, generating the new vertex, adding the surface patch for connecting the new vertex with the old vertex for continuity between the new vertex and the old vertex, and adding the new vertex into a vertex set; S5: subsequent vertexes and subsequent surface patches: if the subsequent vertex of the surface patch is not processed, jumping to S2, and if the subsequent surface patch of the model is not processed, jumping to S1; S6: triangular surface patch processing: splitting all surface patches into triangular surface patches; and S7: hook face smoothness: applying a loop hook surface subdivision algorithm to smoothen the model.

Description

technical field [0001] The invention belongs to the field of computer graphics, in particular to a method for processing obj files based on vtk. Background technique [0002] A 3D model is a polygonal representation of an object, usually displayed on a computer or other video device. Objects shown may be real-world entities or fictional objects. Anything that exists in physical nature can be represented by a three-dimensional model. [0003] For objects with smooth expressions, the more polygons are needed, if the number is insufficient, the 3D model constructed and processed will not be smooth enough. At this time, it is necessary to apply the surface subdivision algorithm to automatically increase the number of polygons to make the model smooth. However, the input surface required by the surface subdivision algorithm is continuous, and the direct application of the subdivision algorithm to the surface constructed by discrete patches will produce many holes. For polygona...

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Problems solved by technology

[0003] For objects with smooth expressions, the more polygons are needed, if the number is insufficient, the 3D model constructed and processed will not be smooth enough. At this time, it is necessary to apply the surface subdivision algorithm to automatically increase the number of polygons to make the model smooth. However, the input surface required by the surface subdivision algorithm is continuous, and the direct application of the subdivision algorithm to the surface constructed by discrete patches will produce many holes.

For polygonal vertices, there may be multiple texture coordinates, but in vtk (visualization tool library, Visualization Toolkit), a vertex id (identity card, identification) can only correspond to one texture coordinate id, which makes One vertex is not enough, you need to add a new position

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