دانلود رایگان مقاله تجسم GPU خارج از هسته کارآمد مدلهای CAD

Abstract

Visualizing large-scale CAD models has been recognized as one of the most challenging tasks in engineering software development. Due to the constraints of limited GPU memory size and computation capacity, the CAD model of a complex product with hundreds of millions triangles cannot be loaded and rendered in real-time using most of modern GPUs. In this paper, an efficient voxel assisted GPU out-of-core framework is proposed for visualizing massive CAD models interactively. In order to reduce memory cost and improve efficiency of data streaming, a parallel off-line geometry attributes compression scheme is introduced to minimize the storage cost of each primitive by quantifying the LOD (levels of detail) geometries into a highly compact format. At the rendering stage, voxel representation is utilized to query visible objects by efficient ray casting algorithms, which is distinguishable from primitive or bounding box based visibility culling methods. The voxel representation is also utilized for shadow ray intersection test to generate soft shadow effect which results in enhancement of rendering realism. A prototype software system is developed to preprocess and render massive models with the proposed framework. Experimental results show that users can interactively visualize CAD models with hundreds of millions of triangles at high frame rates using our framework.

6. Conclusion and future work

An efficient voxel assisted GPU out-of-core framework has been presented for interactive rendering of large-scale CAD models. The framework has employed an aggressive geometry compression algorithm to produce compact LOD models efficiently while with only slight losses in object quality. The LOD processing has been integrated with voxel based visibility query to achieve better visibility test results and efficient LOD refinement. The framework has been tested by CAD models with tens to hundreds of millions of triangles. Users were able to explorer those models at interactive frame rates on desktop PCs with the prototype software system. The current implementation of the rendering system includes a primary rendering and shadow rendering. Future versions will include many-light and ambient occlusion effect implementations. We are also interested in more efficient voxel data structure compression methods which help to lessen voxel storage size further.