ADVANCED GRAPHICS TECH & QUALITY OF EXPERIENCE FACTORS IN VIRTUAL ENVIRONMENTS

先进的图形技术

• 批准号: 6326169
• 负责人: Frederick P BROOKS
• 金额: $ 15.14万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-15 至 2001-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6326169
• 关键词: biomedical resource; computers; technology /technique

Many models are too complex for walkthroughs to be interactive, which requires an update rate of at least 20 frames/second. If, for example, one has a graphics engine capable of rendering 2 million polygons/second, models of more than 100 thousand polygons cannot be smoothly traversed by brute force alone. Over the 1995-96 year, we developed a variety of techniques for making interactive walkthroughs of massive models possible. During 1996-97, we studied how to integrate several of these techniques into a single rendering framework. This is non-trivial, because in general each technique needs its own particular data structure; these are incompatible; and machine memories cannot contain multiple data structures of a massive model. We achieved considerable success. In August, at the annual SIGGRAPH meeting, we demonstrated interactive walkthrough, at speeds of 4-20 frames/second, of a massive model of some 13 million polygons. One of the techniques used was to fill the model space with some 10,000 cells that lay along the paths most viewers would want to take. For each cell, a box, some 6x cell size on each side, was constructed. All the geometry outside the box is rendered onto meshes associated with each box wall, using projective textures, as a pre-process. At run time, only the simplified projective textures are rendered for all the geometry outside the box the viewer currently inhabits. The geometry inside the box is rendered using level-of-detail simplfication as described in Subproject 9 above. Only the geometry in the view frustum is rendered; a hierarchical culling technique enables these decisions to be made very rapidly. Yet another hierarchical culling technique is used to avoid rendering objects that are occluded by single objects or groups of objects nearer the viewer's eye.

许多模型太复杂，无法进行交互， 这需要至少20帧/秒的更新速率。 如果由于 例如，一个图形引擎能够渲染200万个 多边形/秒，超过10万个多边形的模型不能 仅凭蛮力就能顺利通过 在一九九五至九六年度，我们 开发了各种技术来制作互动式步行广告 大规模模型的可能性。 在一九九六至九七年度，我们研究如何 将这些技术中的几个集成到单个渲染中 框架. 这是不平凡的，因为一般来说， 需要自己的特定数据结构;这些是不兼容的;以及 机器存储器不能包含大量的多个数据结构。 模型 我们取得了相当大的成功。 8月，在一年一度的 SIGGRAPH会议上，我们展示了交互式演练，速度 4-20帧/秒，大约1300万个多边形的大规模模型。 使用的技术之一是用一些 10,000个细胞沿着大多数观众想走的路。 对于每个细胞，构建每侧约6倍细胞大小的盒子。 框外的所有几何体都将渲染到关联的网格上 每一个盒子的墙壁，使用投影纹理，作为一个预处理。 在 运行时，只有简化的投影纹理被渲染为所有 观察者目前所处的盒子之外的几何形状。 的 使用细节层次渲染框内的几何体 如上文子项目9所述的简化。 只有几何形状 在视图截头体渲染;分层剔除技术 使这些决定能够非常迅速地做出。 又一 分层剔除技术用于避免渲染对象， 被附近的单个物体或成组物体遮挡 观众的眼睛。