This paper describes a framework for capturing geological structures in a 3D block model and improving its spatial fidelity given new mesh surfaces. Using surfaces that represent geological boundaries, the objectives are to identify areas where refinement is needed, increase spatial resolution to minimize surface approximation error, reduce redundancy to increase the compactness of the model and identify the geological domain on a block-by-block basis. These objectives are fulfilled by four system components which perform block-surface overlap detection, spatial structure decomposition, sub-blocks consolidation and block tagging, respectively. The main contributions are a coordinate-ascent merging algorithm and a flexible architecture for updating the spatial structure of a block model when given multiple surfaces, which emphasizes the ability to selectively retain or modify previously assigned block labels. The techniques employed include block-surface intersection analysis based on the separable axis theorem and ray-tracing for establishing the location of blocks relative to surfaces. To demonstrate the robustness and applicability of the proposed block merging strategy in a more narrow setting, it is used to reduce block fragmentation in an existing model where surfaces are not given and the minimum block size is fixed. To obtain further insight, a systematic comparison with octree subblocking subsequently illustrates the inherent constraints of dyadic hierarchical decomposition and the importance of inter-scale merging. The results show the proposed method produces merged blocks with less extreme aspect ratios and is highly amenable to parallel processing. The overall framework is applicable to orebody modelling given geological boundaries, and 3D segmentation more generally, where there is a need to delineate spatial regions using mesh surfaces within a block model.

中文翻译：

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矿体结构建模：给定地质边界网格面的区块合并算法和区块模型空间重构策略

本文描述了一个框架，用于在 3D 块模型中捕获地质结构并在给定新网格表面的情况下提高其空间保真度。使用代表地质边界的表面，目标是识别需要细化的区域，增加空间分辨率以最小化表面近似误差，减少冗余以增加模型的紧凑性并逐块识别地质域。这些目标由四个系统组件实现，它们分别执行块表面重叠检测、空间结构分解、子块合并和块标记。主要贡献是坐标上升合并算法和灵活的架构，用于在给定多个表面时更新块模型的空间结构，它强调了选择性保留或修改先前分配的块标签的能力。所采用的技术包括基于可分离轴定理的块表面相交分析和用于确定块相对于表面的位置的光线追踪。为了在更窄的设置中证明所提出的块合并策略的稳健性和适用性，它用于减少现有模型中的块碎片，其中没有给出表面并且最小块大小是固定的。为了获得进一步的洞察力，随后与八叉树子块的系统比较说明了二元分层分解的内在约束和跨尺度合并的重要性。结果表明，所提出的方法产生的合并块具有较少的极端纵横比，并且非常适合并行处理。整体框架适用于给定地质边界的矿体建模，以及更普遍的 3D 分割，其中需要使用块模型内的网格表面来描绘空间区域。