Abstract: Quantitative simulation of plant morphological structure and light distribution in canopy is one of the important methods to evaluate photosynthesis and yield potential. Taking loquat as an example, this paper adopts parametric single tree modeling tool ParaTree to construct 3D individual loquat canopy models; builds terrain surface model based on Inverse Distance Weighted（IDW） method. According to tree distribution rule, it populates tree models on the terrain surface to generate virtual loquat group scene. The whole scene consists of triangular facets as basic elements. It uses radiosity to simulate the light radiant transfer and light distribution in virtual loquat group canopy, calculates  irradiation of each triangular facets, which is useful for simulating loquat canopies utilization efficiency under different planting density, and optimizes loquat plant design.

Key words: radiosity, virtual plant, orchard, light distribution

摘要： 利用计算机定量化模拟植物形态结构和冠层内的光分布是评估植物光合作用潜力与潜在产量的重要方法。以枇杷为例，采用参数化单树建模工具ParaTree构建单株三维枇杷冠层模型，基于反距离加权插值法IDW建立地形表面模型；根据枇杷果园的树木分布情况，把单株木模型“种植”于地形表面，形成虚拟枇杷果园场景。整个三维场景以三角形面元为基本图元表达，利用辐射度算法模拟虚拟枇杷果园冠层内的光传输与光分布，计算到达每片三角形面元的光辐射强度，可模拟不同种植密度下枇杷果园冠层对光的利用率，为枇杷的种植设计提供参考。

关键词: 辐射度, 虚拟植物, 果园, 光分布