Plant Structure Representation, Simplification And Drawing Faithful To Botanical Rules

The morphology and structure of a plant is not only a reflection of the growth state,but also influences and determines the growth and development of the plant.So it makes great sense for the study of morphology and the structure drawing which are faithful to botanical rules.In order to describe the tree topology in a more reasonable way for modeling and biological calculation,an approach which makes use of ternary tree data structure to describe the tree topology is introduced in this thesis.In the approach,mapping between the data structure of ternary tree and the topology structure of the plant is built up naturally,which can present the biological properties of plant axes and the relationships among plant axes with different orders.An axis simplification approach based on ternary tree data structure is also introduced in this thesis.The process of tree axis simplification has explicit botanical meaning,and biological properties are considered,and the simplified tree axes are kept as faithfully as possible to the crown canopy envelope's shape,volume and biomass distribution inside it.In the thesis,the ternary tree-based topology representation and the approach of tree axis simplification are employed in the simplification of a tree model to generate Levels of Detail(LOD) models.The LOD results are drawn with hardware acceleration based on Graphics Processing Unit(GPU) programming.Experimental results show that the structure simplified tree not only well match the tree's botanical features,but also keep visual effect in some degree,and the transition between levels of detail of models is smooth.Moreover,the approach is appropriate to the graphics hardware acceleration.In addition,the growth dynamic process is restored by interpolation according to the growth rules in a growth cycle.The combination of LOD and Geometry Instancing technique is employed to accelerate the drawing of plantation stand.