Remodelling of Botanical Trees for Real-Time Simulation, D.T. Reynolds, S.D. Laycock, A.M. Day, Theory and Practice of Computer Graphics, Eurographics Association, pages 1-8, 2011

This paper proposes a technique to use virtual trees created with an industry recognised modelling tool. Initially the skeletal structure is extracted and processed to generate a continuous mesh suitable for high quality, real-time rendering and simulation. Utilising the inherent hierarchical structure of botanical trees, the bone system is calculated from existing, low quality geometry. Once an ordered skeleton is available, a low resolution surface is created around the form as a single continuous mesh providing smooth, continuous connections where branches diverge, avoiding artefacts introduced by overlaid surfaces. Creation of the vertices relative to the skeletal structure ensures no miss-classification in assigning bone influence, allowing for realistic animation and effective mesh refinement introduced dynamically using GPU based techniques.

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Real-Time Accumulation of Occlusion-Based Snow, D.T. Reynolds, S.D. Laycock, A.M. Day, The Visual Computer, Springer Berlin Heidelberg, vol 31-5, pages 689-700, 2015

This paper describes a technique to allow the real-time simulation of snowfall accumulation in a dynamic 3D environment. The implementation maps surface-bound accumulation buffers to each object in the scene, forming height-maps of accumulated snow cover. The environment is rendered from above similar to the way shadow mapping is typically produced. However, unique buffer IDs and texture co-ordinates are output within each pixel of the render. A new technique for performing the mapping between buffers is proposed where a series of quads are rendered, one per pixel of the occlusion projection, to map directly visible surfaces to their corresponding accumulation height-map. Blurring is performed on the maps and per-pixel detail is given by procedurally generated normal maps of each surface updated frame by frame. Additional detail and shaping is performed using view-dependent tessellation and the snow surface is created by re-colouring and offsetting the existing scene geometry. This is the first implementation of snow simulation which allows persistent accumulation on a dynamic, moving scene in real-time.

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