Image Based Real-Time and Realistic Forest Rendering and Forest Growth Simulation

Abstract

Real-time and realistic rendering of forest is an important and a difficult work in computer graphics and digital forestry. An image based real-time and realistic forestrendering software is developed in this paper. Three orthogonal billboards are used to represent the geometry and material of a tree, so that the 3D perception is enhanced and weak parallax of usual images based approaches is avoided. Shadows of all trees on the plat ground are generated through the stencil buffer, shadow projection and a mixture of the shadow with grass texture. Different billboards are chosen on the viewing direction and the lighting direction, so that the effect of object torsion due to poor image direction is avoided. Forest growth, forest rendering in different lighting conditions, navigation inside a forest, and flying over a forest are all simulated.

Billboards for Tree Simplification and Real-Time Forest Rendering

“…The data in Table 1 show that we have received interactive frame rates even for a complex scene with thousands of trees. We also compare the results with the previous generation of rendering system [18] . Fig 7 is a screenshot of Scene 2 in the old system.…”

“…Fig 7 is a screenshot of Scene 2 in the old system. Table 2 demonstrates the power of our new system: Although the total triangles of the models are much larger than that rendered in the old system, the fps is larger than the old one and the new system provides more geometric details in realistic visualization than [18]. …”

“…It is based on the rendering system developed by Zhang et al [18] restricted to billboards rendering . Adaptations and new techniques exposed hereby were added to the system to achieve fast efficient rendering and realistic visualization.…”

The dynamic simulator of forest evolution

“…They can zoom-in/zoom-out, control both view point and viewing direction to better analyze the ecological simulation. In order to render forest scene of large scale fast and enhance navigation experience as well, we adopt a -billboard‖ rendering technique [4], preparing a set of textures of simulated species which is faithful to botanic knowledge on several size levels to substitute over-simplified tree geometry. Therefore, the rendered scene looks natural and realistic.…”

“…To achieve fast and realistic visualization of forest virtual scene, we further adopt the -billboard‖ rendering technique [4], adding texture images of different species of trees instead of over-simplified tree geometry to realize natural navigation. After the computation and rendering of the forest evolution is finished every evolution cycle, users can walk through the forest scene interactively.…”