Interactive Rendering of Trees with Shading and Shadows

The goal of this paper is the interactive rendering of 3D trees covering a landscape, with shading and shadows consistent with the lighting conditions. We propose a new IBR representation, consisting of a hierarchy of Bidirectional Textures, which resemble 6D lightfields. A hierarchy of visibility cube-maps is associated to this representation to improve the performance of shadow calculations. An example of hierarchy for a given tree can be a small branch plus its leaves (or needles), a larger branch, and the entire tree. A Bidirectional Texture (BT) provides a billboard image of a shaded object for each pair of view and light directions. We associate a BT for each level of the hierarchy. When rendering, the appropriate level of detail is selected depending on the distance of the tree from the viewpoint. The illumination reaching each level is evaluated using a visibility cube-map. Thus, we very efficiently obtain the shaded rendering of a tree with shadows without loosing details, contrary to mesh simplification methods. We achieved 7 to 20 fps fly-throughs of a scene with 1000 trees.

[1]  Shree K. Nayar,et al.  Reflectance and texture of real-world surfaces , 1997, Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition.

[2]  Manuel Menezes de Oliveira Neto,et al.  Relief texture mapping , 2000, SIGGRAPH.

[3]  Nelson L. Max,et al.  Hierarchical Rendering of Trees from Precomputed Multi-Layer Z-Buffers , 1996, Rendering Techniques.

[4]  Richard Szeliski,et al.  The lumigraph , 1996, SIGGRAPH.

[5]  Gernot Schaufler Per-Object Image Warping with Layered Impostors , 1998, Rendering Techniques.

[6]  F. E. Nicodemus,et al.  Geometrical considerations and nomenclature for reflectance , 1977 .

[7]  John Snyder,et al.  Rendering with coherent layers , 1997, SIGGRAPH.

[8]  Jason Weber,et al.  Creation and rendering of realistic trees , 1995, SIGGRAPH.

[9]  Dinesh Manocha,et al.  Visibility culling using hierarchical occlusion maps , 1997, SIGGRAPH.

[10]  Marc Levoy,et al.  Light field rendering , 1996, SIGGRAPH.

[11]  A. Lindenmayer,et al.  Developmental models of herbaceous plants , 1990 .

[12]  David Salesin,et al.  Surface light fields for 3D photography , 2000, SIGGRAPH.

[13]  Oliver Deussen,et al.  Hierarchical Image-Based Rendering using Texture Mapping Hardware , 1999, Rendering Techniques.

[14]  Fabrice Neyret,et al.  Interactive Volumetric Textures , 1998, Rendering Techniques.

[15]  A. James Stewart,et al.  Fast Horizon Computation at All Points of a Terrain With Visibility and Shading Applications , 1998, IEEE Trans. Vis. Comput. Graph..

[16]  A. James Stewart Hierarchical Visibility in Terrains , 1997, Rendering Techniques.

[17]  François X. Sillion,et al.  Conservative volumetric visibility with occluder fusion , 2000, SIGGRAPH.

[18]  Gavin S. P. Miller,et al.  Lazy Decompression of Surface Light Fields for Precomputed Global Illumination , 1998, Rendering Techniques.

[19]  Richard Szeliski,et al.  Layered depth images , 1998, SIGGRAPH.

[20]  David Salesin,et al.  Hierarchical image caching for accelerated walkthroughs of complex environments , 1996, SIGGRAPH.

[21]  Peter Shirley,et al.  Visual navigation of large environments using textured clusters , 1995, I3D '95.

[22]  Jean-Michel Dischler,et al.  Efficiently Rendering Macro Geometric Surface Structures with Bi-Directional Texture Functions , 1998, Rendering Techniques.

[23]  Wolfgang Stuerzlinger,et al.  A Three Dimensional Image Cache for Virtual Reality , 1996, Comput. Graph. Forum.

[24]  Matthias Zwicker,et al.  Surfels: surface elements as rendering primitives , 2000, SIGGRAPH.

[25]  Ricki Blau,et al.  Approximate and probabilistic algorithms for shading and rendering structured particle systems , 1985, SIGGRAPH.

[26]  Lance Williams,et al.  Casting curved shadows on curved surfaces , 1978, SIGGRAPH.

[27]  Tsukasa Noma Bridging between Surface Rendering and Volume Rendering for Multi-resolution Display , 1995, Rendering Techniques.

[28]  Nelson L. Max,et al.  Rendering Trees from Precomputed Z-Buffer Views , 1995, Rendering Techniques.

[29]  Shenchang Eric Chen,et al.  QuickTime VR: an image-based approach to virtual environment navigation , 1995, SIGGRAPH.

[30]  Daniel Thalmann,et al.  Rendering hair using pixel blending and shadow buffers , 1991, Comput. Animat. Virtual Worlds.

[31]  Joëlle Thollot,et al.  Conservative visibility preprocessing using extended projections , 2000, SIGGRAPH.