“Sketch-Based Modeling with the BlobTree”

  • ©Ryan Schmidt, Brian Wyvill, and Mario Costa Sousa

  • ©Ryan Schmidt, Brian Wyvill, and Mario Costa Sousa




    Sketch-Based Modeling with the BlobTree



    Sketch-based modeling provides an intuitive and expressive inter- face for 3D model creation. With the Teddy [Igarashi et al. 1999] system, complex free-form 3D models could be quickly produced using a gesture interface. However, the topological modeling operations implemented in Teddy were limited by the underlying shape representation (triangle meshes). Related systems based on variational implicit surfaces [Araujo and Jorge. 2003] produce smoother ́ results but cannot support complex models. We are exploring the use of hierarchical implicit models (Blob- Trees [Wyvill et al. 1999]) for free-form sketch modeling. a key property of BlobTrees is that the scalar fields defining the under- lying primitives have finite support, and hence local influence on the model. This local influence preserves a “principle of least surprise” that is critical for interactive modeling. We have developed a spatial caching technique [Schmidt et al. 2005] that supports interactive construction of complex BlobTree models, allowing us to experiment with a sketch modeling tool that uses a BlobTree as the underlying shape representation.


    Araújo, B., And Jorge., J. 2003. Blobmaker: Free-form modeling with variational implicit surfaces. In Comunicação ao 120 Encontro Português de Computação Gráfica.
    Igarashi, T., Matsuoka, S., and Tanaka, H. 1999. Teddy: A sketching interface for 3d freeform design. In Proceedings of ACM Siggraph 99, 409–416.
    Schmidt, R., Wyvill, B., And Galin, E. 2005. Interactive implicit modeling with hierarchical spatial caching. In Proceedings of Shape Modeling International 2005. To Appear.
    Wyvill, B., Guy, A., and Galin, E. 1999. Extending the csg tree. warping, blending and boolean operations in an implicit surface modeling system. Computer Graphics Forum 18, 2, 149–158.

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