Roberto Vivó

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This paper presents a new method for realistic real-time rendering of tree foliage. Some approaches to this problem have been presented before but the quality of their results was not maintainable with respect to changes in view vector and observer distance. Our method is based on a hierarchy of images obtained from pre-processing the botanical tree(More)
We present a client/server system that is able to display 3D scenes on handheld devices. This kind of devices have important restrictions of memory and computing power. Therefore, we need to limit the amount of geometry sent by the server to each client. We extract the geometry that is visible for each client and send it. The clients render the geometry(More)
This paper presents a method to obtain a polygonal mesh representing the ramified structure of a tree. We use a method based on L-systems to model the tree. A refining process is applied once the model of the tree is obtained. Soft transitions are achieved in the areas of the tree where there are divisions. In this way, we avoid the possible superimposition(More)
Modeling and rendering of plants and trees requires generating and processing large numbers of polygons. Geometry simplification methods may be used to reduce the polygon count and obtain a multiresolution representation. However, those methods fail to preserve the visual structure of a tree. We propose a different approach: procedural multiresolution. We(More)
Space partitioning techniques are a useful means of organizing geometric models into data structures. Such data structures provide easy and efficient access to a wide range of computer graphics and visualization applications like real-time rendering of large data bases, collision detection, point classification, etc. Binary Space Partitioning (BSP) trees(More)
In this article we present a prototype tool for the modelling of natural elements based on procedural modelling using Random L-systems, or RL-systems. RL-systems are L-systems which are extended using random variables, which permits us to obtain different individuals of the same species based on the same system. The proposed tool is flexible, easily(More)
We present a simple calibration method for computing the extrinsic parameters (pose) and intrinsic parameters (focal length and principal point) of a camera by imaging a pattern of known geometry. Usually, the patterns used in calibration algorithms are complex to build (three orthogonal planes) or need a lot of features (checkerboard-like pattern). We(More)
This paper presents a methodology for integrating synthetic objects into real scenes. We take a set of photographs of the real scene and build a simple image-based model. We use high dynamic range images to build an accurate representation of the lighting in the scene. Then we insert a synthetic object into the model and compute its illumination and shading(More)