UBC Theses and Dissertations
Modeling of rocks and ornamental garden stones Ellefson, Christopher J.
Objects in nature are irregular in shape and the human eye is good at identifying regularities and symmetries when it does not expect them. Modeling these natural objects to make them look realistic can often be difficult and time-consuming. An example of these objects are rocks from a Chinese garden. These rocks have many large holes in them. Traditional modeling techniques do not lend themselves well to creating objects with complex and irregular shape. The holes in these rocks are also too large to be handled with bump or displacement maps. This thesis discusses a technique to model ornamental rocks and objects with many large holes in them. A 3D material comprised of holes is made using an appropriate distribution for the holes. A stochastic process is used in creating the holes. Information gathered from pictures of real ornamental rocks is used for the distributions of the random variables used to create the holes This is combined with the base shape of the object using constructive solid geometry. The result is a new object resembling the base shape but with many holes in it. The new shape created is converted to a format which is usable by most rendering systems, in this case a series of triangles. This is done using a three-dimensional grid as an intermediate structure and then outputting triangles.The new object can than be imported into a rendering program. We produced models and images from an implementation and they show that the method results in realistic looking images. These models are used in a virtual reconstruction of the Yuan Ming Yuan, a former imperial garden in China.
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