We demonstrate a physically-based technique for predicting the drape of a wide variety of woven fabrics. The approach exploits a theoretical model that explicitly represents the microstructure of woven cloth with interacting particles, rather than utilizing a continuum approximation. By testing a cloth sample in a Kawabata fabric testing device, we obtain data that is used to tune the model's energy functions, so that it reproduces the draping behavior of the original material. Photographs, comparing the drape of actual cloth with visualizations of simulation results, show that we are able to reliably model the unique large-scale draping characteristics of distinctly different fabric types.

In this work we render non-opaque anisotropic media. A mathematical formalism is described in which polarization effects resulting from light/material interactions are represented as transformation matrices.When applying the matrices a skewing is performed to ensure that like reference coordinates are used. The intensity and direction of an extraordinary ray is computed.

We propose a new approach to the problem of generating a simple topologically-closed geometric model from a point-sampled volume data set. We call such a model a Geometrically Deformed Model or GDM. A GDM is created by placing a 'seed' model in the volume data set. The model is then deformed by a relaxation process that minimizes a set of constraints that provides a measure of how well the model fits the features in the data. Constraints are associated with each vertex in the model that control local deformation, interaction between the model and the data set, and the shape and topology of the model. Once generated, a GDM can be used for visualization, shape recognition, geometric measurements, or subjected to a series of geometric operations. This technique is of special importance because of the advent of nondestructive sensing equipment (CT, MRI) that generates point samples of true three-dimensional objects.

The authors propose a methodology that will extract a topologically closed geometric model from a two-dimensional image. This is accomplished by starting with a simple model that is already topologically closed and deforming the model, based on a set of constraints, so that the model grows (shrinks) to fit the feature within the image while maintaining its closed and locally simple nature. The initial model is a non-self-intersecting polygon that is either embedded in the feature or surrounds the feature. There is a cost function associated with every vertex that quantifies its deformation, the properties of simple polygons, and the relationship between noise and feature. The constraints embody local properties of simple polygons and the nature of the relationship between noise and the features in the image.>

Abstract We identify an intermediate coordinate system situated between world coordinates and display coordinates, which exhibits unique features for lighting calculations and for clipping in homogeneous coordinates. Our key contribution is an algorithm for extracting such a coordinate system from a homogeneous viewing transformation that relates WC to DC. The algorithm is based on factoring the transformation into a product of a Euclidean factor and a sparse (computationally cheap) but non‐Euclidean factor. A particularly strong application of the proposed technique is the graphical processing of curved surface primitives, such as what is needed in the PHIGS PLUS viewing pipeline. Furthermore, in PHIGS PLUS the graphical data is retained by the graphics system, therefore, it is possible to perform the factoring of the viewing transformation at creation time, and to take advantage of this factored form at traversal time.

One of the major obstacles in CAD is the lack of available software systems that can effectively manage the massive amounts and diverse types of data necessary to describe designs. In this paper, we focus on this problem by investigating the use of data abstraction, a software engineering principle, as a means of managing the volume and complexity of design data.

Article Free Access Share on Computer graphics in higher education (Panel Session) Authors: Al Bork The George Washington University The George Washington UniversityView Profile , Maxine Brown The George Washington University The George Washington UniversityView Profile , Robin King The George Washington University The George Washington UniversityView Profile , Andries van Dam The George Washington University The George Washington UniversityView Profile , Mike Wozny The George Washington University The George Washington UniversityView Profile , Chairman: James D. Foley The George Washington University The George Washington UniversityView Profile Authors Info & Claims SIGGRAPH '83: Proceedings of the 10th annual conference on Computer graphics and interactive techniquesJuly 1983 Pages 31–33https://doi.org/10.1145/800059.801129Online:01 July 1983Publication History 2citation402DownloadsMetricsTotal Citations2Total Downloads402Last 12 Months1Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

“The User's View of CAD/CAM” will share the experience gained in over 50 man-years of day-to-day use of CAD/CAM systems. Six industry segments are represented in this presentation. In addition, a wide range of systems costing under d50,000 to over d1,000,000 will be discussed.There is good news and bad news. All panelists admit to improved productivity and/or reduced design cycle time, but all is not free. You will hear about what it takes to operate and support CAD/CAM systems. Subjects include facilities planning, cost effectiveness, training, internal support requirements, and more. Here is your chance to hear practical and common sense comments about what CAD/CAM can and cannot do for you.