World Space Surface Pasting

Feature Oriented Surface Pasting

By using a procedure known as pasting, detailed features are added to composite spline surfaces in a multi-layered fashion by means of an efficient displacement scheme. The feature orientation is arbitrary, and the underlying domains may be partially overlapping and non-linearly transformed. As a result, this technique allows us to model surfaces by interactively changing displacements, control vertices, or the domain layout.

Domain Space User Interface Vs World Space User Interface

To paste features on a base surface, we first transform the domain of the original feature surface so that it fits inside the domain of the base surface. In addition, the position of the feature also depends on the transformed feature domain, as in the pictures below. Therefore, editing features (translation, scaling, rotation, etc., except changing CVs) is inherently a domain transformation operation.

Composite Surface

Another Example

Thus, we can built a domain space user interface, which allows the user to edit the domains of all features and base surfaces in order to adjust the shape and position of the features or the base surfaces.

However, from the user point of view, working with the 2D domains is an indirect way of editing the 3D model. It would be nice to have direct manipulation on the 3D surfaces instead of domains, as the user usually only concerns about the model.

The World space user interface attempts to hide the domains from the user and lets him/her interact with the 3D model directly. All the user's actions are mapped into underlying operations of the domains.

A snapshot of the World Space Interface currently under development

In the picture, there is a 3D manipulator, which consisted of a few draggers, used for transforming the purple feature. Please look at this picture for its functionality.