Freeform Strokes Research Articles

Progressive sketching with instant previewing

Sketch-based modeling uses freeform strokes as basic modeling metaphor and the modeling process typically involves two phases: sketching and sculpting. This paper presents a method to enhance the sketching phase to have the features of both sketching and sculpting. The key idea of the method is progressive sketching with instant previewing, which has the capacity of intuitively creating complex initial shapes that interpolate all the sketched strokes. The process lets the user iteratively sketch and meanwhile updates the reconstructed 3D shape instantly, which enables the user to be aware of the up-to-date shape. The underlying technique supporting this process is a novel surface construction algorithm that produces 3D triangular mesh models typically with only a single connected component and gradual shape changes during iterative sketching as well. To demonstrate the capability of the method, a sketching-based modeling prototype is also developed, which includes both sketching and sculpting functions. Experiments show that the proposed method can allow users to intuitively and flexibly create and edit 3D models even with complex topology, which is usually difficult for conventional sketch-based modeling systems.

Deco: a design editor for rhinestone decorations.

Young people enjoy applying rhinestones to personal goods, such as notebook PCs, mobile phones, and digital cameras. However, novices often find designing rhinestone decorations difficult because they must consider such factors as rhinestone width and spacing. So, many people employ off-the-shelf design sheets or have professionals decorate their items. To solve this problem, I have developed an interactive editor for designing rhinestone decorations. Users draw free form strokes; the system then automatically places virtual rhinestones to create an image in which no rhinestones overlap. Users can create a stencil of the image and use it to place the real rhinestones on objects.

EasyToy: plush toy design using editable sketching curves.

EasyToy is an industrial plush toy design system for novices. Editable sketching curves combine the advantages of free-form strokes and the controllability of B-spline curves. Users can continuously edit each curve to refine designs. EasyToy provides a small set of simple tools with which users can easily construct sophisticated toy models comparable to those that professional systems produce.

Face poser

This article presents an intuitive and easy-to-use system for interactively posing 3D facial expressions. The user can model and edit facial expressions by drawing freeform strokes, by specifying distances between facial points, by incrementally editing curves on the face, or by directly dragging facial points in 2D screen space. Designing such an interface for 3D facial modeling and editing is challenging because many unnatural facial expressions might be consistent with the user's input. We formulate the problem in a maximum a posteriori framework by combining the user's input with priors embedded in a large set of facial expression data. Maximizing the posteriori allows us to generate an optimal and natural facial expression that achieves the goal specified by the user. We evaluate the performance of our system by conducting a thorough comparison of our method with alternative facial modeling techniques. To demonstrate the usability of our system, we also perform a user study of our system and compare with state-of-the-art facial expression modeling software (Poser 7).

A Sketch-Based Interface for Modeling Myocardial Fiber Orientation

This article proposes a sketch-based interface for modeling muscle fiber orientation of a 3D virtual heart model. Our target was electrophysiological simulation of the heart and fiber orientation is one of the key elements to obtaining reliable simulation results. We designed the interface and algorithm based on the observation that fiber orientation is always parallel to the surface of the heart. The user specifies the fiber orientation by drawing a freeform stroke on the object surface. The system first builds a vector field on the surface by applying Laplacian smoothing to the mesh vertices and then builds a volumetric vector field by applying Laplacian smoothing to the voxels. We demonstrate the usefulness of the proposed method through a user study with a cardiologist.