Sanghun Nam

SMI 2012: Short SPACESKETCH: Shape modeling with 3D meshes and control curves in stereoscopic environments

This paper introduces SPACESKETCH, a new kind of sketch-based modeling system that can sketch free-form surface in space. This modeling system combines the advantages of a direct mesh-based sketch in which the user can draw the mesh directly in the space by moving the wand and the control curve sketch to express the detailed shape of the model. The created surface is also divided by using the control curve so that different resolution surfaces can be set for each surface and partially complicated parts can be sketched. While using SPACESKETCH, we introduced the advantages of using a new interface that uses mesh-based sketch and control curve sketch simultaneously to create various models and how to apply multi-resolution. Through this process, we show that mesh-based sketch and control curve sketch simultaneously to complement each other in a multi-resolution real time environment is very useful in concept sketching in a 3D environment using a spatial input device.

6DOF Wireless Tracking Wand Using MARG and Vision Sensor Fusion

We present a low cost battery-powered 6-degree-of-freedom wireless wand for 3D modeling in free space by tri-axis Magnetic, Angular Rate, Gravity (MARG) and vision sensor fusion. Our approach has two stages of sensor fusion, each with different algorithms for finding 3D orientation and position. The first stage fusion algorithm, a complementary filter, utilizes MARG sensors to compute 3D orientation relative to the direction of gravity and earths magnetic field in a quaternion format, which was adjusted with compensations for magnetic distortion. The second stage fusion algorithm, a Kalman filter, utilizes accelerometer data and IR marker velocity to compute 3D position. In order to compute the IR marker linear velocity along the optical axis (the z-axis), we present a simple and efficient image-based technique to find the distance of the object from the camera using blob area pixels in the image. Our fusion (inside-in and outside-in) approach efficiently solves short time occlusion, needs of frequent calibration, and unbounded drift problems involved in numerical integration of inertial sensors data and improves the degrees of freedom at low cost without compromising accuracy. The results are compared with a leading commercial magnetic motion tracking system to demonstrate the performance of the wand.

Hybrid interface of a two-dimensional cubic Hermite curve oversketch and a three-dimensional spatial oversketch for the conceptual body design of a car

A spatial modelling system with a new interface which is optimized for automotive design is proposed in the conceptual modelling phase. In the initial sketch stage to set the volume and the ratio of the car, the automotive styling is created using a two-dimensional plane sketch with an accurate input and a designer-friendly interface. The character lines, which have important implications in the design of the car, are drawn with a curve-based oversketch. The shape of the car is modified using area-based modification. A completed two-dimensional model consists of converting the character lines to a three-dimensional car model. In the three-dimensional spatial oversketch stage, the edge and mesh on the surface are deformed by viewing the three-dimensional shape of the vehicle with various views using a spatial input device and stereoscopic display. Edge-based deformation modifies single or multiple edges while maintaining continuity between the surfaces. A sculpting technique is applied to execute special shapes such as the accent lines and the strake lines. A sketch system which can be used by designers to perform three-dimensional spatial modelling is proposed.

Dual projection-based VR system for the light weight motion-based driving simulator

This paper proposes a projection-based VR system using the window and camera projection paradigms simultaneously. This technique can be applied to the Driving Simula or, which consists of 6 D.O.F. motion platform and projection screens separated from the motion platfor.

Intuitive Change of 3D Wand Function in Surface Design

According to the target model for a designer to sketch, an effective style or shape of input device can be defined differently. The spatial sketch system that supports various types of wand can help to sketch efficiently. We suggest the idea of changing wand style by altering the posture of a 3D wand. This method allows a designer to work in intuitive ways without being interrupted by complicated menus. We implement the surface drawing and merging technique with the grid based data structure which deals with multiple strokes from various types of wand.

Spatial sketching with the auditory reflection for the plausible virtual conceptual design

Most industrial designers work with a pencil and some plane papers. In spite of the paper-based plane modeling data by these designers, the majority of the industrial modeling data for manufacturing are based on the spatial concept. While converting the designers 2D drawing data to the digital form of 3D industrial modeling, designers intention is often misunderstood or misinterpreted. If the designer can use the spatial modeling tool in their conventional way, it is easy to express their intention and there is no need to transform the 2D drawings to 3D model.