Computer Aided Drawing System based on Prediction of Drawing Action Hirokatsu Sou
Ichiro Kanaya
∗
Kosuke Sato
Graduate School of Engineering Science, Osaka University Machikaneyama, Toyonaka, Japan
Graduate School of Engineering Science, Osaka University Machikaneyama, Toyonaka, Japan
Graduate School of Engineering Science, Osaka University Machikaneyama, Toyonaka, Japan
[email protected]
[email protected]
[email protected]
ABSTRACT Computer Aided Design (CAD) systems are widely used recent years. In general, however, designers sketch product images by their own hands during early stages of designing. The authors aim to aid these freehand design by predicting and guiding designer’s drawings using computers and a display-tablet. The computer estimates geometrical figures that the designer is drawing in real-time. The experimental results shows that the proposed system is effective for simple designing processes.
Keywords Design aided system, Prediction of drawing action, User interface
specify figure types (line, circle, parabola, or ellipse) before start drawing or can let the computer guess which type the designers are drawing on. The computer samples designer’s drawing action, tries fitting mathematical models of simple figures onto current input shape, and shows estimated figures to the designer in real-time. The designer can use the estimated figures as a drawing guide. The curve of 0 ≤ u ≤ u1 in Figure 1 is the drawing curve which is drawn by the user. The computer estimates C(u), 0 ≤ u ≤ u2 from this input and outputs the estimated curve.
1. INTRODUCTION Computer Aided Design (CAD) systems are indispensable in industrial designs. Freehand sketches, however, have been drawn with pen and ink. Since the CAD systems have been hard to use for designers to draw their images in their mind. In this paper the authors propose a novel design-aid system that helps designers draw their image intuitively on computers. The system reads designers mind for helping their drawing.
2. REAL-TIME PREDICTION OF DRAWING When a designer sketches some models, he/she may well draw figures with splitting them into some simple parts (e.g., curves, circles, and ellipses) and draws each part at once without lifting his/her pen from the canvas. The authors focus on support of drawing the simple parts of figures: a line, circle, parabola, and ellipse. When a designer draws a figure on a computer screen (or a display tablet), the computer estimates whole shape of the figure that the designer is intending to draw before they complete drawing. Designers can Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. ACE 06, June 14-16, 2006, Hollywood, California, USA. Copyright 2006 ACM 1-59593-380-8 /06/0006 ...$5.00.
Figure 1: Drawing curve.
3.
SYSTEM STRUCTURE
Figure 2 shows external appearance of the system. This system is made from a display-tablet and a PC (Mac).
3.1
System Design
The proposed system looks like a normal painting application software at first glance. Users of the proposed system can freely draw anything on the display-tablet. When the user starts drawing some curves, several complete curves appears on the screen so that the user is guided for further drawing. When the user starts drawing, the computer obtains his/her drawing action. This system estimates the parameter of the whole figure that
example figures to be drawn for practice. Through this practice, the examinees got used to the system. The examinees were allowed to change delay-time of appearance of suggested curves as they wanted. After this practice, the examinees copied the example figure with and without the automatic suggestion. Then, the authors carry out a questionnaire for the examinees. One of questions asked “ Were you able to sketch geometrical figures as you were intended to draw?”. The examinees gave an answer with an evaluation standards of five levels, “ 1 (bad)∼5 (good)” to this question in the each case with and without this system.
Figure 2: External appearance of the system. the user is going to draw from obtained drawing action. This system shows the estimated figure to the user. This process continues until the user finishes drawing.
3.2 System Implementation Figure 3 shows a prototype application and examples of dynamically estimated figures (line, circle, parabola, and ellipse) by the system. User’s input is colored in black. Other estimated figures are colored in various colors. Area A in Figure 3 is the drawing area. Area B is the area where the user chooses the figure types (line, circle, parabola, or ellipse) which he/she is going to draw. Area C is the area to change delaytime of appearance of suggested curves.
Figure 4: The result of the experiment. The transition of evaluated value from the case without this system to the case with it. Figure 4 shows that the transition of evaluated value from the case without this system to the case with it. The result showed that most people were able to draw geometrical figures that they imaged more intuitively using the proposed system.
5.
CONCLUSIONS AND FUTURE WORK
The authors have created an effective and powerful tool for design sketches. The system helps designers draw their images intuitively on computer screens by “ reading designers’ minds” and showing suggested curves/lines in real-time. The experimental results have shown the effectiveness of our approach. Following are left for future works. 1) To support drawing on a real canvas. Projectors and cameras will be used for presenting and sensing drawings on the real canvas. 2) To support drawing free-form curves. Deeper knowledge on curvatures of free-form curves and designers’ drawing motions will be required for this purpose.
6.
REFERENCES
[1] I.Kanaya, Y.Nakano, K.Sato: Simulated designer’s eyes —Classification of aesthetic surfaces—, Proc. Int. Conf. on Virtual Systems and MultiMedia ‘03, pp.289-296, 2003.
Figure 3: Screen-shot of the prototype application. The proposed system displays the estimated figures.
4. EXPERIMENT ABOUT DESIGN SKETCH The authors performed an experiment to confirm that the proposed system is effective for freehand design. The eighteen examinees were made up of college students and graduate students ranging in age from 22 to 24 years old. Firstly, we showed the examinees
