Research On Interaction And 3D Modeling Based On Freehand Sketching

It is really difficult to convert 3D design intent into computer using traditional WIMP-style (Window, Icon, Menu, Pointing Device) GUI (Graphical User Interface). Firstly, users have to decompose their design intent into several independent simple elements, such as points, curves and surfaces, and later group and assemble those elements into one solid shape using complex modeling and interactive methods. The evolution of computer-aided design systems has been remarkable increased in functionality, and the fact is that the usability was undesirably decreased. The complex modeling procedures and disturbing interactive methods make a wide gap in relation to traditional paper and pencil interaction during initial designing stages. The abundance of existing functions and the strictness of the interaction tend to interfere with the users' mind and disturb their creative processes. So it is not surprising that designers continue to rely on paper and pencil in the initial stages of the design, and resort to the computer only in the final stages when the shape of the object being created is already established.People have long been used to express visual message through simple and quick sketch. Freehand sketching user interface has uncovered its power of achieving fluent interaction between users and computers in performing graphical tasks. In freeform user interface, each stroke sketched by users will be percepted by system. The strokes can not only express graphical designing intent, but also can transfer designing commands to system. The basic difference between freehand sketching UI and traditional WIMP-style UI is that it analyzes and snaps user designing intent instead of applying simple state matching to drive system modeling.Here, we keep our focus on 3D modeling and interaction based on freehand sketching UI. Firstly, the paper introduces existed researches and achievements with respect to freeform modeling and interaction. Then chapter 2nd describes a 3D conceptual designing method based on freehand sketching. Be different with obverse modeling method described in chapter 2nd, chapter 3rd introduces an application of freehand sketching applied in reverse engineering modeling: curves construction onto point cloud based on sketches. To reveal more advantages of sketching UI, chapter 4th describes a 3D solid flower modeling method based on sketches. This method thoroughly shows the flexibility and creativity of sketches on modeling of natural biology which owns complex geometrical shapes. In chapter 5th, we introduce a dragging interactive method to locate objects freely in space, and successfully apply it into point cloud blending modeling. In chapter 6th, we present a new user interface TGFUI in mobile platform which featured by transparent window and sketch interface. The paper ends with final summary as well as the prospect of the potential applications and future research directions.All creative achievements in this paper list as follows:(1) A framework based on sketches and driven by gestures is given to support 3D conceptual design.We separate 3D conceptual design procedure into several sub-parts, such as sketch recognition, sketch editing, gesture analysis, solid/surface creation, solid/surface editing, et al. The whole framework is controlled by a finite state machine. It takes sketching rules and semantic finite state machine as designing methods, and describes the way to capture, express and understand 3D designing intent by sketches. It supports initial 3D conceptual designing very well. Based on this framework, we realized a prototype system. It takes electric pen and tablet as input device, and it can create complex scenes easily and freely.(2) Present a sketching modeling method applied in reverse engineering.This paper presents a sketching application in reverse engineering. Users can freely draw curves onto point cloud, and the constructed curves can be easily grouped into model's curve network. Experiments show that the final curves onto point cloud can be well suited to sequent surface constraint fitting module. This sketching method enriches the modeling methods in reverse engineering.(3) Present a sketching method suited to model natural biology of complex shapes This paper introduces freehand sketching into flower solid modeling procedure.We separate modeling into two independent parts: structural modeling and geometrical modeling. Both parts take several sketching methods and gestures into modeling procedures. Experiments show that our method can create vivid 3D flower easily, quickly and rationally. We also propose a method to make the flower waterproof and finally reform flower solid modeling procedure effectively.(4) Propose a method to locate object freely in space based on dragging operationThis paper presents a method to locate objects freely onto point cloud. It doesn'trely on any topology information, so it can be applied directly to locate objects onto several other types of surface model. We apply this method successfully into point cloud blending modeling.(5) Propose a new user interface in mobile platform: TGFUIIt's competitive between view region and framework region in traditional UI. To layout many icons, buttons or menus in screen, the space of view will be compressed relatively. The most important feature of TGFUI is that all the icons, buttons and menus are transparent and can be layout freely in screen. The view region will cover whole screen, and the competitive relationship between view and framework region is removed. To reduce the usage of icons, buttons and menus, TGFUI introduces gestures. Users can send UI message or edit image, graphics freely by gestures. To overcome the ambiguity of gesture semantic, TGFUI also introduce the feedback scheme to allow users modify the wrong recognition result.