| Author | Natthavika Chansri |
| Call Number | AIT Diss. no.ISE-12-13 |
| Subject(s) | Rapid prototyping
|
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Design and Manufacturing Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ISE-12-13 |
| Abstract | Freehand sketching with a pencil and paper is commonly seen being used as it is an effective convenient way to express and to communicate rough ideas in various occasions, especially in the early stage of design, but a sketch-to-3D translation process makes a paper-based freehand sketch less attractive due to a lack of technology support. A designer is normally required to create a CAD model manually. Sketch-based modeling from a paper, especially an overtraced freehand sket ch, has been a challenge because enriched information obtained during sketching is available in the form of a batch of points. A successful development of this sketch-based modeling is foreseen to preserve natural and convenient way of describing ideas while these ideas are visualized clearly and explored easily in subsequent operations, including in rapid prototyping (RP) process where a physical prototype is fabricated layer by layer from a 3D CAD model. Rapid prototyping is one of the five key technologies for rapid product development (RPD). RP allows designers and customers to realize and experience their ideas quickly. Besides traditional creation of a 3D CAD model on commercial software, reverse engineering (RE) makes it happens for the 3D CAD model to be created from its physical object. Furthermore, several researchers have improved and realigned steps in both processes to make their direct integration work more effectively. Similar concept should also be explored to create direct integration between sketch-based modeling and rapid prototyping, instead of leaving a sketch-based modeling be a stand-alone technology. Presented in this dissertation is a research fo r direct fabrication of a physical prototype from a paper-based overtraced freehand sketch to speed up the realization of an idea. A system is developed to transform enriched information on a paper-based overtraced freehand sketch to be a stack of contours that can be directly used for generating commands for fabricating a physical prototype layer by layer. Two key modules: single line drawing identification and contours genera tion are developed for tackling two critical tasks: information extraction and direct integration with RP. First and foremost, additional information must be created from only available information, a batch of point in this case. The first module is developed for transforming a paper-based overtraced freehand sketch to be a single line drawing such that additional information about the sketch (i.e., the number of lines and their starting points and endpoints) becomes available. The nature of overtraced strokes that is a mixture of overlapped lines, parallel lines, short lines, long lines, and space between lines makes it difficult to identify which points in the batch should be kept or removed for forming a single line drawing. Therefore, all points in the batch are considered to be important, and used to create their representative, a thick line sketch, before a single line drawing is extracted. The second module is developed for a ligning steps to be taken after a single line drawing is obtained in order to start construc ting a physical model earlier. It is an attempt to bypass 3D model reconstruction and STL conversion steps to speed up the process. After obtaining depth information from the drawing, all faces are illustrated on their principal vertical planes where uniform direct slicing is conducted layer by layer simultaneously on these planes. Segments, obtained from the faces, are connected to form a closed contour for each layer. The output of this system is a stack of closed contours that will be used to generate commands directly for fabricating a physical prototype layer by layer. The proposed system can be used for objects that compose of planar surface whose edges are clearly presented on the single-view draw ings (i.e., flat-face pol yhedron). Algorithms developed in this research have been implemented on LabVIEW. With a simple input format, sketch-based modeling and rapid prototyping processes can be run from different locations. |
| Year | 2011 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ISE-12-13 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Industrial Systems Engineering (ISE) |
| Chairperson(s) | Pisut Koomsap; |
| Examination Committee(s) | Bohez, Ir Erik L. J. ;Dailey, Matthew N.; |
| Scholarship Donor(s) | Faculty of Engineering, Kasetsart University, Si Racha campus ;Asian Institute of Technology Fellowship; |
| Degree | Thesis (Ph. D.) - Asian Institute of Technology, 2012 |