2D and 3D CAD


1. The aim of this project is to understand the basic nuances of 2D and 3D CAD projects. For the purpose of 2D CAD the project aimed at understanding the difference between Vector and Raster images and understand the procedure of using INKSPACE software to convert Raster images into Vector Images. In 3D CAD the aim was to develop a simple beam structure in ANSYS and undertake the stress analysis of the structure in case of Hogging Loads.


2. A Raster graphics or bitmap image is a dot matrix data structure represented by rectangular pixels. They are stored in image files with varying formats. Raster graphics are resolution dependent, meaning they cannot scale up to an arbitrary resolution, without loss of apparent quality. This can be scaling up any Raster GRaphics Image.

3. Vector Graphics are computer graphics image that are defined in terms of 2D points, which are connected by lines and curves to form polygons and other shapes. Each of these points have a definite x- and y- coordinates. Vector graphics are commonly found in SVG, PDF or AI graphic file format.

4. Vector Graphics are capable of scaling up to the quality of the device rendering them. They are better suited for Typesetting or Graphic Design.

5. Vector art is ideal for printing since art is made of a series of mathematical curves. It will print very crisply even when resized. A Vector Logo on a small sheet of copy paper and then enlarge the same logo onto a billboard as required.

Conversion of Raster to Vector Graphics

6. A Raster Image can be converted into a Vector image using any software illustration. In this assignment, the software INKSCAPE has been used.


7. One method for conversion of a Raster graphic image to Vector Graphic Image is using "Trace BitMap" image. In this method the Raster image is copied on to the screen of INKSCAPE software in an embedded form. The image then undergoes multiple scans to creat a group of paths. These scans are grouped together to form a Vector Graphic Image. This image is now in SVG format.

8. The procedure for the conversion has been elaborated below:-.

(a) Open INKSCAPE Software. Go to Document Settings and convert the properties to Pixels and remove the page border. Then import the image that is required to be converted from Raster to Vector Graphics.


(b) Post importing the image, convert the view into CUSTOM View and ZOOM to 1:1 ratio. In order to convert the image into a Vector Graphic, go to "PATHS". In PATHS, select "TRACE BITMAP". This will open a dialog box to select the mode of conversion. for a color image we can go for Multiple Scans, color mode and go for a suitable scans to recreate the image accurately.


(c) The image is converted into a Vector Scan and is created right on top of the existing image. This can be shifted to a side to observe both the images. They Vector image generated can be Ungrouped. Post Ungrouping we will be able to see all the scans undertaken, they can be shifted and the different scans undertaken can be observed.


(d) The initial Raster Image used is as shown below for reference.


(e) The final Vector Raster Image developed is as shown below.


(f) The Vector Image developed can also be exported in PDF format.


9. The other methodology is to add a layer on the imported image, reduce the opacity of the embedded image and draw the curves of various lines in different layers. Each layer can be drawn using the Bezier Pen or FreeHand Pen for recreating the image. In the outline developed colour can be added as required to develop a Vector Image.

Laser Cutting

10. The vector image developed can be exported in SVG format to CORAL DRAW softwares to develop a code for laser cutting. For the purpose of this exercise the SVG format of a LOGO developed for a COCKTAIL mixer, the example shown in Methodology-I was used. The vector image of the scanned JPEG file was modified with wordings around it and a suitable logo was developed.

11. This LOGO was exported in CORAL DRAW, a boundary was given for cutting the object and a power setting of 50% and speed of 10% and frequency of laser at 50% were set for Wood and a power setting of 30%, speed of 15% and frequency of 50% was used for Acrylic boards.

12. The logo was laser cut onto a wooden board and an Acrylic Board.



13. For the purpose of 3D CAD programming a work undertaken on positioning of an Expansion Joint on the top deck of a barge was used. In this exercise a simple barge was designed in ANSYS and the weight distribution on the structure was positioned so as to give a hogging condition where the top deck is in tension. The structure develops high stresses and hence there is a requirement to add expansion joints to ensure the top deck has more flexibility for expansion and thus there is a reduction in the stresses on the structure. The exercise was undertaken for two seperate types of expansion joints and the advantages of one over the other has been identified.