1. Choose the Create Rectangle tool.
2. Press hold and drag the cursor to create a rectangle. which is the same width as the workplane bounding box and to just under half way up the workplane. Release the mouse button to finish creating the rectangle.
3. Choose the Constrain Separation tool
4. Move over a side of the rectangle (The selected line goes light blue)
5. Select the line by clicking the left mouse button. (The line turns red)
6. Select the opposite line, press, hold and drag the cursor to create the constraint outside the rectangle
7. Repeat on the other two lines that make up the rectangle
8. Double-click the left mouse button on the constraint to open the Properties dialogue window.
9. Enter a length of 220mm and repeat for the other constraint to make the width 95mm
10. Choose the Create Circle tool
11. Using the origin as the centre drag out a circle.
12. Double click on the circle to bring up the Properties box
13. In the dialogue box enter the radius dimension as 90mm
14. Choose the Delete Line Segment tool
15. Select the unwanted portions of the lines to delete them, so producing the outline of the casing (Remember that if the wrong segment is deleted use Edit and Undo Delete)
16. Go to File menu and Save use the name ‘casing’
17. Go to File menu again and select Save Copy As.. and re-save as ‘back’.

Fig 3.

1. Choose the Select Lines tool from the Part menu and drag a box over all of the drawing. (the lines will turn red when selected)
2. From the View menu choose Isometric
3. Choose the Extrude Profile tool
4. In the dialogue box enter a distance of 100mm, check the Add material and Below workplane
5. Select OK.