Draw a Circle
Thu, 2009/10/01 - 18:17 — admin
- Start Drawmetry and enter "Insert Point" mode by clicking on the "Insert point" button, which has an arrow over a small green square. Hovering over a button brings up a tool tip telling you when your cursor is over the "Insert point" button.
- Double-click in two different place on the canvas. This inserts two point variables each marked with a green dot. When a point variable is selected the dot turns into a small square.
- Single-click on the canvas or click the Default mode button on the Drawing tool bar to enter Default mode. In Default mode, click on one of he point variables. Observe that the dot turns into a small square and the name of the point variable displays at the left in the feedback bar, which is below the canvas. The name should be P_0 or P_1. Select P_1, click in the constraint field above the canvas and type: "=distance(P_0,180)". (Do not include the quotation marks, only what is between the quotation marks.) Instead of typing "P_0" you can simply click on P_0, which inserts "P_0" at the text cursor position. Press Enter or Return when done. The point variable P_1's marker should move to a distance of 180 points (= 2.5 inches) from P_0 and turn into a yellow dot.
- Try dragging P_1 in a circle around P_0. Observe that P_1 stays at a constant distance from P_0 but, otherwise, it follows the cursor. On the Tools menu, select Trace On. Select P_1 by clicking on it. Then drag it slowly one full revolution around P_0. Avoid going back and forth and release the mouse button as closely as possible to the start of the curve.
- Un-select Trace On from the Tools menu to turn tracing off. Click on the circle you just made to select it. Notice a light gray rectangle around the circle. While the circle is selected, type in the constraint field: "=anchor(P_0, P_1)" and press Enter or Return. Click on the circle again to select it. The bounding rectangle should be pink to indicate that the circle is anchored. Drag P_0 (i.e., the center of the circle) and observe that the circle follows. Remove the constraint from P_1 by selecting P_1 and then deleting the text in the constraint field and pressing Enter/Return. Drag P_1 and observe that the radius increases or decreases.
- Save your work using Save or Save As... from the File menu or clicking on the Save button on the File tool bar. Save the drawing to a file named "circle_1.svg" into a folder named "Basic Shapes".