Science PowerPoint tips and tutorials

Among simple drawing tools that are available in PowerPoint, Curve Tool is especially useful for drawing curved lines, arrows and irregular closed objects. Because of its general utility, it should be always available for immediate action in bottom toolbar in PowerPoint as a separate button. Refer to Essential Drawing Tools I and Setting up Your Personal Workspace previous articles for more information on how to place this tools icon in the bottom drawing bar.

In contrast to Freeform and Scribble tools, which also allow drawing curved lines and objects, the Curve tool lets you draw them in a more elegant way. By definition, line fragments (segments) between edit points are curved and this allows you to connect separate objects on the slide in a more creative way. Once the curved line or arrow is finished, using Edit Points dialog box, as we will show later, you can change the line curvature, make some segments within the curved line straight and other curved. Drawing curved lines and arrows is particularly useful when making a molecular biology signaling pathway slide. Here we demonstrate how to draw a simple curved line and arrow consisting of two segments (three editing points).

Drawing curved line. First, click the Curve tool or select Curve from the lines menu in AutoShapes dialog box. Your mouse pointer within the slide area will change into crosshair. Place this new pointer where you want to start drawing a line or arrow and your first click will initiate the process. Drag the pointer to place where you want the line or arrow to make a turn and click again. Note that during drawing the first segment of the line is shown straight. Continue dragging to the point where your want the line to end and double click to end the drawing process. The whole procedure is shown in Figure 35.

Figure 35. Steps to drawing curved line/arrow using Curve tool. Note that the shown line has three editing points: beginning, turn and the end.

An example of practical application for the use of curved arrow is shown in Fig. 36. As mentioned before, signaling pathways are a collection of objects and arrows and the use of curved arrows is sometimes essential. As a rule of thumb when using curved arrows: use as few editing points as possible. The arrow shown in Fig. 36 has only 3 editing points. The more editing points you will use the more difficult is to maintain smooth curves.

Figure 36. Curved arrow in the context of signaling pathway.

Editing curved lines. After you created a curved line or an arrow you can easily edit and change its properties using either Format AutoShape or Edit Points dialog boxes. Make sure that the line you are about to edit is highlighted – otherwise the corresponding dialog box will not be accessible. With the Format AutoShape dialog box (accessible from Format pull down menu and selecting Colors and Lines tab) you can change the position and shape of arrowheads (and thus transform a simple line into an arrow or double sided arrow), change the thickness and color of line and the line style (dashed or continuous). The Format AutoShape dialog box is shown in Figure 37.

Figure 37. Format AutoShape dialog box for editing lines and arrows.

Alternatively, you can have all these frequently used menus, such as line thickness, dashed lines or arrow lines arranged in the bottom Drawing bar for instantaneous access. Refer to “Essential Drawing Tools I” and “Setting up Your Personal Workspace” previous articles for more information on how to place these menus icons in the bottom Drawing bar.

More specific properties of curved line or arrow could be controlled with Edit Points dialog box tools. These can be accessed by highlighting the line you want to edit and clicking the right mouse button. From the list of general object editing tools (Fig. 38a) select the Edit Points command which will lead you to curved line editing mode. Note the end points of line to change from empty circles to closed black rectangles. The mouse pointer, when crossing the selected line of interest, changes now to a crosshair with black rectangle in the middle. Click the line again and Edit Points dialog box will appear as shown in Fig. 38b. Using tools from this dialog box you can change the line segment from straight to curved, closed path to make an object out of the curved line, add or delete points.

Figure 38. a) General line editing tools and b) Edit Points dialog box for editing curved lines and arrows.

A similar but somewhat different dialog box appears when you point the crosshair pointer to the editable point within the line. The pointer changes its shape again and if you click right mouse button Edit Points dialog box for points will appear as shown in Fig. 39. More about these tools in the upcoming article.

Figure 39. Edit Points dialog box for editing points in curved lines and arrows.

Hint: When drawing a number of similar lines on a slide, which you would like to have the same line properties (color, thickness etc.), point to the line which you would like to set as a default and click the right mouse button. From the menu (Fig. 38a) select the Set AutoShape Defaults. From now on, in this particular set of slides you are working on, each line or arrow will have the same properties.