Illustrator Drawing Tools, Part 5: Pen Tool – Curves

June 8, 2009

This is the final part of the series on drawing tools in Illustrator. In the last post we looked at how to use the Pen tool to draw straight line segments and how to use the Selection tools to edit entire paths and individual points. To conclude the series, today’s post is about drawing curves with the Pen. This is generally perceived to be the hardest part of using the Pen tool, but all it requires is a bit of practice and understanding of how the curves work.

Drawing curved paths

Unlike straight paths, curved paths are created by clicking and dragging. The first time you click and drag, you set a starting point for the curved path and importantly, you also determine the direction of the curve. As you continue to drag, a curved path is drawn between the previous point and the current point.

Two things happen when you click and drag with the Pen tool.

1. An anchor point is placed on the artboard when you click.

2. Direction lines and direction points are drawn when you drag.

We use the direction lines and points to determine the direction and shape of the curved path we’re drawing. Let’s start drawing.

1. Select the Pen tool from the toolbox or hit P as a shortcut.

2. Click and immediately drag the pen tool pointer upwards.

When you release the mouse button, an anchor point appears where you first clicked and two direction lines extend above and below the anchor point.

3. Continue the curve, by clicking and dragging in the opposite direction to add another point.

If you make a mistake while you’re drawing, choose Edit > Undo New Anchor Point (Ctrl +Z / Cmd + Z) to undo the last point you drew, and try again.

4. Do the same again to add another curve.

If you hold down Shift as you click and drag, you constrain the slope of the directional line to 45° increments.

5. To finish your path, just Ctrl + Click / Cmd + Click.

Drawing a closed curved path

Here’s how to draw a closed path, in this case a circle, using the Pen. Remember you always want to use as few anchor points as possible.

1. Click and drag upwards (or downwards – the direction you drag is the direction the curve will go).

2. Drag down from a new point directly opposite your starting point.

3. Close the path by positioning the pointer over your starting point and clicking and once more dragging upwards until you have the curve you want.

Combining curved and straight path segments

Now that you’ve learned how to draw straight and curved paths individually, you’ll need to be able to put them together. You’ll be combining paths that combine corner points and smooth points. Smooth anchor points have directional lines that are opposite each other, 180° apart. Corner points either have no directional lines, only one directional line, or two directional lines that are at an angle that is not 180°. ( A little bit confusing, I know!)

Probably the most difficult combinations you’ll do is joining up two curves on a corner point. If you can do this, then you can do any type of drawing with the Pen. Let’s say you want to create something that looks like this;

1. Select the Pen tool.

2. We’re starting with a straight segment, which is dead easy, so click once for your starting point (don’t drag) and the click again to put down your second anchor.

3. Now we’re going into a curve. When you move the pointer over the last anchor point, the cursor changes to show what looks like an upside down “v”. This indicates that you are going to convert the point from being a straight point to a curved point. Click and drag upwards in one motion to start the curve. Then click and drag downwards to create your next anchor point and finish the curve you started.

Now we need another curve. However you will find that if you simply click and drag a new point, it is not going to go where you want. You might get something like this;

Or something like this if you drag the opposite direction.

4. To prevent this happening, we need to start a new curve by holding down Alt / Option + Clicking on the last anchor point. You will again see the little upside down “v”. Holding down Alt/Option, drag upwards to create a second curve going up. Then click and drag your next point down to complete the curve. You should have something that looks like this;

5. Repeat step 4 to create a third “upwards” curve.

6. To finish up, we need to convert from a curved point to a straight point. Once again, hold down Alt / Option and click once on your last anchor point, release the Alt/Option key and then click again to put down your last anchor point. You should now have made a path that looks like this;

7. Ctrl / Cmd + click anywhere to complete the path.

There is, of course, lots more to learn about the Pen tool, but at this stage lots of practice combining straight segments and curves will turn you into a Pen-jockey really quickly. I will be returning to this topic in the coming weeks and will show you some tips and tricks to speed up and refine your Pen tool usage. In the meantime, a really good way to practice combining curves and straight points with the pen tool is to try drawing the outlines of letters. Start with easy ones like I and Z, then try lowercase T, S, P and so on. This is an exercise I give to my classes and they find it useful.

I hope you’ve found this series on Illustrator’s drawing tools useful.

Are you new to the pen tool? Is it something you’ve been avoiding? What other tools would you like to know more about in Illustrator?