Tool: The Pen
Why is the pen tool so hard to learn?
It’s a fair question, and the usual answer — that beziers are mathematical and people aren’t — is wrong. People handle plenty of mathematical things without noticing. The real answer is that the pen is the only tool in the toolbar where what you do and what you get are not the same gesture. You drag there and the curve moves here. Every other tool in the application is direct. The pen is remote control, and remote control takes practice.
Here’s what’s actually happening. A bezier curve is defined by its endpoints and by a handle at each end. The handle isn’t part of the drawing. It’s a lever. It points in the direction the curve leaves the anchor, and its length says how insistently the curve goes that way before it gives up and heads toward the other end. Long handle, lazy sweeping curve. Short handle, curve that snaps quickly to its destination.
So when you click and drag with the pen, you are not drawing the curve. You are setting the lever that the curve will obey. That is the entire conceptual gap, and once it closes, the pen stops being hard. It doesn’t get easier gradually. It clicks. [1]
Then there’s the second thing, which is the one that separates people who can use the pen from people who own it: you can break the handle.
By default the two handles at an anchor are locked into a straight line through it. Pull one, the other swings to stay opposite. This is what you want almost always, because it’s what makes a curve pass through the anchor smoothly instead of kinking at it. Smoothness is the default because most curves are smooth.
But a crescent moon has two points. A leaf has a tip. A heart has that notch. In each case the curve arrives at an anchor going one way and needs to leave going a completely different way, and as long as the handles are locked, that is impossible — you’ll keep trying, and the shape will keep rounding itself off, and you will conclude that the tool is fighting you.
Break the handle and the two sides become independent. The curve comes in along one and leaves along the other, and the anchor becomes a corner. That’s it. That’s the whole trick. Almost every shape that beginners can’t make is a shape that needs one broken handle. [2]
Now, having said all that, I’d like to argue against my own tool.
The pen is the primitive, and it is not usually the right thing to reach for. If you need a crescent, do not draw a crescent with the pen — draw two circles and subtract one with Shape Builder, and you’ll be done before you’ve placed your second anchor. If you have a curve that’s nearly right but sags in the middle, don’t hunt for the anchor that’s wrong; grab the region with Reshape and pull. If you want a curve to pass through three specific points, use Curvature and click the three points.
Those tools exist precisely because the pen is remote control and remote control is expensive. Each one is a way of expressing a shape in terms closer to how you actually think about it.
So what’s the pen for? It’s for when you know exactly what you want and no higher-level tool expresses it. It’s for the last five percent — the one anchor in a logo that has to sit precisely there with precisely that tangent, because you can see that it doesn’t. It’s the manual transmission. Most of your driving shouldn’t need it, and the day you need it, nothing else will do.
That’s also why it’s the tool that makes this a vector editor rather than a drawing app. Everything else in the toolbar is a convenience built on top of paths and anchors. The pen is you, touching the actual thing the document is made of, with nothing in between.
It’s mapped to P.
[1] If it hasn’t clicked yet, here is the exercise that does it faster than any explanation: draw one curve, then drag the handle around in a slow circle and watch what the curve does. Thirty seconds. The relationship becomes obvious in a way no paragraph can make it.
[2] The other one is drawing too many anchors. A curve wants the fewest anchors that can describe it — two, usually, for something like the side of a leaf. When a shape looks lumpy, it is almost always because it has fifteen anchors where it needed three, and each one is a little lump.