You'll need: FontCreator (Windows and macOS), and a glyph to draw or clean up.

Good outlines are the foundation of a good font — they interpolate cleanly, hint better, and render sharper at small sizes. The difference between a messy outline and a clean one is rarely talent; it's a handful of habits and knowing which on-screen aids to switch on. This guide covers both.

What a clean outline looks like

Before the tools, the targets. A well-drawn contour:

• Uses as few points as possible. Every extra on-curve point is something that can drift out of line. If you can describe a curve with two points, don't use four.
• Puts on-curve points at the extremes — the top, bottom, left and right of each curve. Extreme points keep curves predictable, help hinting, and are required for clean interpolation in variable fonts.
• Has smooth tangents where a curve should flow, and a deliberate corner only where you actually want one.
• Runs in a consistent direction — outer contours one way, inner counters the other — so fills and counters render correctly.
• Has sensible start points, which matters as soon as you interpolate across masters.

The rest of this page is about the FontCreator features that make hitting those targets easy.

the same lowercase o drawn with too many points vs. four points at the extremes

Know your points: corners vs smooth

In Point mode FontCreator shows you, at a glance, what every node is:

• Rectangles are on-curve corner points — the path can change direction abruptly here.
• Large green circles are on-curve smooth points — the curve flows through them without a kink.
• Small circles are off-curve points, also called handles or control points.

Knowing which is which is half the battle: a point that looks like it should be smooth but is drawn as a corner (a rectangle) is usually the cause of a lump you can't quite see. The commands below turn corners into smooth points for you.

See the curve: the curvature comb

Turn on View → Show Curvature Comb. It draws a comb of lines along each curve whose length reflects curvature — so a smooth curve shows an even, flowing comb, and a kink or a flat spot jumps out as an abrupt change. It's the fastest way to catch the bumps your eye glosses over.

Tip: Watch the comb as you drag a handle. When the teeth fan out evenly, the curve is smooth; a sudden spike means a point or handle is fighting the curve.

Check direction: contour-direction arrows

View → Show Contour Direction (on by default) draws an arrow at each contour's start point showing which way it runs. If a counter is filling in solid, or an interpolation looks wrong, this is the first thing to check — a reversed contour is a common culprit. Fix one with Glyph → Change Direction.

Draw precisely: the Pen Tool, snapping and zoom

• Hold Shift while placing points to constrain to 45° steps — horizontal, vertical and the diagonals — so stems and flat sections stay true.
• Snap to grid and guidelines pulls points and contours onto the grid and your guidelines as you move them, which keeps related edges aligned. Need to place something just off a guide? Hold Alt while dragging to ignore snapping for that move.
• Marquee zoom: press Ctrl+Space and drag a rectangle to zoom into exactly the area you want; hold Alt while dragging to zoom out. Far quicker than stepping through zoom levels when you're chasing a single node.
• New contours are created closed by default — you don't click back onto the first point to close them. Finish a contour with Apply (or Enter).

Edit cleanly: the delete keys

The two delete keys do different jobs, and mixing them up is a classic source of mangled curves:

• Backspace removes the selected on-curve point with a smart delete — it keeps the surrounding curve shape rather than leaving a dent.
• Shift+Delete breaks the contour at the selected point (it splits it open); it does not delete the point.

Watch out: if a contour suddenly opens up when you meant to remove a point, you pressed Shift+Delete. Use Backspace to delete points.

Make curves flow: Smooth Curves and Smooth and Align Curves

A curve is only truly smooth when its on-curve point sits exactly on the straight line between the two off-curve handles on either side. Nudging that by hand is fiddly, so FontCreator has two commands to do it for you. Select one or more on-curve points (each surrounded by off-curve points), right-click, and choose:

• Smooth Curves (access key S) repositions the on-curve point onto the line between its handles so the curve flows through it without a kink. It only acts on points that are already close to smooth, so it tidies rather than reshapes. With nothing selected, it applies to every eligible point in the glyph.
• Smooth and Align Curves (access key D) does the same and additionally aligns the surrounding points — handy for straightening a tangent and cleaning up a node in one step.

Editing handles by hand: while moving selected points, Ctrl+Shift asks FontCreator to keep the curves smooth, and Ctrl+Alt makes them symmetrical. Hold Ctrl alone to override FontCreator's automatic smoothing and move a handle freely.

Reduce points automatically: Optimize Contours

Deleting points one at a time with Backspace is right when you're fine-tuning, but it's slow when an outline has far too many points — which is common after importing or tracing artwork. For that, let FontCreator do the work: Optimize Contours reduces the number of points that make up a contour while keeping its shape.

• Run it from Glyph → Optimize Contours, or click the Optimize Contours icon in the toolbar at the top of the glyph editor.
• It works on both quadratic (TrueType) and cubic (PostScript/CFF) curves.
• For a whole font, run it as a Transform script across the selected glyphs — ideal for cleaning up a freshly imported or traced typeface in one pass.

Because Optimize Contours can shift the outline slightly as it removes points, check the result with the curvature comb and use undo/redo to compare against the original. It also works best on closed contours; for open contours (such as single-line designs) tidy the first point by hand if needed. Try it on a copy of a glyph first to get a feel for how aggressively it simplifies.

Related: to switch a contour between curve types — quadratic to cubic or back — select it, right-click and choose Convert. FontCreator lets you draw in either curve type and decide the outline format at export; see TrueType vs PostScript: TTF, OTF & Curve Formats.

A quick cleanup pass

A reliable routine for tidying any outline:

1. Turn on the curvature comb and contour-direction arrows.
2. Remove redundant points until the comb still reads smooth with fewer nodes — by hand with Backspace, or with Glyph → Optimize Contours to reduce points across a whole contour at once, then recheck the comb.
3. Make sure there's an on-curve point at each extreme.
4. Run Smooth Curves (S) on points that should flow, so each smooth node sits between its handles.
5. Confirm every contour runs the right direction; flip any that don't with Change Direction.
6. Zoom in on each corner and junction with Ctrl+Space and check the comb for kinks.

Troubleshooting

Frequently asked questions

Why should I put points at the extremes of a curve? Extreme points (top, bottom, left, right) keep curves predictable, improve hinting at small sizes, and are needed for clean interpolation between masters in a variable font.

How do I see whether a curve is smooth? Turn on View → Show Curvature Comb. An even, flowing comb means a smooth curve; an abrupt change in the comb's length marks a kink or flat spot. In Point mode you can also tell node types apart: rectangles are corner points, large green circles are smooth points, and small circles are off-curve handles.

My counter is filled in — what's wrong? The contour is almost certainly running the wrong direction. Switch on View → Show Contour Direction to confirm, then use Glyph → Change Direction on the offending contour.

What's the difference between Backspace and Shift+Delete? Backspace deletes the selected point while preserving the curve shape. Shift+Delete breaks (splits) the contour open at that point — it doesn't delete it.

What do Smooth Curves and Smooth and Align Curves do? Both make a curve flow through its on-curve point by placing that point on the line between its two handles. Smooth Curves (S) just smooths; Smooth and Align Curves (D) also aligns the surrounding points. Right-click selected on-curve points to use them.

How do I quickly reduce the number of points in an outline? Use Glyph → Optimize Contours (or the toolbar icon), or run it as a Transform script to clean up many glyphs at once. It works on both quadratic and cubic curves and can shift the outline slightly, so compare the result with the curvature comb.

What to read next

• Creating a Font and Editing Glyphs — the basics of drawing and editing your first glyphs.
• Import Vector Artwork (SVG, EPS, AI) — bring in vector paths, then clean them up with the habits above.
• TrueType vs PostScript: TTF, OTF & Curve Formats — quadratic vs cubic curves and the Convert command.
• Reusable Corners, Serifs & Caps (Path Decorations) — add designed corners and serifs without hand-drawing each one.