Most tracing focuses on the outline—the edge where the subject meets the background. But an outline only gives you a silhouette. To draw form that feels solid, you need to describe how the surface turns in space. That's where cross-contours come in.
Cross-contour lines are imaginary lines that wrap around a form, like the wires on a 3D model. They describe the topography of the surface—where it bulges, dips, or flattens. Unlike outlines, which are flat, cross-contours give you the illusion of three dimensions. When you trace them from a reference, you're not copying edges; you're mapping volume.
Tracing cross-contours forces you to see the subject as a series of interlocking shapes rather than a flat cutout. It slows you down and makes you consider how light falls across the form. This practice builds your ability to draw from imagination because you internalize the way forms turn. It's a bridge between copying and constructing.
Start with a photo of a simple object—a mug, an apple, or a draped cloth. Using a tracing app like EchoDraw, overlay the reference on your paper. Instead of tracing the outline, draw lines that curve around the form, following its surface. Imagine slicing the object like a loaf of bread: each slice is a cross-contour. Draw those slices.
Do this for several objects. You'll start to see cross-contours everywhere.
The biggest mistake is drawing cross-contours as flat arcs instead of curves that wrap. To avoid this, imagine the lines continuing around the back of the form. Another mistake is spacing lines too far apart—this loses the sense of volume. Keep them close enough to describe the surface, but not so close that you lose the big shape.
Cross-contours are the skeleton of form. Trace them, and you'll never see a flat shape again.
Once you've traced cross-contours from reference, try drawing them from life. Set up a simple still life and draw the cross-contours you see. Then, when you draw from imagination, you can call on this mental model. Cross-contours also help with shading: they show you where the form turns away from the light.
Spend ten minutes a day tracing cross-contours from a reference. Use a different object each day. After a week, you'll notice your drawings have more depth. This is a foundational skill that pays off in every subject.
So next time you trace, don't just trace the outline. Trace the form around the corner.
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