# The Facts About SketchUp Model Faces

Faces are surfaces. If you think of SketchUp models as being made of toothpicks and paper (which they kind of are), faces are basically the paper. Here’s what you need to know about them:

## 1You can’t have faces without edges.

To have a face, you need to have at least three *coplanar* (on the same plane) edges that form a loop. In other words, a face is defined by the edges that surround it, and those edges all have to be on the same, flat *plane.*

Because you need at least three straight lines to make a closed shape, faces must have at least three sides. There’s no limit to the number of sides a SketchUp face can have, though.

The figure shows what happens when you get rid of an edge that defines one or more faces. Starting with the model on the left, delete the edge that completes both the top face and one of the side faces.

The result, shown in the right, is that both of those faces disappeared.

## 2Faces are always flat.

In SketchUp, even surfaces that look curved are made up of multiple, flat faces. In the model shown, you can see that what looks like organically shaped surfaces (on the left) are really just lots of smaller faces (on the right). To make a bunch of flat faces look like one big, curvy surface, the edges between them are *smoothed*.

## 3Just like edges, faces don’t have any thickness.

If faces are a lot like pieces of paper, they’re *infinitely thin* pieces of paper — they don’t have any thickness. To make a thick surface (say, a 6-inch-thick wall), you need to use two faces side by side.