Area Setup

Your area is the real-world space the circuit has to fit inside — a table, a garage floor, a hall. You set it in the New Circuit wizard, before you place a single piece, because Auto Fix and every clearance check need it as a starting point rather than an afterthought.

Box or custom shape

The wizard’s Area shape toggle offers two ways to define it. Box is a plain rectangle — type its length and width right there in the wizard, in whichever unit system you’re using, and the circuit is created immediately. Custom hands you off to the canvas: click to place each corner, type its exact real-world edge length in the popup that appears, and click back near the start to close the shape once you have at least three corners.

The two aren’t equally flexible later. A box’s length and width stay editable for the life of the circuit. A custom-drawn boundary doesn’t — reshaping it isn’t supported, and the only way to change one is to start a new circuit and redraw it. If you think you’ll want to adjust the footprint as you go, Box is the safer choice.

Auto Fix

Set your area first, and anything you draw is checked against it: a piece that ends up outside the boundary is flagged in the guidance panel, the same place lane-width and grade warnings show up. When Circuit Builder can actually resolve what’s flagged, an Auto fix button appears there — click it and the circuit is moved, rotated, or otherwise nudged back inside the area in one step, one undo. It doesn’t run on its own; you decide when to press it.

Changing the area later

For a box area, click either dimension label on the boundary itself, right there on the canvas, to type a new length or width. A custom-drawn area can't be reshaped this way — start a new circuit and redraw it if the footprint needs to change. See Scale & Units for how the RC scale you pick alongside your area affects what fits inside it.