How to Draw Circles in BricsCAD

Last updated: July 20, 2026. Verified against Octave’s official V26 documentation.

Quick answer: The default way to draw a circle is by specifying a centre point and a radius, but five other methods are also built into the command. A separate Express Tools command, AI_CIRCTAN, can draw a circle tangent to three existing entities at once.

Finding the Circle Tool

The Draw menu, the Draw toolbar, the Draw ribbon panel, or the Draw tab of the No Selection Quad. Alternate creation methods specifically live in the Circle submenu of the Draw menu and on the Circles toolbar.

Drawing a Circle: General Procedure

1. Launch CIRCLE. You’re prompted to select the centre, or choose one of five alternate methods: 2 Point, 3 Point, Tangent-Tangent-Radius, turn Arc into circle, or Multiple circles.
2. Specify a point (or follow your chosen alternate method). You’re prompted for a radius, or to switch to diameter instead.
3. Either press Enter to accept the current radius, type a new one and press Enter, or click to define it graphically.

Drawing a Circle Tangent to Three Entities

AI_CIRCTAN (an Express Tools command) creates a circle tangent to three entities you select. Lines, arcs, circles, polyline segments, xlines, and rays are all accepted.

1. Launch AI_CIRCTAN. You’re prompted for the first tangent entity.
2. Click a linear entity. You’re prompted for the second.
3. Click a second entity. You’re prompted for the third.
4. Click a third entity. A circle tangent to all three is created.

Editing a Circle

1. Select the circle; its properties appear in the Properties panel.
2. Type a new value into the Center, Radius, Diameter, Circumference, or Area field and press Enter, any of these five fields can be edited directly.
3. Press Esc to stop editing.

Frequently Asked Questions

What alternate methods does the CIRCLE command offer besides centre and radius? Five: 2 Point, 3 Point, Tangent-Tangent-Radius, turn Arc into circle, and Multiple circles.

Can I create a circle tangent to three existing lines at once? Yes, using AI_CIRCTAN, an Express Tools command that accepts lines, arcs, circles, polyline segments, xlines, or rays as the three tangent entities.

Can I resize a circle by typing its area instead of its radius? Yes, the Area field in the Properties panel is directly editable, along with Center, Radius, Diameter, and Circumference.

Is AI_CIRCTAN a standard command or something extra? It’s part of Express Tools, a separate set of commands from BricsCAD’s core toolset. Whether Express Tools are included depends on your setup, if the command isn’t available, that’s worth checking.