Useful first: Draw your first rectangle
Every point on a circle is the same distance from its centre. That distance is the radius; the diameter is twice as large. A circle encloses a region that can be used in modelling and CAM.
Try it in Cadivari
Place the centre
In a Top-plane sketch, press C or choose Circle. Click once for the centre and move outward to preview the circle.
Set the initial size
Read the radius and diameter in the live preview. Click a second time to create the complete circle. There is no need to drag around its circumference.
Enter an exact radius
Press V and click the circle’s outline. In Properties, set R to 58 mm. Confirm that D becomes 116 mm. CX and CY set the centre position.
Compare the two handles
Drag the dashed centre handle to move the circle without resizing it. Drag the solid handle on its right edge to change the radius. Undo each experiment to restore the 58 mm radius.
A small exercise
Create a circle with R = 58 mm. Change D to 100 mm and check R, then undo to return to the original size.
What you should see
R becomes 50 mm when D is 100 mm. Undo restores R = 58 mm and D = 116 mm without moving the centre.
Things to look out for
- Select a circle by its outline. Clicking its interior does not select it.
- Existing circle centres and quadrants are not snapping targets yet. Use Properties for exact centre coordinates.
Check your understandingWhat happens to the radius when you double the diameter
The radius doubles too. Cadivari keeps R and D synchronized, with D always equal to twice R.
With JavaScript enabled, you can save lesson completion in this browser.
Go deeper in the knowledge base
Instructions checked against the Cadivari 0.3.0 source and knowledge base on 2026-09-16. Lesson revision 1.