CAD Drawing

This article introduces CAD objects in NUBIGON and describes how to draw them.

There are five types of CAD objects in NUBIGON; these are polyline, arc, circle, point, and compound curve.

Start & Cancel Drawing

There are two ways to activate the drawing of a CAD object:

  • Press & hold the keyboard shortcut of the object type to be drawn. Release the shortcut key to cancel the drawing.
  • Click the relevant icon on the Toolbar (or the command in the Tools > CAD menu). To cancel the drawing, click the icon (or the menu command) again or press the Esc key.
TIP: Navigation is not possible when a drawing mode is active.

2D Drawing vs. Free Drawing

2D: Click  on the Actionbar to enable snapping to cross-section plane. In this case, all drawing actions will be performed on the main-section plane (as defined in the first tab of the cross-section window).

3D: Disable snapping to cross-section plane to draw directly on the viewport.


Tools > CAD > Polyline
(Shortcut: Press & hold X)

  • Create: Adding the first two vertices will create a new polyline. We distinguish between 2D and 3D polylines. To create a 2D polyline, enable 2D drawing as described above. All subsequent dragging operations on a 2D polyline will be performed on the polyline’s supporting plane.
  • Extend: To add vertices to an existing polyline, select that polyline before starting to draw.
  • Close: To create a closed polyline, first, turn on snapping to CAD from the Actionbar. Then while drawing, move your cursor to the first vertex of the polyline, and when you see the yellow highlight on the vertex, left-click.


Tools > CAD > Arc
(Shortcut: Press & hold V)

The Arc tool is used to create a new arc by defining the start point, endpoint, and middle point of the arc.


Tools > CAD > Circle
(Shortcut: Press & hold B)

There are two methods to create a new circle. Once circle drawing is activated, you can choose the desired method in the Tool window:

  • Three points: Use left-click to define three points on the circle.
  • Center and radius: Left-click to set the center point. Drag the mouse and release the left mouse button to define the radius.


Tools > CAD > Point
(Shortcut: Press & hold P)

Once activated, left-click to add a new point.

Compound Curve

Tools > CAD > Join

A compound curve is a sequence of polylines and arcs that touch end to end. To create a compound curve, select polylines and arcs, and click the Join icon or select Tools > CAD > Join.

We distinguish between 2D and 3D compound curves. Joining 2D curves that lie on the same plane will create a 2D compound curve.

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