To draw a natural Spline or a Bézier curve, choose the Spline tool in the Toolbox and the first (natural spline) or the second (Bézier curve) Geometry Method icon in the Info Box.
Natural splines can be defined by placing nodes, which the program automatically connects, thereby generating a smooth custom curve. The angle of the tangent and the shape of the spline generated with it is affected by each subsequent node defined. You can conclude this operation by double-clicking on the last node or by clicking the OK button in the Control Box. Clicking OK always results in a closed spline.
Bézier splines are somewhat more complex in nature, but they allow more accurate reproduction of specific custom shapes. Bézier splines are defined by nodes, just like natural splines, but they also have editable tangent handles on either side of these nodes, plus one tangent handle at each end (if it is an open spline). The shape of the Bézier spline is affected by the direction of the tangent and the length of each tangent handle.
When defining Bézier splines, click once to place a node, and keep the mouse button depressed. By moving away from the node in any direction, you are in effect defining the initial tangent, and the length of the handle that defines the curvature. If you release the mouse button, ARCHICAD will assume that you wish to jump to the definition of the next node with your next click. Keep the mouse button depressed, and then define the next tangent and node as above. You can conclude this operation by double-clicking the last node or by clicking the OK button in the Control Box. Clicking OK always results in a closed spline.
You can edit Bézier splines by varying the length of each handle separately: use the pet palette command for Move tangent handle.
Note that there is only one angle associated with both handles of a node, but the length of each handle may be different. The longer the editing handle, the smoother the curve will be at the control point.
Note: The visibility of the editing handles of Bézier splines depends on the status of the View > On-Screen View Options > Spline Handles toggle. If this toggle is set to “Show,” then all editing handles are visible on the Floor Plan. If the toggle is set to “Hide”, then only the editing handles of the spline last selected will be visible; if the selection is removed, no editing handles will be visible.