Create Spline
The Spline object allows you to quickly create new splines from scratch. However, for some shapes this approach can be clumsy and unnecessary. For this reason CINEMA 4D includes spline curves. These are interactive tools that remain active until you select another tool, such as Move. You can thus create any number of these splines without the need to select the command each time.
When drawn in a 3D camera view (Perspective, Parallel, Military, Frog, Bird, Gentlemen, Isometric, and Dimetric), all spline curve tools other than the Freehand spline curve tool draw spline curves in the XZ plane. When drawn in a 2D camera view (Left, Right, Front, Back, Top, Bottom), all spline curve tools draw spline curves in the facing plane.
You can use this command to draw curves directly in the viewports.
Select the Freehand tool, then click in a viewport and keep the mouse button pressed. You can then draw the Freehand curve for as long as the mouse button is held down. Releasing the mouse button will end the Freehand spline creation and the finished spline will appear. (This is especially useful when tracing patterns with a graphics tablet.)
To add further vertices, Ctrl-click in the viewport. Keep in mind, however, that the vertices will now be placed onto the XZ plane.
If the start and end positions of the finished curve are positioned close together, the curve is automatically closed.
Tolerance
This value defines how accurately the spline curve follows the mouse movements. The higher the Tolerance value, the more rounded the spline will be and the fewer vertices will be generated.
Using these commands, you can create the exact type of curve you require. Choose the desired spline type. Point editing mode is activated automatically. Click to create each point. Once you’ve added the desired points, either click the starting point to close the curve or press Esc to exit the mode. You can then edit the spline in the usual way (drag to move a point; Ctrl-click to create a new point, etc.).
If you work in the 3D viewport, the spline is created in the XZ plane. Then it is not possible to set vertices above the horizon.