3D Spline

Task area 3D Objects

You can use this tool to draw open and closed B-splines and cubic splines.

Note: You can show or hide control points of B-splines using Show/Hide.

To draw a 3D spline

1. Click 3D Spline (How).
   

   Activate 3D Spline in one of the following ways

   • Actionbar:Role Draft Task Modeling Task area 3D Objects

   • Menu bar: Create Bonus Tools 3D Modeling

   • Palette: Tools Create area in the following module(s):

   3D Modeling

2. Select the spline type:
   • B-spline from control points
     Example
   • B-spline from interpolated points
     Example
   • Cubic spline
     Example

     Tip: You can change the spline type while drawing the spline. The selected spline type applies to the spline as a whole.

3. Define more parameters for the 3D spline:
   • Degree (B-splines only):
     Define the degree for calculating the segments of the 3D spline (1 to 10). The greater the degree, the smoother the spline. Degree 3 is set by default; Degree 3 or Degree 4 is usually sufficient. You need to increase this value when you import data from Rhino, for example. Degree 1 produces a polygon. The number of control points defines the maximum value for Degree.
   • Closed:
     The program automatically connects the last point and first point you entered, thus producing a closed 3D spline.
4. Define the input mode:
   • Custom
     Click to enter any control points of the 3D spline. You can even click points on existing elements.
   • Match points from element
     You can enter the control points of the 3D spline freely. If you click an existing element (for example, a 3D polyline), the program uses all points of this element as control points.
   • Match terrain points
     You can use terrain points as control points of the 3D spline. You can select these terrain points by clicking them or by enclosing them in a selection rectangle. For example, this option is useful for road location lines.
5. Set the start point of the 3D spline by clicking a corner or end point of a solid or line.
6. To set more points of the 3D spline, do the following:
   • Click a corner or end point of a solid or line.
   • Enter the dX, dY and dZ vectors.

     Tip: Click Back to undo as many steps as you want.

7. Press ESC to finish.

   Note: The start and end points of a line can be positioned so that they are parallel to the coordinate planes (elevation, plan). The points automatically assume the coordinates of the coordinate plane that is parallel to the screen.

   Tip: Point snap or Work Plane (How) help you draw 3D splines without existing 3D elements.

   

   Activate Work Plane in one of the following ways

   • Actionbar:Task area Work Environment

   • Menu bar: View

Tip:Editing 3D splines