Spline

Create a spline curve by defining the curve's starting point, end point, and a number of passing points to calculate its curvature.

Drawing Steps

1. Click to open the spline curve command.

2. In the graph area, click the first point to determine the starting point of the spline curve.
3. After you click on the viewport to create two points, start previewing the spline curve.
4. Click one by one in the viewport to draw the passing point of the spline curve.

5. You can create a spline by clicking Create, right-clicking, or double-left-clicking at the end point.

• Double left click and the spline curve will pass through the last double-clicked point.

• Right-click and the spline curve will not pass through the last right-clicked point.

6. Drag the control handles on the Spline to modify the curve shape.
7. End the command by the ESC key, or by right-clicking 【Exit Spline】from the menu, or by "Close" from the command bar.

Attribute Box

1. Left click on the spline curve in the viewport to display its properties, as shown in the image below.

• Add Constraint: Displays available constraints. Click to add the constraint to the selected element.

• Reference Line: Controls whether the current element is set as a reference line.

• Index: Displays which point on the curve corresponds to the current parameter. Click the left/right arrows to switch points.

• Coordinates X, Y: Displays the coordinates of the current point.

• Tangent Weight 1, 2: Displays the weights of the control handles on both sides of the current point.

• Tangent Radial Direction: Displays the direction of the current point's control handle.

• Tangent Drive: Check this option to manually set the control handle direction in the dialog box. Dragging other control handles will not affect this handle's direction. This option is automatically checked when dragging control handles in the viewport.

Curve Control Handle Description:

1. Circular Control Handle: Drag to adjust the handle's length and direction.

2. Triangular Control Handle: Drag to adjust the handle's length without changing direction.

3. Diamond-shaped Control Handle: Drag to adjust the handle's direction without changing length.

Note 1: Selecting the curve displays all control handles on it. Deselecting the curve hides unadjusted control handles.

Note 2: Hold the Alt key while dragging a control handle to move the handles on both sides synchronously.

Note 3: Gray control handles indicate an inactive state (i.e., not manually adjusted). Blue control handles indicate an active state (i.e., manually adjusted).