Curve connect condition

The curve connect condition is an additional dialog (Condition) in Create Spline, Create Line, Create Arc, and Modify Spline commands. The curve connect condition defines the start point, the tangent direction and weight, and the start and end conditions of curves with respect to other edges and faces. These connect conditions can be
Tangential or curvature continuous condition.

Directions for Start/End Condition: Edge

1. Specify a Start or End Condition for a curve. The Condition sub-dialog is activated.

◦ Edge: The connect condition is defined at the start or end point of the reference edge.

The tangent or curvature value defined at the specified point of the selected element will define the tangent or curvature of the curve to be created or modified.

2. Select an edge.

3. Specify the connect condition to be Tangential or Curv Cont (curvature continuous). The feedback pointer changes color according to the connect condition: blue for tangent; orange for curvature continuous.

4. When creating an arc, you can flip the position or direction of the tangent with Flip Pos or Flip Dir.

5. Click Accept to continue.

6. Finish the 3D curve command.

Directions for Start/End Condition: Face

1. Specify a Start or End Condition for a curve. The Condition sub-dialog is activated.

◦ Face - The connect condition is defined at one of three places: a point within the face; a point on the boundary of the face; or, a point at a vertex of the face.

The tangent or curvature value defined at the specified point of the selected element will define the tangent or curvature of the curve to be created or modified.

2. Select a face.

3. Pick a point on the face: within the face, on the boundary, or at the vertex.

4. Specify the connect condition to be Tangential or Curv Cont (curvature continuous). The feedback pointer changes color according to the connect condition: blue for tangent; orange for curvature continuous.

5. If you've selected a point on the boundary of the face, define a tangent direction by choosing In, Out, or Free.

6. If you've selected a point at the vertex of a face, you can select Alt Edge.

7. Click Tangent. Use the
Vector 3D CoPilot to change the tangent length and weight. Immediate feedback of the tangent influence on the curve shape is displayed.

8. Click Accept to continue.

9. Finish the 3D curve command.

Options in Tangent Specification

• Flip Pos: Switch to the other side of the selected edge.

• Flip Dir: Switch the direction of the tangent.

• Tan Length: Specify the weight of the tangent. The weight (length) defines the influence of the tangent on the curve so that the greater the length, the greater the influence of the tangent on the curve.

• In: (The option is available if you've clicked on a face boundary.) Define the end of a curve. The inward tangent is the tangent at a given point on the face, orthogonal to the tangent of the boundary edge at a given point, and that points into the face.

• Out: (The option is available if you've clicked on a face boundary.) Define the start of a curve. The outward tangent is the negative inward tangent.

• Free: Click Tangent and the Vector 3D CoPilot appears on the face at the specified point. The tangent direction can be defined within the tangent plane at the given point on the face.

• Alt Edge (Alternative Edge): When the specified point is on a vertex of the face, you can switch between the boundary edges of the selected face to define the inward or outward tangent of these edges.