Dialog: Blend-Curve

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Dialog: Blend-Curve

Blend-Curve

See also Add Blend-Curve

A Blend-Curve sketch-element has a start-Point and an end-Point.

You can use the Blend-Curve dialog-box to edit these geometric-properties AT its start-Point and AT its end-Point:

•Angle

•Curvature

•Curvature Rate  

Typically, you will merge the start-Point and/or end-Point of the Blend-Curve with another sketch-elements.

The default geometric-properties ensure geometric continuity of the Blend-Curve with the adjacent sketch-elements.

Case 0 : The Blend-Curve is not merged with another sketch-element. You can edit these geometric-properties at its start-Point and end-Point:

•Angle (default = 0)

•Curvature (default = 0)

•Curvature Rate (default = 0)

Default values

Case 1 : You merge the start-Point and/or end-Point of the Blend-Curve with a Line.

•Angle is equal to the angle of the Line

•Curvature is equal to zero

•Curvature Rate  is equal to zero

Case 2 : Merge the start-Point and/or end-Point of the Blend-Curve with an Arc.

•Angle is equal to the tangent of the Arc

•Curvature is equal to 1 / Radius of the Arc (m)

•Curvature Rate - is equal to zero

Case 3 : Merge the start-Point and/or end-Point of the Blend-Curve with a Blend-Curve.

Edit the end-Point of a Blend-Curve that you merge with the start-Point of an adjacent, or following, Blend-Curve.

In the Blend-Curve dialog-box, edit the:

•Angle : Disable the end-Point Angle check-box: edit the Angle - the angle of the adjacent Blend-Curve with equal the angle you enter.

•Curvature : Disable the end-Point Curvature check-box: edit the Curvature - the curvature of the adjacent Blend-Curve with equal the curvature you enter.

•Curvature-Rate : Disable the end-Point Curvature-Rate check-box: edit the Curvature-Rate - the curvature-rate of the adjacent Blend-Curve with equal the curvature-rate you enter.

You can edit the geometric-properties

•Exactly : with the Blend-Curve dialog-box

•Approximately : with the Blend-Curve drag-handles.

Edit Exactly

tog_minusHow to open the Blend-Point dialog-box

MD-GA-Blend-Curve-Edit

In the Part-Editor or the Mechanism-Editor:

1.Double-click the Blend-Curve in the graphic-area

OR

1.See How to Open a Dialog-Box  

The Blend-Curve dialog-box is now open.

tog_minusBlend-Curve dialog-box
MD-Dialog-Blend-Curve-Collapsed

There are two separators:

 Start-Point...

 End-Point...

The parameters are the same for the two separators.
MD-Dialog-Blend-Curve-StartPointEnd-Point

 Start Point ...  / End Point ...

Angle (Units: º):

Blend / Free check-box:

☑ (DEFAULT) The angle of the Blend-Curve (at its start-Point / end-Point) is equal to the angle of the adjacent sketch-element

❑ Edit the angle of the Blend-Curve (at its start-Point / end-Point).

Curvature k (Units:1 ∕ meter):

Blend / Free check-box:

☑(DEFAULT) The curvature of the Blend-Curve (at its start-Point / end-Point) is equal to the curvature of the adjacent sketch-element.

❑Edit the curvature for the Blend-Curve (at its start-Point / end-Point).

Curvature-Rate dk ∕ ds (Units: 1 ∕ m^2):

Blend / Free check-box:

☑ The curvature-rate of the Blend-Curve (at the start-Point / end-Point) is equal to the curvature-rate of the adjacent sketch-element

❑ (DEFAULT) Edit a curvature-rate for the Blend-Curve (at its start-Point / end-Point).

Velocity Scaling (no units)

Increase Velocity-Scaling to inflate the balloon!

Decrease Velocity-Scaling to deflate the balloon!

Velocity Scaling does not have units.

Default = 1 ; Maximum = 10 ; Minimum 0.01

Edit Approximately

tog_minusTo show / hide the Blend-Curve drag-handles
Drag handles in the Graphic-Area

Drag handles in the Graphic-Area

To show the Drag-Handles

1.Click the Blend-Curve one time

Now, you can see the Drag-Handles at the start-Point and the end-Point

There are two(2) Drag-Handle types:

Red-14-1 Arrowhead Drag-Handle

Red-14-2 Circle Drag-Handle (not easy to see)
tog_minusBlend-Curve Drag-Handles
Arrowhead Drag-Handle

Arrowhead Drag-Handle

Arrowhead Drag-Handles - this controls the Angle and the Velocity-Scaling Factor

1.Double-click an Arrowhead Drag-Handle to enable it.

The Drag-Handle should now be blue - it is enabled

2.Drag the blue arrowhead relative to the start-(or end-)Point:

Red-14-1b Rotate the arrowhead to control the angle of the Blend-Curve.

Red-14-2 Move the arrowhead away to increase the Velocity-Scaling factor

3.Double-click the Arrowhead Drag-Handles again.

The Drag-Handle should now be green - it is disabled.
Circle Drag-Handle

Circle Drag-Handle

Circle Drag-Handle - this controls the Curvature

1.Double-click a Circle Drag-Handle (not easy to see!)

The Drag-Handle should now be blue (not easy to see!) - it is enabled.

At the default position (vertically-up), the Curvature = 0 (a straight-line).

2.Rotate the blue circle around the start (or end-)Point:

Red-14-1b In a clockwise direction to increase the +ve curvature

Red-14-1b In a counter-clockwise direction to increase the –ve curvature

When the blue circle is vertically-down the Curvature is a large +ve or –ve value.

3.Double-click the Circle Drag-Handle again.

The Drag-Handle should now be green - it is disabled.

Note on Curvature and Curvature-Rate

tog_minusCurvature and Curvature-Rate

Curvature (k) = 1 / Radius of Curvature

The Radius-of-Curvature and the Curvature of a simple sketch-elements is constant. For example:

•Radius of Curvature of a Line = ∞, Curvature of a Line = 0

•Radius of Curvature of an Arc or Circle = Radius, Curvature of a Circle = 1 ∕ Circle Radius,

E.g. : A circle has a radius of 20mm, its curvature = 1/0.02m = 50/m.

However, the Radius-of-Curvature continually changes along a general curve.

Thus, the Curvature will also continually change along a general curve.

Curvature-Rate =  dk/ds

Curvature-Rate = rate-of-change of curvature (k) with respect to the displacement (s) along the curve.