Dialog: Blend-Curve

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Dialog: Blend-Curve

Blend-Curve

See also Add Blend-Curve

About the Blend-Curve

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

Use the Blend-Curve dialog to edit geometric-properties AT its start-Point and AT its end-Point. The properties you can edit are its:

•Angle

•Curvature

•Curvature Rate

•Velocity Scaling - a parameter that influences the overall shape between the start-Point and end-Point.

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

The default geometric-properties make sure that the Blend-Curve has geometric continuity with adjacent sketch-elements.

Case 0 : You do NOT merge the Blend-Curve 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)

Case 1 : You do 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 : You do 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 : You do 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, 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

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

Edit Exactly

tog_minusOpen the Blend-Point dialog

MD-GA-Blend-Curve-Edit

In the Part-Editor or the Mechanism-Editor:

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

OR

1.See How to Open a dialog

The Blend-Curve dialog is now open.
tog_minusBlend-Curve dialog
Blend-Curve dialog

Blend-Curve dialog

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_minusEnable / disable 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.

When the Drag-Handle is blue, it is enabled.

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

Red-14-1b Rotate the arrowhead about the start-Point (or end-Point) to control the angle of the Blend-Curve.

Red-14-2 Move the arrowhead away from the start-Point (or end-Point) to increase the Velocity-Scaling factor

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

When the Drag-Handle is 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!)

When the Drag-Handle is blue (not easy to see!), it is enabled.

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

2.Drag 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 is now green. You cannot drag the handle.

Note on Curvature and Curvature-Rate

tog_minusCurvature and Curvature-Rate

Curvature (k) ; the inverse of Radius-of-Curvature (R);

The Radius-of-Curvature and Curvature of simple sketch-elements are 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 ∕ Radius

To add numbers:

•A Circle of Radius = R20mm : Radius-of-Curvature=20mm, Curvature =1/0.02m = 50/m.

Curvature-Rate = dk/ds

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

The Radius-of-Curvature and Curvature of a simple sketch-elements (Lines and Circle/Arcs) are constant

The Radius-of-Curvature and Curvature of general sketch-elements, typically a named curve, e.g. Splines, Bezier-Curves, can continually change along their length.

Blend-Curve

The Blend-Curve is the only sketch-element you can add with which you can control its Curvature and Curvature-Rate.