Geometry | Blend-Curve

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Geometry | Blend-Curve

Add Blend-Curve

See also: Blend-Curve dialog-box

MD-Toolbar-SE-AddBlendCurve

Toolbar :

Part-Editor: Geometry toolbar > Add Blend-Curve

Menu :

Part-Editor: Add menu > Geometry sub-menu> > Add Blend-Curve

To Add :

1.Part-Editor: Click Geometry toolbar > Add Blend-Curve

2.Part-Editor: Drag in the graphic-area from the start-Point to the end-Point.

Drag: mouse-button-down (start-Point), move your mouse-pointer, mouse-button-up (end-Point).

The Blend-Curve is now in the graphic-area.

To Edit :

See Blend-Curve dialog-box and Drag-Handles

Note:

Add with Free-Points*

Do NOT HOVER above a Point* before you mouse-button-down or mouse-button-up.

See also: How to Delete a Constraint

Point* : start-Point, end-Point, center-Point.

Add with Merged-Points*

Do HOVER above a Point* before you mouse-button-down or mouse-button-up.

See: Hover+Drag Video

Point* : start-Point, end-Point, center-Point.

Example

How:

Selection-Window

Assembly-Tree

MD-GA-Geometry-AddBlend-Curve

•Drag from the startRed-14-1b to the end PointRed-14-2 of Blend-Curve

Blend-Curven

Pointn at each end of the CAD-Line

The Blend-Curve is a child to the Part.

MD-GA-Geometry-AddBlend-Curve-B

The default Angle, Curvature and Curvature Rate at the start-Point and end-Point of the Blend-Curve are zero.

The images to the left and above are default Blend-Curves.

•The Blend-Curve at the top has been added with a drag from bottom-left to top-right.

•The Blend-Curve at the bottom has been added with a drag from top-right to bottom-left.

MD-GA-Geometry-AddBlend-Curve-C

•Hover + Drag from the end-Point of a different sketch-element to merge the start-Point of as new Blend-Curve.

When you merge the Blend-Curve with a sketch-element, the Blend-Curve matches the Angle, Curvature and Curvature Rate with the other sketch-element.
btn_delkeywordWhat is a Blend-Curve?
Continuous Curvature AND Curvature Rate

Continuous Curvature AND Curvature Rate

A Blend-Curve can give a complex. but very useful 2D path

Blend-Curve Parameters at its start-Point and end-Point:

•Angle

•Curvature

•Curvature-Rate

•Velocity Scaling

 
btn_delkeywordWhy use a Blend-Curve?
Tangent are NOT Smooth

Tangent are NOT Smooth

Use Blend-Curve to give a smooth sketch-path. See also Smoothness.

If the Blend-Curve is to guide a Motion-Point which will also guide a Part, it is important that:

•The motion of the Motion-Point along a sketch-path does not have discontinuities in position, velocity, acceleration, and jerk.

and:

•The shape of the sketch-path itself does not have discontinuities in angle, curvature, and rate-of-change of curvature.

<<< This path is NOT smooth - Tangent arcs (with different Radii) have discontinuous Curvature.

Blend-Curve - Drag-Handles

btn_delkeywordEdit Approximately

MD-GA-BlendCurve-Handles-A

To show the Drag-Handles

1.Click the Blend-Curve one time

You can now see the four(4) Drag-Handles - two(2) at the start-Point and two(2) at the end-Point

The Drag-Handles are fixed (Green) when you show them. You cannot drag them in this state.

There are two(2) Drag-Handle types:

Red-14-1 Arrowhead Drag-Handle

Red-14-2 Circle Drag-Point

Arrowhead Drag-Handle

1.Double-click an Arrowhead Drag-Handles

The Drag-Handle should now be blue

2.Drag the blue arrowhead

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

Red-14-2 Drag the arrowhead away from the Point to increase the Velocity-Scaling factor

MD-GA-BlendCurve-Handles-B

 

MD-GA-BlendCurve-Handles-BDrag

Circle Drag-Handle (See the bottom image)

1.Double-click one of the Circle Drag-Handles

The Drag-Handle should be come blue

2.Drag the blue circle

Red-14-1b Rotate the Circle Drag-Handle around the Point in a clockwise direction

When the Circle Drag-Handle is:

•is at 90º (vertically up) the Curvature is 0 (a straight-line)

•is at 270º (vertically down) the Curvature increases to +ve large value

Red-14-1b Rotate the Circle Drag-Handle around the Point in a counter-clockwise direction.

When the Circle Drag-Handle is:

•is at 90º (vertically up) the Curvature is 0 (a straight-line)

•is at 270º (vertically down) the Curvature increases to -ve large value

MD-GA-BlendCurve-Handles-BDragB
btn_delkeywordSmoothness definitions

Smoothness of Sketch-elements.

You are often concerned with the smoothness of the sketch, especially at the transition between sketch-elements. This is important when the sketch-path is for a Motion-Point that also moves a kinematic-chain.

 

Angle

Curvature

Curvature Rate

Line joins a Line

Can 'kink', be the same angle (why two Lines?)

NA

NA

Arc joins a Line

Keep the same Angle

Keep the same Curvature (or Radius)

NA

Arc joins an Arc

Keep the same Angle

Keep the same Curvature (or Radius)

NA

Blend-Curve joins a Line

Keep the same Angle

Keep the same Curvature=0 (infinite Radius)

Keep at 0

Blend-Curve joins an Arc

Keep the same Angle

Keep the same Curvature; Radius

Keep at 0

Blend-Curve joins a Blend-Curve

Keep the same Angle

Keep the same Curvature; Radius

Keep the same Curvature Rate