Blend-Curve

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Blend-Curve

Add Blend-Curve

See also: Blend-Curve dialog

MD-Toolbar-SE-AddBlendCurve

Add Gearing FB

1.Click Geometry toolbar > Add Blend-Curve

OR

1.Click Geometry menu > Blend-Curve

2.Drag in the graphics-area from the start-Point to its end-Point.

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

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

To Add Blend-Curve with a free start-Point and/or end-Point.

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

See also: How to Delete a Constraint

To Add Blend-Curve with a merged start-Point and/or end-Point.

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

See: Hover+Drag Video

Note:

The Blend-Curve automatically adjusts its Angle, Curvature, and Curvature-Rate to equal those of the sketch-element with which you merge the Blend-Curve.

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

Example

MD-GA-Geometry-AddBlend-Curve

How:

Selection-Window

Assembly-Tree

•Drag from the start-PointRed-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 in the upper image has been added by dragging from lower-left to upper-right.

•The Blend-Curve in the image to the left has been added by dragging from upper-left to lower-right.

MD-GA-Geometry-AddBlend-Curve-C

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

•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 is a useful sketch-element for smooth sketch-paths.

You can control these parameters at its start-Point and end-Point:

•Angle

•Curvature

•Curvature-Rate

•Velocity Scaling

 
btn_delkeywordWhy use a Blend-Curve?
ARCS: Tangent Arcs are NOT Smooth

ARCS: Tangent Arcs are NOT Smooth

 

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

If the Blend-Curve is to guide a Motion-Point which also guides 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 does not have discontinuities in angle, curvature, and rate-of-change of curvature at places when the velocity of the Motion-Point is not zero.

The sketch-path in the image is NOT smooth - It has 4 Arcs that are Tangent with each other. The arcs have different Radii and therefore different curvature. Therefore, the sketch-path has discontinuous Curvature at all points at which the Arcs join each other.
btn_delkeywordSmoothness definitions

Smoothness of Sketch-elements.

You are frequently concerned with the smoothness of a sketch-path.

The smoothness at the transition between sketch-element is important when a Motion-Point moves along the sketch-elements.

 

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