Add Blend-Curve
See also: Blend-Curve dialog
BUG - in MD17:
When you add a Blend-Curve, the start-Point and end-Point snap to the origin (0,0) of the Part-Editor. You must the drag the points away from the origin.
To add the Blend-Curve, drag so that the start- and end-Point do NOT merge with those of other sketch-elements. Add the Blend-Curve with free a start- and end-point. Then, after you drag the points away from the origin, use the Merge-Points command to merge the start-Point and end-Point with those of other sketch-elements.
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The Blend-Curve is now in the graphics-area. |
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To Add Blend-Curve with a free start-Point and/or end-Point.
To Add Blend-Curve with a merged start-Point and/or end-Point.
* Point, start-Point, end-Point, center-Point, Motion-Point. |
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Example
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How: |
Selection-Window Assembly-Tree |
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•Drag from the start-Point |
Blend-Curven Pointn at each end of the CAD-Line The Blend-Curve is a child to the Part. |
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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. |
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•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. |
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 Continuous Curvature AND Curvature Rate |
A Blend-Curve is a sketch-element. At its start-Point and end-Point, there are parameters to control its: •Angle •Curvature •Curvature-Rate There is also a parameter which we call its: •Velocity Scaling |
 ARCS: Tangent Arcs are NOT Smooth |
A Blend-Curve is a useful sketch-element that you can use to give a “smooth” sketch-path. See also, Smoothness definitions, below. If a sketch-path has one or more Blend-Curves, and a Motion-Point moves along the sketch-path, you join a Part (with Mass) to the Motion-Point with a Pin-Joint, it is important that: •The motion of the Motion-Point along the 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 above is NOT smooth. It has 4 Arcs that are Tangent with each other. However, the arcs have different Radii and therefore different curvatures. Therefore, the sketch-path has discontinuous Curvature at all points at which the Arcs join each other. |
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Smoothness of Sketch-elements. You are frequently concerned with the smoothness of a sketch-path. The smoothness at the transition between sketch-elements is important when a Motion-Point moves along the sketch-elements. |
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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 |