How to constrain a trimmed offset off a spline?

[kevinwilcox46]

Hi all, does anyone know how to constrain the trimmed offset off a spline in the attached? The methodology is as follows;

1. create a fit point spline

2. offset it and join one open end with a straight line

3. draw another straight line connecting one end of the offset spline to the opposite end of the original spline, bisecting the offset. At this stage the profile remains fully constrained as per the left hand drawing.

4. trim the unwanted sections of line to just retain the profile for extrusion. Right hand drawing - at which point it doesn't seem possible to constrain the offset line.

From a production perspective it doesn't really matter that I can't find a way to constrain this as I can't see any way in which it can move, but I'm trying to religiously have fully constrained sketches and it bugs me that I can't find a way to do so on this one.

Thanks

Kevin

[HughesTooling]

Why do you need to trim the offset spline? You can just extrude the closed profile and the extra part of the spline doesn't matter. I you need the sketch for something else then create a second sketch and project the surface edges after extruding.

Mark

[etfrench · Accepted solution]

Fix/UnFix will constrain a spline.

[kevinwilcox46]

Hi Mark, I don't really need to trim, it's just another thing I'm systematically doing as it reduces the clutter on particularly busy sketches. If there's no way of maintaining the constraint, I'll probably not trim.

[kevinwilcox46]

Perfect, thank you.

[g-andresen]

Hi,

1. offsets become unconstrained by trimming.
2. if you want to define splines, you are better off with control point splines. Unlike fit point splines, these require fewer definitions.

günther