Copying spline from one sketch to another with linked behavior

[Anonymous]

Create a sketch

Draw a spline

Draw a line

Mirror the spline across the line.

At this point, you have two "linked" splines. If you change the shape of one, the other changes with it.

So far, so good.

What I want to do is copy this pair of splines to a different sketch, but keep the linking - ie, change one spline, all four change in the same way.

I tried cut/paste, but the pasted splines are not linked back to the originals.

I have no idea what to try next.

Thanks

[jeff_strater · Accepted solution]

unfortunately, as far as I know, there is no way to do this.  The only associativity in sketch is mirror or pattern, there is no linking to geometry in another sketch.  The only thing I can think of is if your second sketch is parallel to your first sketch, then you can use Project to project the first pair of splines into the second sketch.

Jeff

[Anonymous]

This suggests a solution, at least in my case. The two sketch planes meet in a line that is the desired mirror line. A solution that works is to

1. Create one of the sketch planes and draw/mirror the splines.

2. Create the second sketch plane.

3. Create an intermediate helper plane that bisects the angle between the two sketch planes.

4. Create a new helper sketch in the helper plane and project the splines on the helper sketch.

5. Create a sketch in the second sketch plane and project from the helper sketch to the second working sketch.

All the splines are now associated. Not a very pretty solution (or a very general one), but it works.

Thanks for the idea that prompted the solution.

[Anonymous]

Hi there

Have you got an example of this in action? Battling to get it to work!

Cheers

[Anonymous]

Sketch 1 contains the original spline

Sketch 2 - create a plane at 45° to the plane of sketch 1, then Sketch->Project/Include->Project, select the spline

Sketch 3 - create plane 90° from sketch 1. Sketch->Project/Incude->Project, select the projected spline

All three splines are controlled by the spline in Sketch 1.

[Anonymous]

Here's a screencast

[Anonymous]

Thanks for getting back to me thats what I thought you meant and I have
followed exactly but does not work. I have tried just this again following
your process and the resultant sketch is far from the original, can you
show me an example of how you can do this? Many thanks

[laughingcreek]

I can think of 2 ways to to maintain a conection between a sketched spline, and copies/mirrors of it.

1-put the sketch in a component, then make copies of that component and arrange them however you want. (can be a little unwieldy depending on the situation.

2-create a surface (or some other geometry) and copy/mirror the geometry.

Attached is a file for a table I just posted to a different thread where i use the 2nd method to draw the outline of the leg just once, and then pattern a surface made from it.

[Anonymous]

I looked at your file and this is an interesting solution. In my case, I was trying to loft between two copies of the same spline, so you approach of creating a surface introduces some stray edges of the patch that are unnecessary, but if you just think of them as construction lines, it's no big deal. At first I had problems creating the patch because I didn't notice that while the leg sketch was visible, the sketch group was toggled invisible. Once I got that fixed, I was able to reproduce how you produced the patch.

The beauty of this approach is once you've created the patch/face, you can rotate and move it while maintaining the linkage to the original. Very powerful. Thanks

Advice to anyone trying to follow how this model was made - many of the bodies and sketches are set to invisible, so if you move the time-line slider, nothing seems to change, just the model disappears. Make everything visible so you can see what's happening.