topic Re: Offset 2D Sketched Spline in Inventor Forum

Offset 2D Sketched Spline

machiningllc — Sun, 12 Jan 2020 00:50:58 GMT

I was wondering if anyone has had an issue offsetting a 2D sketched spine. For some reason I can online offset in the positive direction not the negative. To be clear it does let me offset in the negative direction but only like .007". Attached is the pack-n-go of the part.

Re: Offset 2D Sketched Spline

jhackney1972 — Sun, 12 Jan 2020 01:42:09 GMT

If you are talking about the part Broken.ipt, the sketch cannot be offset in a Negative direction, inside the part, because it overlaps itself and becomes a segmented circle. There is no issue with the sketch offset command. If you want the sketch to be the same shape but smaller on the inside, use the sketch Scale command.

Next time you post a single Inventor part, do not use Pack and Go. You use Pack and Go for gathering Assembly files along with all their associated parts. When you do use Pack and Go, make sure you check the two indicated boxes. No one wants to see your templates and Design Data.

Re: Offset 2D Sketched Spline

machiningllc — Sun, 12 Jan 2020 04:50:09 GMT

Well you nailed it. Thanks for your reply but it offsets fine in Fusion. Not sure why it just does.

Re: Offset 2D Sketched Spline

JDMather — Sun, 12 Jan 2020 14:26:33 GMT

Can you File>Export and then Attach your Fusion *.f3d file here?

Re: Offset 2D Sketched Spline

johnsonshiue — Mon, 13 Jan 2020 23:01:12 GMT

Hi! Without seeing the file, I can almost tell it is probably due to curvature or tangency of the spline. In some section, the inward offset might cause change in topology (one curve has to become two curves or there has to be a sharp corner). Inventor Spline Offset does not know how to handle it.

The workaround is to Extrude the source spline as a surface. Next, use Thicken/Offset command to offset the surface body inward. Then, project the edge to a sketch.

Many thanks!