Sketch could not be solved after Offset Tool

Tygan

Hi,

I am trying to offset a projected path, but after using the offset tool the sketch is broken. Looks like it overdefined the new path.



Can someone tell me what I am doing wrong?

NeilCooke

For whatever reason, it really doesn't like offsetting the spline - can the spline be approximated with two tangent arcs in your first sketch?

steve_shubin

@Tygan

Here is one way of doing it. I don’t know exactly what you want to do — if you want to make a curb or recess around the edge. But at least this is a starting point

https://cad.onshape.com/documents/3d3aafee9b8119dafff4ddfc/w/dd92e99728e2299f5b7b6c5c/e/4ae724eedef114add551019c

john_mcclary

Instead of individually selecting each edge, click-drag one of the edges, see if that helps

Tygan

I am not sure what you mean with "click-drag one of the edges"

Selecting all Edges like this does not work:



Offsetting each Edge individually does not break the Sketch but the Edges are not connected:

NeilCooke

Watch this video: https://learn.onshape.com/learn/course/fundamentals-sketching/sketch-tools/additional-sketch-tools

NeilCooke

I imagine it is something to do with offsetting the spline. If you paste the doc URL here we can take a look.

Tygan

Here is the Link: https://cad.onshape.com/documents/0c0d80dd73ef05ffcf9dd817/w/0d574aee88120cb1a1c788d2/e/b62aa3589c67efaf7458e06e
Thanks for the help so far

NeilCooke

For whatever reason, it really doesn't like offsetting the spline - can the spline be approximated with two tangent arcs in your first sketch?

steve_shubin

@Tygan

Here is one way of doing it. I don’t know exactly what you want to do — if you want to make a curb or recess around the edge. But at least this is a starting point

https://cad.onshape.com/documents/3d3aafee9b8119dafff4ddfc/w/dd92e99728e2299f5b7b6c5c/e/4ae724eedef114add551019c

steve_shubin

@Tygan

Tygan

NeilCooke said:

For whatever reason, it really doesn't like offsetting the spline - can the spline be approximated with two tangent arcs in your first sketch?

It is working with two tangent arcs but not as smooth as the spline. I have to experiment a bit and find the sweet spot where the arcs have to touch.

Thanks for the help! 

Tygan

steve_shubin said:

@Tygan

Here is one way of doing it. I don’t know exactly what you want to do — if you want to make a curb or recess around the edge. But at least this is a starting point

https://cad.onshape.com/documents/3d3aafee9b8119dafff4ddfc/w/dd92e99728e2299f5b7b6c5c/e/4ae724eedef114add551019c

This is what I want to do. Looks like the offset tool is working on the original sketch and it does not like the projected lines.
Thank you

romeograham

Another option is to extrude a body or surface, and use Offset on the outside faces - sometimes Boolean operations are more robust than offset sketches.

anton_schwalbe

You need to remove all constraints on the lines first.

glen_dewsbury

@Tygan
I was curious since I've un into this before. Initially I tried offsetting the splines separate from the lines. This worked for the first iteration but failed when I tried to repeat for another size down. Leaves a sketch that's not closed and splines that can't be trimmed to close sketch.
Thinking of Romeo's comment.
Next I tried using a zero offset surface. Then move boundary to give an equivalent to offset sketch entities. Now extrude that surface. Seams to be very robust and could be repeated many times.
https://cad.onshape.com/documents/7fb24d72c892d33717e21947/w/32177e12b69dc58632581df4/e/1d7abdc3178700278bb0e63e