A Tip on dealing with edges that consist of tolerant curves 3

[jerry1423]

Edges that consist of tolerant curves are approximations of edges and, in my situations, tend to occur on models imported from another source. They seem to occur most frequently when the solid is made from sewn sheets bodies (aka surfaces).
They can cause problems if they need to be referenced (dimensioned to, constrained to . . . )
In the passed I have needed to redo the part of the model that has the edge, such as removing the hole faces and putting a new hole in - but when the edge is on a more complex area of the body, such as the exterior of a part, replacing that part of the model may not be as easy. So . . .
[highlight]Below is a method to convert an edge that consists of a tolerant curve to a precise edge with definition:[/highlight]
[ol]
[li]Add a blend to the edge that consists of a tolerant curve. If the sheet bodies are not touching within tolerance then a face blend may need to be used.[/li]
[li]Remove the blend using "Delete Face" in Syncronous Modeling. Insert -> Syncronous Modeling -> Delete Face[/li]
[li](Optional) Remove the parameters from the solid body. Edit -> Feature -> Remove Parameters[/li]
[/ol]
[li]The above method should work for all versions of NX.[/li]
[li]In NX6, and newer, you can work in "History Free" mode and eliminate the third step.[/li]
[li]Prior to NX6 the "Delete Face" function is found under "Edit Face" not in "Syncronous Modeling"[/li]
[li]Instead of blending (in step 1), a chamfer may be used, but typically blends work out better, as they are more robust.[/li]

Attached is a movie showing this method on a very simple round part. I did not "remove parameters" in the movie because I wanted to keep it as short as possible.

 

[uwam2ie]

thankyou,
but I don't understand your avi

 

[jerry1423]

The movie shows that the edges were converted from edges with tolerant curves, to circles and arcs. That info was is showing in the window on the lower left side.
I had a limit to how long the movie could be so I left some steps out that would have made things more clear.
The reason it is important that they were converted to circles and arcs is now they can be dimensioned to, or constrained to.

 

[animuL67]

jerry, your method worked great to regain a nice edge. Previously I would have edited the curve length of the bad edges by shortening it a little, say .01. Then I would trim and extend the edge .01 or so and bridge the curves with the bridge constrained to the faces. Then trim the sheet to the curves. This would get me a contiguous edge but it would be segmented. Your method gets me an unsegmented edge so props to you! Its just too bad still that this happens in the first place.

 

[jerry1423]

I am glad it worked for you.
It was a bit of a fluke that I was able to come up with that method, after many years of dealing with tolerant edges on models from other sources.