Extend Tool problem

[s45560552]

Hello, i have a problem when using alias. when im extending the edge of a surface the edge goes all over the place i feel like it has something to do with symmetry, but even when i turn off symmetry it still does the same thing. The only extend option that works is the Linear option ( along edge and extrapolate do similar things). the top part of the edge goes crazy, the bottom part does the correct thing its wierd.  Hopefully someone can figure this out. Ive shown two examples below.

A few things ive tried:

. Swapping the Us and Vs 

. Turning off symetry

. Trying the same surfaces on a diff layer

. A surface in the middle of my project ( this works properly which makes me think my symmetry plane is messed up or something)

[Michael-GG]

@s45560552 does your surface maybe have CVs lying on top of each other? Could you share the surface(s) you are having issues with here in a .wire file?

Thanks,

GG

[s45560552]

wont let me attach a .wire file unsupported. as far as i can see all the cvs are normal. Ive attached the file to a megalink below if you have time.

https://mega.nz/file/oS9g2ZQD#d4cKPO-Er0CPo5XNvxKNUlJDMqUS9U7iSzMia1kWhHs 

[Michael-GG · Accepted solution]

@s45560552 thanks for sharing the file! Unfortunately, I think the Extend result is correct. If you put a curvature plot on the top edge of your surface, and look onto it from the top, you can see that the curvature accelerates massively to the right. When choosing "Extrapolate", this direction change is continued, leading to the surface extend coming back on the top:

You need to have smoother surfaces to allow the Extend with Extrapolate to work well.
Hope this helps?
GG

[s45560552]

i see! im still a noob lol. thanks a lot for the help appreciate it!

[s45560552]

no this isnt the solution. ive made so many surfaces now and tweaked the curvature but the extend tool has a mind of its own. no idea 

[s45560552 · Accepted solution]

i guess you were right? If anyone has this problem again, i realised it was when i was using trimmed surfaces or when the CVs were really messed up. If you use Trim convert on the surface or the adjacent surface, extend tool works properly 🙂 

[amandaallsion.lila]

You can also try modifying the parameterization by just asking to reduce the spans or surface degree over in the control panel. For cv's that close to the end, it should wipe that out and just make a cleaner surface close to the original.