Why is tangency not working on this fill?

znerol_1

Hi Everyone,

total noob here, I tried to understand the documentation but struggeling a bit.

The goal is to create a surface that would be continuous without ridges when mirroring the part on X,Y,Z axes.

However the fill tool shows an error when i try to select tangency, something about continuity requirements too high, i do not understand.

On each corner all edges meet at 90 degree angle.

Now the surface created has these ridges i would like to avoid.

How to proceed?

Cheers,
Loz



https://cad.onshape.com/documents/b043e2322c85fa8ddb6c4038/w/a13dcb4e77998f0d4ef35f99/e/99d8f5411e8417b29a936c46?renderMode=0&uiState=661beb0f9849bb38e72ca06b

S1mon

You can also use Loft in this case. It's not really the recommended way to do things, because the center becomes mathematically degenerate. However, if all the constraints are carefully constructed, it can work.

A better solution would be break the surface up into more pieces. Here I swept part of sketch 4 along sketch 1, trimmed it and used a boundary surface with curvature along the trimmed edge. Note that I needed to finish constraining sketch 4 so that the boundary surface didn't give errors in tangency. The end result is very clean.

https://cad.onshape.com/documents/23cf07b040f2a323da438f3c/w/80d12e10571940b43e63596a/e/c69178cd58f77336c81363fb

znerol_1

I managed to make some progress by sketching beziers more carefully, however I'm back to the same problem that I can not have dtangency on all faces, where am I going wrong? 

The goal is to be able to mirror the fill so that one seemless object is created, without ridges

BR,
Loz

steven_van_luchene848

fill-experiment - Copy | Wing (onshape.com)

I first extruded the curves to have a surface to reference in the fill surface tangency option. 
don't know if this is the right way but seems pretty ok. 

S1mon

You can also use Loft in this case. It's not really the recommended way to do things, because the center becomes mathematically degenerate. However, if all the constraints are carefully constructed, it can work.

A better solution would be break the surface up into more pieces. Here I swept part of sketch 4 along sketch 1, trimmed it and used a boundary surface with curvature along the trimmed edge. Note that I needed to finish constraining sketch 4 so that the boundary surface didn't give errors in tangency. The end result is very clean.

https://cad.onshape.com/documents/23cf07b040f2a323da438f3c/w/80d12e10571940b43e63596a/e/c69178cd58f77336c81363fb

glen_dewsbury

This can be accomplished with a loft as well. You may want to take a close look at your sketches. I found some odd things that produced a weird bulge when working with the fill tool. See branch B1.
When I did this as a fill a number of additional surfaces had the be added for surface tangency.
https://cad.onshape.com/documents/3a175201b2a90288a66bf364/w/832bdec234823eadedb081fa/e/c5dee3ddde2de4b3e71f9b26

znerol_1

@S1mon thank you very much! That was a great idea to slice through it half way up, that was the pointer I needed!!