Very helpful, thank you!

I tend to create my extrusion shapes by boolean'ing together a series of 2D shapes first so I guess I need to pay more careful attention to how those shapes connect up with each other. Definitely a learning curve here and I appreciate the help! NURBs modeling isn't something I do every day...

Nice, so through building with a different mindset I was able to get it to fillet. Looks awesome in 3DSMax too.

OK, so I just need to come to grips with NURBs modeling then. Gotta make room for yet another workflow in my tiny brain. :)

Thanks all!

Nice work.

Yes the vertical one can permit to fill all the Curves in the same time! Of course with a very little fillet!
But of course that makes a fillet also on the vertical one! :)
But as said previous your curves were not well reccorded! :)

Hi Warren, it sounds like you've got this figured out now, but just in case:

> I guess the problem lies in how I created the outer scallop shape in the first place then?
> That vertical line seems to be the fun killer. Is there a way to remove it or does it all come
> down to how I create things in the first place?

The vertical line is a problem because the surfaces on either side of it are not smooth to one another, they come to about a 15 degree angle and these kinds of shallow angles where things are sort of close to being smooth but not quite actually smooth tends to make things difficult for filleting.

It isn't necessary to totally remove those vertical lines, but what you want is for the surfaces on either side of it to be tangent to one another rather than only slightly creased to one another.


> Basically, get the first steps right or it's never going to work?

Yeah it helps avoid a lot of problems if your original curves that were extruded were tangent to one another.

For filleting it's usually best if things meet at a sharp angle to one another or are smooth where they meet. Things that are just kind of close to being smooth but not actually smooth (like say 5 or 10 or even 15 degrees off like in your case here) make things a lot more difficult for the filleting mechanism. That's because anytime you have pieces meeting sharply to one another at all the fillet segments that follow them will not line up directly to one another and will need to be trimmed or have corner juncture pieces put in place, and when things at at shallow angle the various calculations that go into that become more difficult.

- Michael

Hi Warren,

> Is the general idea in MoI "large sweeping actions" rather than "small, cumulative actions"?

It kind of depends on the particular circumstance. But it can make things easier for filleting if you have larger pieces because a single large non-segmented curve or large surface piece will be all smooth inside of it. So that can tend to avoid ending up with things meeting up at some slight shallow angle.

Slight shallow angles between pieces will tend to cause problems with filleting.

- Michael

" ... I tend to create my extrusion shapes by boolean'ing together a series of 2D shapes first"

I've had good luck building smooth 2D profile closed curves by drawing the critical segments first, then use Blends to bridge the gaps. That is, use Blend to create the radius transitions to complete the closed curve.

This has given me no problems when it comes time to extrude and fillet the resulting solid.

Perhaps Michael can chime in and explain if a Blend on two line segments will always be tangent where they join.

I may be drawing curves in a more complex way than necessary, but I find Blend works well for 2D drawings.

Click image to enlarge.

Ed

A great way of creating tangent relationships.

HI ed,

> Perhaps Michael can chime in and explain if a Blend on two line segments
> will always be tangent where they join.

Yup, a blend between 2 line segments will be tangent to each line segment.

- Michael

Does this the same in the 3D Space when curves are and come from anywhere orientation ?
I suppose yes but ...

Hi Pilou,

> Does this the same in the 3D Space when curves are and come from anywhere orientation ?

Yes, the blend will still be tangent to each curve even if the curves are not in the same plane.

The blend part itself will not be flat in cases like that, it will bank around to meet up with the curves.

- Michael

Thx now I am sure! :)

Nice! That's really helpful, thanks for the Blend tip.