I added 2 straight lines to a helix, joined the curves, and wanted to fillet the 2 sharp corners. one corner can be filleted, the other one fails.
any clues why? the geometry seems OK to me.

if you Scale x 1000 that will be working!
(radius 10 mm)

Hi Wimverbe,

10/1000 = 0.01. Without changing the scale, you can make a filletr of 0.01, you can go up to 0.05 maximum.

What value do you want?

Hi wimverbe,

Look at the script DelCorners because using fillet on curves is maid to plannar curves, not to 3D.

https://moi3d.com/wiki/MaxScriptArchive

If the smooth is to heavy with it, add a point on your straight lines to choose how far is the curvature.

Have fun

You can also use Rebuild or ReconstrutCurve but the tuning is different.
It depends on your result needed.

Test them and choose the best way for your needs

Pilou, I tried that, but then I need a corner radius of 2000 mm, and that still fails. 10 mm works, but not what I want.

the 2 points are almost identical in situation, I don't see why one works well and the other doesn't.

I did some more testing, it has to do with the angle between the spiral end and the straight line.

helix axis is 10mm, desired fillet is 2mm.

Hi Wim, curve filleting needs each curve to be on the same plane.

In your case here the helix is not a planar curve, that is why it fails.

A different technique that you could try is to trim out some empty space between the 2 curves and use Construct > Blend to put in a smooth blend curve.

- Michael

Now I am totally confused!

if what you say is true, then my intuition tells me it should be the other way around, then the line that goes straight down, perpendicular to the last segment of the spiral, lies in the same plane, and should work, the angled one is definitely not in the same plane and yet that one works...

anyway, I found a way to make it work for me, just thought I should mention this. no big deal ;-)

Hi Wim,

re:
> the line that goes straight down, perpendicular to the last segment of the
> spiral, lies in the same plane, and should work, the angled one is definitely
> not in the same plane and yet that one works...

Neither line is in the same plane as the helix, because the helix itself isn't on
a single plane. It's a non-planar curve.

However it is close to being coplanar if you stay in the general area near
the end of the helix.

That is enough for the fillet solver to get some solutions if it is lucky. But the
arc generated in these cases is not exactly tangent to the neighboring curves.

- Michael