Rhino WIP Feature: FilletEdge and BlendEdge corners

[menno (Menno Deij - van Rijswijk)]

In the Rhino WIP, you will find a number of improvements related to corner surfaces created with the FilletEdge and BlendEdge commands. They can create Setback Corners. These corners usually offer better continuity and improved aesthetics.

• Setback surfaces are constructed from multi-blends.
• Multi-blend quality has improved.
• Setback now also works with concave corners.
• Multi-blends are now applied in cases where Rhino would previously create gaps.

Setback Corners

Setback corners create a softer transition where the different edges meet. In the Rhino WIP, setback corners are now also possible in FilletEdge
Setback corners are implemented with multi-blends, a number of surfaces that meet at a common central point and close a hole with multiple edges:

left: setback with 6 edges and 6 surfaces in the multi-blend; right: non-setback corner

Improved setback quality

From your feedback and from internal testing, it turned out that the existing implementation of setback corners - which is used for BlendEdge in v8 - was giving problems in a number of cases. Two examples of these problems are shown below, for acute corners and for concave edges.

Acute setback corners

On a model with sharp corners, the setbacks are wobbly, here indicated by Zebra analysis:

Rhino 8 setback

One of the reasons for the wobbliness is the surfaces that make up the corners stray outside the original shape of the model:

This wobbliness has been addressed and the Zebra light lines look much better in Rhino WIP:

Rhino 9 setback

No more bloated corners

Concave Setback Corners

In Rhino 8, concave corners - indicated below with arrows - were not supported. In Rhino WIP, this support has been added.

What’s more, continuity - as analyzed with GlobalEdgeContinuity below - is improved in many cases:

4-edge and 6-edge corners

With the re-written multi-blends, application of multi-blends is possible in more cases. Two are highlighted below, for setback and non-setback 4- and 6-edge corners.

Non-setback 4-edge corner

Setback 4-edge corner

Non-setback 6-edge corner

Download the example file… (2.1 MB)

We expect that this kind of corner with multi-blends will find its way to more cases in upcoming WIP versions.

Stay tuned for more as we continue to develop Rhino!
Download the Rhino WIP…

[skysurfer]

@menno

2. concave setback corners
In Rhino 8, concave corners - indicated below with arrows - were not supported. In Rhino 9 WIP, this support has been added.

Hi Menno, this is an amazing news and I very appreciate your effort on adressing Fillet issues.

I know it’s an hard work but on my opinion the V8 result on Setback fillets for concave corner was better. Ideally I wish to be able to manage the standard transition/setback per vertex and not just single option for session.

It would be also amazing to have the same “per edge” selction for the Railtype being able to combine different rail type togheter on different edges insede the same session.

Could it be the Xmas gift ?

[menno (Menno Deij - van Rijswijk)]

It would be nice to do both those things, but it would make the UI even more cluttered and confusing than it already is. And it will certainly not be an Xmas gift, at least not for Xmas 2025

[skysurfer]

I perfectly understand your postion.

IF worth to discuss it we can still dream how a possible UI can work.
In my opinion all this setting should not be presented at the first level but they should be a second level (option) for the command.
Also, the command should keep assigning the same solution everywere like now but, like the different radius, you should be able to change the single portion and assign the custom option.

How to visualize this is smtg we can discuss later, if make sense.

My big concern is not to forget this request.

Thanks

[davidcockey]

@menno Failure with setback corners due to fillet radius too large. Non-setback corners work correctly. Work In Progress (9.0.25350.305, 2025-12-16)

SetbackFailure.3dm (2.2 MB)

[menno (Menno Deij - van Rijswijk)]

Yes, this is a known problem RH-84177 (sorry, the ticket is closed because of confidential information). Reducing the radius is for now the only option; I hope to address this next year.

[davidcockey]

@menno

Yes, this is a known problem RH-84177 (sorry, the ticket is closed because of confidential information). Reducing the radius is for now the only option; I hope to address this next year.

@menno Is this issue likely to be resolved prior to the release of V9?

[Rhino_Bulgaria (Bobi)]

If you check how things are done in Alias, Catia and NX, they all have very detailed options for their main tools, but usually the pop-up window menus are minimalistic at first. They could be expanded by the user if needed. Rhino already have a similar approach with a few of the new tools in V9. Rhino should remember the expanded state of the menus for the current session.

Left: Fully expanded menu. Right: Default state of the menu (showing just the primary options).

[brvdln (Brv)]

Why is this happening?
inflate-patch.3dm (3.9 MB)

[menno (Menno Deij - van Rijswijk)]

I see that and we already have a related YouTrack item RH-94370.

[brian (Brian Gillespie)]

RH-94370 is fixed in Rhino WIP