Hi Michael!

How could I fillet this curve with this request (explained by the picture) ? How about this idea?
It is similar than the Sweep command /point end option.

the picture

Hi andras, I think you're asking for what is called a "variable radius" fillet?

That's a fillet mechanism where you can specify different radius values at different spots along the edge and the fillet changes between those values as it travels along the edge.

I do want to include that kind of fillet function in MoI in the future.

- Michael

Mmmm, variable fillets. Tasty.

V3 maybe?

Hi Tony,

re: variable radius fillets

> V3 maybe?

Possibly - it's a bit too early to know if that in particular will be in v3 or not.

There are a variety of other things that seem to be requested more frequently.

- Michael

Variable radius fillet request!

Hi Burr, do you have an example of a situation where it would have been useful for you?

- Michael

I'd really appreciate that feature Michael. A variable radius fillet would be most useful.

Me too :)

just the other day I was trying to make some cool looking wings for a space flyer, and variable fillet (along the wing's length) would have been perfect!

>>>>Hi Burr, do you have an example of a situation where it would have been useful for you?>>>>

The little reel drag I made and had printed comes to mind. I think I sent you the model?

There were some areas that I couldnt put a filet because it pinched down to a point. If I could have made the filet start at 0 and move larger along the path, I could have created some transitions I wanted. Mostly on the little ball end. Some others I come across are just the ability to eliminate a filet size limitation due to 1 small portion being narrow, when the majority of the edge needs a larger filet.

As well as variable radius for fillet (and a similar variable Distance for chamfer), I was wondering if there could be an addition of a "Use 2 distances" for the Fillet tool, exactly the same as there currently is with the Chamfer tool?

I think ViaCAD, Free SketchUp7---Blender----all have it now?

Brian

Hi Burr,

> There were some areas that I couldnt put a filet because it
> pinched down to a point.

That would probably be better off as a bug fix to the regular filleter, to handle that kind of "disappearing fillet" problem.

There are some of those kinds of cases where they are handled currently but not everywhere.

A variable radius fillet is different than a "dispappearing fillet" case, it produces a different kind of a shape with the fillet rails kind of bending around somewhat.

- Michael

Hi Brian,

> I think ViaCAD, Free SketchUp7---Blender----all have it now?

I think ViaCAD yes - but SketchUp and Blender? No - those are not even NURBS based applications so no NURBS surface variable radius fillets will be found in there...

I think that Blender is in the very early stages of adding in some basic NURBS functions. But filleting is an extraordinarily difficult area to implement, it's something that is going to likely take a very long time and a lot of effort before it would be implemented there.

ViaCAD on the other hand has a really good filleting mechanism in it (calculation-wise, the UI is somewhat awkward), that's one of the reasons why it can be a nice companion to have to use along side MoI.

- Michael

Hi NightCabbage,

> I was wondering if there could be an addition of a
> "Use 2 distances" for the Fillet tool, exactly the same as
> there currently is with the Chamfer tool?

Well, that's a rather unusual combination for CAD programs.

It's not really clear exactly what the result should be - having 2 distances with a rounded connection would maybe imply some kind of ellipse shape?

But keep in mind that the surfaces being filleted can change in angle to one another and are not necessarily only at a 90 degree angle to each other like a simple ellipse case would be set up for.

I guess it could be theoretically possible to do a "2 distance" rail generation but then use a blended surface generator between them... But that would be pretty unusual, and probably not compatible with corner patch generation that currently exists in the geometry library that MoI uses.

You can get a similar result currently if you do the chamfer, then delete the chamfer and put in a Blend between the exposed edges... Try using that technique.

Filleting is already a shaky enough thing as it is, so it's not really that feasible to have too exotic of combinations and expect for them to do much...

- Michael

No problems, understandable :)

Hi Michael

There was something about a plugin I thought for SketchUp quite recently?
Certainly other than ViaCad?

You may be interested in this about Blender Nurbs.
(A lot more info about)

http://download.blender.org/documentation/oldsite/oldsite.blender3d.org/117_Blender%20tutorial%20Fun%20with%20nurbs.html

Brian

Hi Brian,

> There was something about a plugin I thought for SketchUp quite recently?

For actual NURBS surface variable radius fillets? Pretty unlikely, but if you find the link please post it.

You're probably talking about some kind of sweeping technique for generating polygons from some profile curves, that's not the same thing as a fillet.


> Certainly other than ViaCad?

Yeah, it is not unusual (and in fact rather common) in NURBS based CAD programs to have it. But neither SketchUp nor Blender are NURBS based CAD programs.


> You may be interested in this about Blender Nurbs.
> (A lot more info about)

It is interesting! But please note that the tutorial you link to is all about control point manipulation of an untrimmed surface.

That does not particularly have anything to do with variable radius fillet generation.


Maybe you are confused because it refers to "NURBS" as well?

Just be aware that NURBS can sometimes refer to a just a simple surface by itself and not necessarily trims, booleans, fillets, and additional stuff like that.

As far as I know Blender does not support any of those kinds of Trimmed NURBS operations, like booleans for example. Getting those kinds of operations working is a very considerable jump in complexity from basic untrimmed surfaces.

- Michael

You can now in Google Sketchup free make variable fillet as you can make a "sweep" with 4 curves
Extrude Edges by Rail by TIG
http://forums.sketchucation.com/viewtopic.php?f=323&t=23662&start=0#p201286

Hi Pilou, that's nice, but that is not a variable radius fillet that you are showing there.

A variable radius fillet is similar to a regular fillet - it is a new smooth surface that is calculated between 2 existing surfaces, with ensured tangency where the new surface touches the others.

The one you show there is like a sweep - it's not a connection between 2 existing surfaces, and since the output is only polygons there is no kind of tangency in the generated surfaces either...

Here is an example of what a variable radius fillet looks like, the fillet surface is in red:



So note that it is trimming away what used to be a sharp connection between 2 surfaces just like a regular fillet, except that the fillet radius is changing between different values as it travels along the edge.

- Michael