I filleted this in the Parasolids Kernel and it seemd to still bunch up in that area. I had several options, which would section the fillet up in different ways, but they all seemed to produce some curvature irregularities in this area. Some of the available tools here also were to dynamically re-tolerance the solid to have the fillet succeed. For instance, here it re-toleranced to .04 to allow a 4 inch fillet.



Note the additional sectioning done in the surface construction, though the analysis still shows the issue:



This one is "maintain Parabolic curves" in the fillet options

Hi Burr, well that's interesting that it makes that kind of result, it seems that it knows that the fillet would become self intersecting there and attempts to do something else.

The problem is the bunching at the top here:




Fillet surfaces are basically like a loft through a bunch of cross-sections, and surface lofting just does not behave well when one side of the loft is all compressed together like that, it will tend to generate those kinds of little ripples and lumps.


The one in MoI solves this by putting in a blend curve at the top so that there isn't a compressed side like that:




- Michael

Thats really cool that MoI does something like this well that it seems every other fillet'r has issues with. The result I showed is from Delcams Powershape using the Parasolids kernel, Which is more of a mid range modeler like solid edge or solidworks, though it still gives a bunch of fillet options. I could get it to section up in many different ways, not just that "pole position" result, but they all did the bunching. None did what MoI's does.

Maybe Parasolids needs to see this example to incorporate...LOL

I think another possible reason is the lack of topology, the model does not have very many edges and solid modelers really crave ordered topology.
Like how the sides are just two big surfaces is complicating.

Hi Kevin, I'm not sure if a change in topology would make much difference in this case, since it's one smooth shape there is not really any obvious topology changes to make unless you would change the shape to be made of line segments and arcs or something like that rather than 1 smooth curve. But then that would be a different model...

- Michael

Hi Burr,

> Maybe Parasolids needs to see this example to incorporate...LOL

I wouldn't be surprised if they would incorporate it at some point actually... It seems that they are recognizing that the regular fillet would self-intersect and at least trying to do something about it.

It actually tends to be better to get a result back even with those little ripples in it rather than nothing at all because then you may be able to do some surgery on it to trim out the bad part and fill it in with something else.


One of the more interesting parts of this is not really so much that MoI's filleter can generate this case better (which is going to be a rather rare occurrence), but rather that you can actually see the little ripples with MoI's regular display rather than having to go to a special analysis mode or possibly not even being able to see it at all in some programs even in analysis modes.

- Michael

Ah yes. The other program presents to you a fillet that "appears" to be very nice. (Unless analyzed)

I find MoI to be very good at inspecting geometry! (hence my V3 wishlist request for sectioning) It really is powerful in this sense.

Here`s some samples from CoCreate, ProE and SolidEdge ST1






















Will checking also the IronCAD LATER.

Thanks,

d3

Hi Michael,

After having a bit of time doing this it seems NX struggles a bit also, it does manage R=3 with Edge blend and Face Blend before the surface gets funky when you go over R=3, the Soft Blend option is at R=4, had no time to analyse the results, so I've attached a .3dm with all three, they are all named according to what method was used to fillet.

Cheers

Hi Danny, the edge blend and face blend ones (the 2 on the left) are interesting - it kind of looks like it switched to a sort of rail-revolve type generation in that area. Those are nice on the interior portion of the revolve but has a kind of bump or lack of continuity where the corner patch touches the fillet. You can see it clearly if you turn on metallic lighting in MoI and hide the edges:






The soft blend one seems pretty good though, maybe just tiny subtle hint of a lump in one spot. The control points on it are clustered in some areas but it doesn't seem to suffered much for it at least in this particular case:



- Michael

Here`s IronCad 1,7 mm round. R1,75mm didn`t work for basic round.


Thanks,

d3