Hiya good folks.
I'm not exactly a beginner but I've been hitting a problem a LOT recently with filleting (I know, *sigh*, sorry) and it's just driving me nuts because I'm positive the solution is simple. Being a complete sycophant for MOI3D .. I suspect it's just me.

trying to run a simple circular fillet:






I've studied and studied this model, pulled it apart and rebuilt it etc. a lot. It's not just this model but indicative of pretty much the only consistent problem I run into.

Hola Ricardo :)
quick fix:

delete that surface



select both edge loops and union,these will be rails sweep



draw two lines as sweep sections and do the sweep



join bigger surface with the blue one,then with the bottom surface,hit NAKED EDGES to check if all is joined and fillet works



file attached

M

Hi Rico - similar type of thing as Mauro posts above (he beat me to it!) -

The problem is the existing segmentation of faces there makes for a bit of a difficult overlap area in the fillet in this area here:



I got the above fillets set up by separating your model into individual surfaces and selecting 2 surfaces at a time and running fillet, that does a somewhat different surface/surface fillet operation which is calculated between surfaces and not by tracking along edges. So I could see from that, that there is a kind of overlap area between the fillets and the regular edge based filleter does not seem to be doing a proper job of dealing with that overlap situation.

Since it's segmented topology that is making things more difficult here like Mauro posts a solution is to simplify the topology - here I deleted the segmented faces and built one single surface to replace them, by selecting edges, running Edit > Join to glue them into some new curves, then running Rebuild on those curves to make the to be single segments, then Loft between them. With that in place that sequence you posted above should then fillet more easily:



- Michael

Rebuild is necessary or not ?

Hi Pilou,

> Rebuild is necessary or not ?

Only if removing segmentation in the curve is needed. So for doing a loft for example you want the loft to be in one piece and so you need to rebuild it so the curves are made up of one segment instead of multiple sub segments.

2-rail Sweep operates a bit differently with segmented rails and automatically merges tangent rail segments together into longer rail segments.

- Michael

wow thank you for all the feedback chaps, and also apologies for digging up that old fillet chestnut.

Interestingly, I've not used the 2-rail sweep method before (usually I just loft two curves).


Avoiding segmentation seems to be the key, but it happens to easily it's a bit frustrating. If you look at the original model attached and start diagnosing it by selecting naked edges, individual edges etc it all looks, well, pristine. (I did say "looks" ;) )

It's not until we start adding fillets, or doing a shell operation that problems become apparent as it all goes to Sh!!@

Is there any other methodology for diagnosing problem areas before taking a surface further towards the end result ?

Oh dear.
While the fillet works fine (with rebuild of joined curves and 2-rail sweeps, yay) now the fillet operation has decided to do an unwanted "cleanup" of the rest of the surface.

Hehe.. I swear I'll never feed the fillet function after dark, or let it near water again.

Hi Rico,

> Is there any other methodology for diagnosing problem areas before taking a surface further towards the end result ?

It can be good to view it with a high detail tessellation to see if it's got any weird lumps or creases in it.

To do that, set up a shortcut key with this as the command part:
SaveAs c:\test.obj

Then when you push space you'll be exporting to a temporary .obj file - crank the slider all the way to the right and choose "Display shaded" and zoom in a ways to look at your surfaces.

- Michael

Hi Rico,

> Oh dear.
> While the fillet works fine (with rebuild of joined curves and 2-rail sweeps, yay) now the fillet operation
> has decided to do an unwanted "cleanup" of the rest of the surface.

It's built into filleting that it tries to remove "topological edges" from the model if possible, which means it will try to merge 2 coplanar plane fragments into a larger plane.

In MoI v4 I can see about disabling that but for now there isn't any way to turn that off, sorry.

- Michael

>To do that, set up a shortcut key with this as the command part:
>SaveAs c:\test.obj

Superb tip.. thank you Micheal

>It's built into filleting that it tries to remove "topological edges" [SNIP]
>In MoI v4 I can see about disabling that but for now there isn't any way to turn that off, sorry.

Ahh it's good to know I'm not just going mad and seeing things. (joking aside, was just wondering if I was missing an option)
Thank you again