Hey guys, for some reason I can never get a 3D software to do fillets correctly, nicely, or at all. With Moi, fillets work and don't, why I'm not sure, here's an example of where I can't fillet anything. ):

Hi Shazbot, it's better for filleting to not have any unnecessary extra edges in your objects. For your case here that means you don't want these edges here:



It would be much better in your case here if those cylinder pieces sticking out were made up of just one single cylinder surface rather than fragmented into a couple of different sections.

The reason why it gets hard for filleting is at juncture areas where many fillet pieces are coming together and need to be trimmed with each other and possibly have a "corner patch" filled in, like in your case you have juncture areas here with 5 edges coming out of that point with many of the edge nearly tangent to one another where they meet up:




That kind of "nearly tangent" geometry also makes things difficult for filleting as well because when 2 surfaces are nearly tangent to one another when they get intersected with each other the intersection is kind of more of a fuzzy region of overlap rather than a distinct intersection curve.

So I'd probably try to replace those fragmented cylinders with just one cylinder surface and that should probably help a lot. You also may want to make the base shape for something like this to be made of one side profile that then uses Construct > Revolve, rather than lofting through many different sections, it's just a bit easier to control it when drawing just one curve for the revolve.

- Michael

Also the little face at the very top and also the small amount of space in the bottom areas here will limit the amount of space that it will be possible to put in fillets as well. Fillets won't work very well if they would have to overlap each other to fit in small areas.

- Michael

Thankyou Michael, that makes a lotta sense, I'm use to a 3D program doing it regardless whether it will work or not with intertsecting edges, etc. This should help me a lot, thanks again! (:

Hi Shazbot, I've attached here a 3DM file with a tuned up version of your object with those cylinders simplified, and also the little top face removed (I duplicated the edge curve you had and edited the top of the curve and did a revolve to make a smooth tip), and this should fillet now, it doesn't have the difficult multi-edge juncture areas that you had in your previous model.

You will be limited to a pretty small fillet radius though still - it won't work to do much more than about 0.06 units for the fillet radius, because there is not enough room to fit a fillet larger than that without the pieces running into each other in these tight areas here:






If you wanted to put on a bigger fillet than that, those cylinder pieces would need to go up a bit more and also probably stick out just a bit more, otherwise there is not enough room for the fillets to actually fit in the space you've got there.

- Michael

Holy cow! Thanks Michael! It never ceases to amaze me how helpful this forum is! Thanks for your time, every day I'm understanding Nurbs a little more, although easier, it requires you to think in a different perspective and as always practice. (:

Hi Shazbot, no problem I hope that helps!

> Thankyou Michael, that makes a lotta sense, I'm use to a 3D program doing it regardless
> whether it will work or not with intertsecting edges, etc.

You mean doing an edge bevel in a polygon modeler? Those do a pretty different kind of thing than what NURBS fillets do. The NURBS fillets are a really precise arc shape.

The NURBS fillets are formed by a quite complex process of generating offset surfaces , intersecting those offsets, that then builds some guide rails that are used for generating fillet surfaces, the fillet surfaces are extended past one another and trimmed with each other and then possibly corner patches added in for areas where multiple fillet pieces were coming together, and then the whole model is also trimmed to cut away the extra space outside of the fillets.

It's a tremendously more complex process than just smooshing polygons around...

- Michael

I see, thanks for info!