Fillet Edge Problem - Rhino Beginner

I find it works best to split closed clamped surfaces into 2 pieces. That avoids all problems that structure can cause

and however you arrived at this opinion this is certainly not what our discussions is about or was, since you seemed to have ceased throwing more unrelated and specious theories about others into the lets say monologue.

Jim, I found your example to be helpful. Thanks for explaining it. —Mark

Absolutely. If one is interested in proper data that is good for more than casual renderings and hobbyist “maker/crafter” endeavours, quality is paramount - and interactive modelling/analysis tools that enable the designer to get there in a repeatable and reliable fashion.

Yes, I too noticed that sometimes fillets on revolution surfaces (usually built by a tapered extrusion) give problems.
As sometimes also do extrusions with kinks, i.e. extrusions from a profile composed by arcs and straight segments.
On the other hand, such single surfaces work much better with FilletEdge: much more chances to have the edges that FilletEdge requires, I mean edges connecting the ‘right’ couples of surfaces …
I wish I could easily switch between single-complex surfaces and multiple-simple surfaces, but a reversed DividAlongCreases doesn’t (yet ?) exist … :slight_smile:

FilletEdge: doesn’t seem to work very well with the file I posted.

You can use MergeSrf [Smooth=No] but you can only add one surface at a time and they have to be untrimmed. You can save the trim boundary and redo the trimming after merging.

I know it does not always work fine …
But I often work with shapes made from hundrends of surfaces, and when FilletEdge works on sequences of, say 50 or 100 edges, it saves a lot of time. Also because trimming the original surfaces after making fillets with FilletSrf can require more time than filleting at times …
So I usually try first FilletEgde.
If it works, OK.
If it almost works, I keep the good fillets and redo the bad ones by FilletSrf … and then manage to trim somehow …
Last resort: good old FilletSrf plus trimming … When I’m lucky, joining the fillets into a polysurface and using its border to trim the original polysurf works. :slight_smile:

Yes … this is the long command sequence that I’d like to avoid …

Thank you !

Usually if the underlying surfaces are of good quality and good continuity, then you can make complete joined fillet loops and do the trimming with one or two clicks of the mouse using the fillet surfaces as cutters.

Doing that often makes trimming a difficult task. What is saved from the filletedge operation can make trimming
close to impossible. That may be because some edges are out of tolerance.

Ah, OK.
Unfortunately there is no way AFAIK to know where the trim fails, when trimming by long fillet loops …

Thanks

I find that I usually discover why in subsequent modeling operations.
For instance if the subsequent joining fails somewhere that’s where the trimming failed.
I also have found that when the trimming doesn’t fail that’s a pretty good indication that things will go smoothly going forward.

There is one exception to trimming with fillet loops and that is when the loop goes all the way around a planar surface. For some reason Rhino can have trouble with trimming that. I just sidestep the problem by making a planarSrf and deleting instead of trimming the flat surface.

Yes, Rhino sometimes seems to have some problem with degree-1 surfaces, and also at times with rational, degree-2 surfaces.
Fortunately, for planar surfaces we always have two options. :slight_smile:
… And can do what you just said.
I also sometimes do the opposite: drawing a plane then trimming when PlanarSrf fails … :smile:

BTW Talking about trims … I don’t know why, but often trimming by the edges works when trimming by the surface fails … :confused:

If we are talking about trimming with surfaces made by filletSrf , its only planar surfaces that I have seen trimmed incorrectly.

Failing to trim when the cutter is a fillet loop is different matter. As I said if the underlying surfaces are good quality that almost always works. I like to use offsetsrf as a way to check quality. Explode, offsetsrf, join and then check for naked edges and ugly surfaces. If everything looks good then undo and start with filleting. The offset amount should be a couple times larger than the fillets to be used. Avoiding surfaces with multiple knots also helps. Zebra analysis also is a good analysis tool.

Thanks for all your suggestions, Jim !

… Although here I need no particular surface quality.
I work on thermoformed plastic trays. Usually just simple profiles extruded tapered, planes … and a lot of fillets to be able to easily offset the thing to get a constant thickness.

Only need for (almost) closed solids is for suppliers with weird CAD-CAM systems, or clients with weird requirements to load the models onto their dump solid-only systems … :wink:

I mostly need speed here … I have to draw simple shapes, but soon …
I admit this is not a work for Rhino IMO, but that’s what they gave me. :wink:

Best regards.