I would really appreciate any advice on how to fillet this. I need the fins rounded. Nothing seems to works. Any tricks? tips?

If you post the .3dm file we might be able to help. It's a bit difficult just looking at the jpg. With fillets, it's often the sequence you use and at which point in the modelling. You need a filleting strategy.

Hi beanworks - is it possible for you to post the 3DM model file instead of just a screenshot? It's much harder to analyze and examine geometry with just a screenshot.

My best guess from your screenshot would be maybe some difficulty in this area here:



If I had the model file to examine, I would probably start by looking in that area to see if there is possibly a little shelf in that spot - if there are any little surfaces in those areas then the fillet will be limited to whatever size the little surfaces are.

Also it could help to make the outside pieces there be made up of one single big surface instead of separate ones - it's usually easier on the filleter if pieces that look like they come from one cylinder like that actually are just one face instead of split into multiple separate pieces.

Also I would closely examine the top surfaces to see if there are any small edges or faces along any of those areas too.

- Michael

here ya go. Thank you!

Hi beanworks - so that's really quite a really complicated job that the filleter would have to do there, particularly on the bottom part where there is a complex corner area here:




I'm not sure that the fillet engine is going to be able to figure out how to put in a corner patch in that area that has pieces that are opposite facing all connecting together in that spot.

Also right near the same area, the edge here:



The 2 surfaces that meet there are pretty small and come to a narrow point - there is not much room available there to place fillet, even one of a pretty small size is going to try to eat away an awful lot of area out of that little narrow wedge there - so that kind of shape and complexity is probably going to prevent the bottom assembly from being filleted in MoI at least, possibly another CAD system that has a more advanced fillet engine might be able to deal with it better.

The top part I'd say has a better chance, I'll take a closer look at what you might need to do to get the top part filleted.

- Michael

And seems very more easy to fillet just one blade and replicate it after ;)

So on the top piece a few various things that I'd probably do to try and simplify the model would be to eliminate fragmented pieces and try to replace them with some larger surfaces, like for example here where there are 2 separate faces:




I deleted those and then constructed one big cylinder surface like this:



Then trim that bigger surface with the other part to get just one face for that outer side wall part:



Anything you can do like that to simplify the edge structure of the model and make for fewer junctures where there are many edges radiating out from the same spot will tend to help with filleting.

Here's another area with some extra edges that were left over from the seam area of the original revolved base model:



Those can be eliminated by deleting those little faces there, and then replicating the surfaces from an adjacent piece that did not have the original seam running through it over. I did that by using Copy/Paste to duplicate those other surfaces, then using Rotate with an angle of -360/9 to bring them over and then joined them in place.

Then another problematic thing for filleting is when you have 2 surfaces that come fairly close to being smooth to one another but actually meet in a shallow angle instead of being either distinctly sharp or fully smooth.

You've got a situation like that in this area here:



Those pieces are not smooth to one another, they meet in a shallow angle - anything that meets in an angle will then make for a more complex fillet juncture between them, and when the angle is particularly shallow the juncture gets hard to deal with because it becomes a kind of tiny slivery thing.

So you want to make that area either smooth or more distinctly sharp before trying to fillet the blades, one way to smooth it out is to select these edges here:



And then do a fillet of a fairly large radius (larger than you will use for the blades later) to make those spots actually smooth (here with radius = 0.5):



So with those tuneups in place it looks like the bottom part of the blades there will fillet ok now, there is still some difficulty with the top piece, I'll take a look there next.

I've attached the 3DM model file with the above adjustements made, it's only a fragment of your original model.

- Michael

So another problem area that's probably causing some of the difficulty with filleting the top edges is this area here:






The thing that's bad about that structure is that it makes for a pretty small sized edge fragment up here at the top:




The filleter is going to try to build a separate little fillet segment for that edge and try to figure out how to splice it in with the others, and it's going to be compounded by the 2 surfaces that meet at this edge here:



Those surfaces are another area where they are not quite smooth or sharp to one another - they are close to being smooth to each other, but they're about 1 degree off from being tangent with one another - that's enough to possibly make the filleter have to try and build a corner juncture patch between fillets that meet there.

You want to make sure that things like that in your original curves are either smooth to one another or sharp to each other, you don't want to just make things look like they are smooth to one another without actually using snaps or fillets to do it, because that ends up with this type of shallow angle situation which will then make things difficult for the filleter later on.

Ideally you'd want to get the curve that was used to cut or extrude those pieces to be all one single segment so that the extrusion was all one single smooth face instead of 2 different face pieces with one small slice at the end like that.

That's kind of difficult to fix in the already finished model, you might need to go back to some of your original curve structure to fix that.


Then the other potential thing that may also be stressful on the filleter is having surfaces come to a "needle thin" type end like this shape on the inner hub:



I would not be too surprised if that shape there would be causing some other problems for the filleter as well.



The filleter has a complex sequence of tasks that it needs to do, like generate surface offsets, intersect the offset surfaces, generate fillet rails, generate fillet surfaces, extend and intersect fillet surfaces between each other on sharp corners, trim them back, and put in corner patches between areas where there are holes between fillet surfaces.

It doesn't take too much to make things complicated for any one of these stages, a lot of times things that involve little slivery pieces will make things hard to intersect and figure out.

Sometimes it may be that you've got some slivery pieces in your model, but also having things come close to being smooth to one another but not quite will implicitly generate slivery corner patch pieces because 2 fillet pieces will only exactly meet up to one another without any corner patch needed when 2 edges are smooth to each other where they meet up.

- Michael

I would definatly cleanup all that fragmented stuff mentioned.



It wont take much. Michael points out how to do some larger areas fast.

Thanks so much for the help!!

You can also use the Freeware beta Autodesk 123d for extrem Fillets.

Yes I use that app from time to time myself as well.

Peace,
Rich_Art. ;-)

Wow, thats pretty amazing.

thats awesome. what file format did you use to open it in 123d?

Moi Export Step or SAT

did you edit the model? I keep getting a fillet failure.

Most it`s a Scale problem, when you export "step" in your scene you can try fillet units between 0,1 and 0,005.

Or you can try to edit it with press/pull. Press or pull a patch a little bit: (0,0001).
And Try to Fillet again.

Here are two Examples from my YT cannal

http://www.youtube.com/watch?v=rtzDS9_VYSY&list=UUGjMjuL1Njc7XJlalQMJJIQ&index=7&feature=plcp

http://www.youtube.com/watch?v=1fSk2RWv-IQ&list=UUGjMjuL1Njc7XJlalQMJJIQ&index=6&feature=plcp

One thing that helps with fillets, is to avoid unneccessary edges in your construction. I find that when I have built a curve structure, it is often best to join it, then carry out a rebuild on it to make one single curve. The original joined curve will create edges if you, say, extrude it, where the joins were. The rebuilt curve won't.