Fillet or Face Blend on Icosahedron

l_m724

Hi guys

I'm designing a 3D-printable watering can using a Icosahedron as the main body. Unfortunately, i got huge difficulties rounding the edges. I want a slight Fillet or Face Blend to improve printability and make the handle more comfortable, but i'm unable to apply it to some edges. I get a range unhelpful errors like "Failed to blend faces" or "Failed to filet selection" "Selection of edges at vertex is too complicated for fileting", and i can't recognize from the preview, where the issue is coming from.

Can anyone explain to me, why it is so hard to fillet the edges of the icosahedron? :)

https://cad.onshape.com/documents/a4924dd6214d808fad09e12d/w/90131a7713b3a74bc2bdf488/e/fc8f260d15c8a72a8828952c?renderMode=0&uiState=671a2961feb57e55b4563a84

MDesign

When your looking at the preview. look for red highlighted areas for potential problems. You may have to do some of it in a series of steps rather than all the edges at once. I did a lot of them with fillet inside and out shown in pic, but I ran into some inconsistencies in geometry somewhere where it would fillet things the differently in one spot when it should be identical to another spot. Not sure what was going on there. depending on target radius you may have to fillet certain thing before others so you don't end up with self intersecting problems.

MDesign

Also you could of simplified your base object creation with just polar arrays and mirror features. Once the first loft triangular pyramid was done. no need for any more sketches and extrusions/lofts. Here's an example of just 3 fillet features getting all the edges.exterior, interior and then the opening edge.

MDesign

It is interesting there is a place here where the handle sketch 7 doesn't line up perfect and not fully constrained. but when boolean 6 gets applied that cleans up. I wonder if this isn't was I'm seeing in the inconsistent fillets for similar parts of the objects.

_anton

I haven't yet published this feature, but it could further simplify your project: https://cad.onshape.com/documents/01168ba15e051e7a318549cf

l_m724

Alright thanks for the help guys. It seems like it is (again) mostly trial and error with the filleting for my model. To be honest i most likely didn't model according to best practice and kinda winged it. Maybe that the reason for this weirdness and inconsistencies.

EvanReese

@l_m724 This is a challenging shape.

Fillet can struggle with intersections of a lot of edges. I was able to get it to fillet, though I'm not 100% happy with some of the artifacts (like the wavy surface break where the spout meets the body). To get this where I'd like it I think I'd end up doing a lot with surfacing tools and it would be a pretty different approach. Here's this one anyway. I was able to shorten the feature tree considerably. A few other notable things I did:

1. For starters there's a Polyhedron custom feature already, which will save you making the icosahedron yourself. ( @_anton your WIP looks awesome too!)
2. I used my custom feature Selection Fillet to batch some of the selections, but for that reason, I wanted to fillet before the Shell feature, but also not bother shelling with the fillets, so I made my own "shell core" using another method, which I later subtracted. You could also just use the native Fillet feature.
3. Keeping some bodies separate to fillet first and boolean them together later can be a helpful strategy sometimes.
4. I used a variable called #radius so that I only need to change it one place if I want to update the fillet radius. In your model, you had 40 fillet features, so this would be even more valuable if you're doing it that way.

Feel free to ask questions.