Fillet command is driving me insane

[nate.lazenga]

I have been fighting a model for a few days and cannot come up with a solution. I have some offset features that I want to create a smooth transition (5mm into 3mm). The transition worked on one of them but not the other 3. I don't know what else to do. 

I continue to get the error "Error: The fillet/chamfer could not be created at the requested size.
Try adjusting the size, deselecting some of the edges (try disabling Tangent Chain), or using multiple separate operations." I have looked at a number of other similar posts and cannot find a solution. Please help. 

https://a360.co/386wvqZ

[gamelife4dns]

Interesting model, with challenging curved surfaces 👍
Try with smaller fillet radius values, as the error msg suggests.

[nate.lazenga]

That is not what I want. It forces me to use 0.5mm radius to calculate.
this does not give me the look/feel/function I want. Are there any
other options?

[jeff_strater]

I'm not 100% certain that this is your problem, but I do know that Fillet can be sensitive to this condition.  The difference between the fillet that succeeds and the one that fails is the edges on the successful one are tangent continuous.  You can tell this because if you invoke Fillet with chaining on (the default), it selects the entire edge chain:

where the edges of the one that fails are not tangent continuous:

I know that fillet can be susceptible to these "near tangent" edges.  I don't know why - that involves math that is way over my head...

I don't have time to investigate your model, but try to go back and figure out why these edges are not tangent, see if you can fix that, and it might help.  No guarantees, though.  Fillet is not a magic tool - there are limits to what it can do, and there might be other problems here

[gamelife4dns]

I understood what you want. I was suggesting to try smaller values and see if they pass. Increase values progressively and look for the limit that stops working. This might help you understand what could be wrong.

Also, Jeff raised a good point about continuity of the edges chain.

[gamelife4dns]

There are some weird edges on your design, they look like chamfers and reliefs. See the attached picture to see where, and zoom on your model.