Fillet on Tangent Circles Error

[ibanovBT6ND]

I am trying to fillet the sharp edges of a case. The fillet works on three of the four edges, but not on the last one. I am not sure why I am getting this error for this edge, when it works on all the other edges. The error I receive states "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 tried adjusting the size of the fillet, deselecting the edges, and creating multiple fillets. However, I cannot find any workaround. This issue only happens on this one edge. Any advice on fixing or diagnosing this issue would be appreciated. I have attached the source file and the screencast below. Thank you!

[g-andresen]

Hi,

0,99 mm works!

günther

[ibanovBT6ND]

Thanks for noticing that! I have made that change for now. I am not sure that this is a real solution, but if I do not get any better response, I will mark yours as best. I really want to know what I have done wrong in my file to cause this error, so that I do not repeat it in the future. I appreciate your help!

[jhackney1972]

You went through a variety of sketches to get to the feature you are filleting so I am guessing it is a build up of calculation error that causes one of the fillets to fail.  As @g-andresen points out, .99 works and so does .9999 which kinda shines some light on my theory.  Probably if you modeled it using a different sketch routine, it would not be an issue.

[ibanovBT6ND]

So, in the future, would it be better to draw out all of the sketches on one plane, and then extrude all of the layers from one sketch instead of three? Thanks for the input!

[jhackney1972 · Accepted solution]

No, that is not my theory.  Fusion 360 uses some calculation engine precision that just happens to add up to create an error in just this feature.    You have to admit with a 0.0001 mm (0.00000394 ") between the feature failing and succeeding has to be related to the calculation engine precision in some way.