Closed Loop - Arc to Arc Tangency issue / bug

[ihiengdept]

I've spent quite a bit of time digging into this issue and can't seem to find a solution.  In summary, there seems to be an issue closing a loop when there's a tangency between two arcs of a certain size relationship.  Shown below is what I want to do:

This works just fine, the problem is, I want a larger radius than shown.  As soon as I change it to R1.0, the loop no longer closes.  I've tried all types of sketch orders and constraints that indirectly create the tangency,but always get the same results.  I've even tried larger radii, and then dimensioning them down (making sure that the arc never intersected the second arc twice), but nothing except a smaller radius (as shown) works.

The only current solution I have is to remove the tangency constraint and constrain the radius with a different dimension calculated to be just producing an intersection just short of tangency.  This is time consuming and quite inconvenient.  Feels like a bug.

[JDMather · Accepted solution]

Interesting issue.

Go ahead and extrude with R.5 and then edit the sketch to desired radius.

(BTW - I tried the same steps in another SoftWare and did not see this issue.)

[mpatchus]

Very odd.  Looks like .795 is the largest radius it will accept and still see it as two closed sketch elements.

[mpatchus]

Even odder... increase the dimension to 1 1/2" and it works fine.

[ihiengdept]

BTW, this is all with Inventor PDSU 2014

@JDMather

Thanks.  I thought I had tried that at one point, but I guess not or it was one of my different configurations.  That does seem to work for this case.  I also found another work around after posting.  Since this particular case is adding material, I can change added some overlapping material and that allowed a similar version to work.  

When you say "another software", are you talking about something outside the autodesk realm?  I can reproduce this error starting from a new part.

[JDMather]

SoftWare is my code for SolidWorks.

[ihiengdept]

@mpatchus

Yes. Very odd. I'm inclined to think it's a bug. Perhaps it's related to the rounding errors present in floating point #'s out at the n'th decimal place.

[ihiengdept · Accepted solution]

I submitted this as feedback to Autodesk a few weeks ago.  They've sent a few emails as they've looked into it, but the long & short is that they've entered it into their development system.  Hopefully we'll see a fix in a future release.

Thanks.

---------------------

<redacted>,

This is just to inform you the development team has confirmed this issue I have reported to them on your behalf. Although there is no time table for fix for this issue they will continue to test against the newer builds. They are required to provide a prognosis within the development case. Since this issues has been confirmed we are required to close the support request. If you need to comment the case will reopen.

Best regards,

<redacted>
Autodesk Support Team

[burak.zeybek]

[JDMather]

Not sure why you posted in this thread and double posted here

http://forums.autodesk.com/t5/inventor-general-discussion/open-loop-eror-tangent-to-tangent-pattern/...

I see these as two different problems.

When you attach your file to the other thread (where  it should be) someone will show you the solution.

There is as easy solution to your problem - so I would't call it a "bug".