topic Re: Invalid closed loop in Inventor Forum

Invalid closed loop

trishark78 — Fri, 30 Sep 2016 20:56:09 GMT

My students and I have run into this problem repeatedly with Inventor 2017 but not with previous versions. Here's a simple example.

I've created this sketch. I began with the center point circle and its dimension. Added the top line, tangent curve and bottom line ( make sure the lines were coincident with the circle. Then horizontally aligned the center point of the curve with that of the circle and added the tangent between the line and the circle. Lastly added the 3" dimension. Perfect, we have a nice simple sketch that is fully constrained that includes two closed loops. I even ran Sketch Doctor on it to ensure everything was fine.

The next step is then to extrude the shape.

As you can see by the color of the lines, Inventor is only finding one valid closed region. Super frustrating!

So here's the crazy part. I exit out of the extrude command without extruding anything and return to the sketch environment, remove the tangent constraint and move the lines so that they are not longer tangent to the circle, and my sketch is not fully constrained.

Now when I go to extrude the feature, I have to valid regions!?!

At this point, I symmetrically extrude the right part by 0.5"

OK, so that worked, but it still isn't shape I need. With the extrusion in place, I edit the original sketch and add the same tangent constraint that previously removed and finish the sketch.

The extrusion updates and appears as originally intended.

Clearly this is a very simple example with a simple work around, but I haven't seen the issue in the past and have worked with each release since 2009.

Is this a bug in 2017?

Re: Invalid closed loop

TheCADWhisperer — Fri, 30 Sep 2016 21:29:07 GMT

One simple work-around is to create a sketch slot and then sketch the circle overtop.

This is probably faster with fewer clicks anyhow.

Re: Invalid closed loop

Anonymous — Fri, 30 Sep 2016 21:29:55 GMT

I have had the same issue trying to select the proper fufure.

charlie

Re: Invalid closed loop

trishark78 — Fri, 30 Sep 2016 21:55:54 GMT

This is true and I sure do love that slot tool. I've been playing with it for a while and have found several workarounds and as I said this was just one simple example that I though together to illustrate the point but I have run into it often with parts of varying complexity. For me, it's just an annoyance that I had never run into with previous releases. The real issue/annoyance comes when I'm working with first time users, high school students. I am constantly trying to get them to work simply and efficiently, and to learn to troubleshoot problems as they come up so that they can learn how to avoid issues in the future and have a more thorough understanding of what they are doing. Workarounds are fine when necessary but if a small change in approach can be implemented to avoid the issue in the first place, then the workaround is unneeded. For example, Inventor doesn't seem to like it when you draw overlapping shapes. You aren't always able to select all of regions that common sense or geometric proof would indicate are closed regions. By making use of construction line and/or not drawing overlapping line is a simple change in approach that eliminate and problems. In this case, I haven't been able to determine cause to the problem and I haven't had the issue with prior releases, I thought it might be a bug.

Re: Invalid closed loop

mercerc — Tue, 04 Oct 2016 17:09:52 GMT

Hi,

Is this a bug? Without unloading R2 or SP1 I couldn't tell. As you can see in the video I couldn't repeat the issue I did, as you can see auto project some points. Please review the view and see that your system has R2 or SP1 applied.

Let us know your results.

Re: Invalid closed loop

trishark78 — Tue, 04 Oct 2016 17:33:26 GMT

Here is what I'm running:

From the video, it looks like you did repeat the issue. When you extruded the shape, you were given only a single closed loop, which Inventor automatically selected. In the sketch as drawn, there should be two separate, extrudable closed loops.

Re: Invalid closed loop

JDMather — Tue, 04 Oct 2016 17:49:15 GMT

@mercerc wrote:

.... As you can see in the video I couldn't repeat the issue....

Actually, your video does repeat the issue.

For the Extrusion you should be able to select either one of two (actually 3) closed areas.

1. The circle by itself.

2. The "slot".

3. The "slot"-circle.

Re: Invalid closed loop

blair — Tue, 04 Oct 2016 18:57:30 GMT

I am current on all SP's, Updates and R2 and the issue is repeatable. With two closed loop regions, Inventor selects the whole region. You don't get an option.

Re: Invalid closed loop

mercerc — Wed, 05 Oct 2016 18:05:39 GMT

Hi,

My bad, thanks for the correction on the issue. This issue (not distinguishing multiple profiles) has been reported earlier to us and will be corrected in an up coming release.

http://knowledge.autodesk.com/article/Inventor-2017-Does-not-recognize-the-Closed-profile-in-inventor-2105-and-2016

Re: Invalid closed loop

trishark78 — Thu, 06 Oct 2016 18:11:43 GMT

Sorry to waste everyone's time on an issue that's already been reported. I really did search for it before posting. I guess I need to work on my Googling skills. 🙂