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Minimum segment length violation in tube & pipe runs?

15 REPLIES 15
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Message 1 of 16
hheng1111
3554 Views, 15 Replies

Minimum segment length violation in tube & pipe runs?

I keep getting this minimum segment length message after running tubing routes. I've already configured the tube style and entered the minimum length I want. I place tube fittings before I run tubing, so I don't include fittings/couplings in my tube style. The lengths of the segments are equal to or longer than the segment rule I entered, so I'm not sure why I'm getting this error message. I also get a message saying that a segment will violate the rule once fittings are placed, even though I've opted out of using fittings in the style. To get around this error I've been having to go into each route and edit the sketch to make the problem segments longer. Does anyone have any idea how to fix this? Thanks in advance for the help.

____________________________________________________________
HP Z400 Workstation
Intel Xeon @ 3.33GHz
12.0 GB RAM
Windows 7 64-bit
Inventor Pro 2015
15 REPLIES 15
Message 2 of 16
hheng1111
in reply to: hheng1111

Anyone?
____________________________________________________________
HP Z400 Workstation
Intel Xeon @ 3.33GHz
12.0 GB RAM
Windows 7 64-bit
Inventor Pro 2015
Message 3 of 16
cbenner
in reply to: hheng1111


@hheng1111 wrote:

I keep getting this minimum segment length message after running tubing routes. I've already configured the tube style and entered the minimum length I want. I place tube fittings before I run tubing, so I don't include fittings/couplings in my tube style. The lengths of the segments are equal to or longer than the segment rule I entered, so I'm not sure why I'm getting this error message. I also get a message saying that a segment will violate the rule once fittings are placed, even though I've opted out of using fittings in the style. To get around this error I've been having to go into each route and edit the sketch to make the problem segments longer. Does anyone have any idea how to fix this? Thanks in advance for the help.


I believe that if a fitting placed in your route will cause a length violation, you will get this message even if you have specified no fittings in your style.  Often where i run into this is with elbows (rigid piping) that cause the resulting segment to be too short.  You say you place fittings before you route?  Can you describe your workflow in more detail so I understand?

Message 4 of 16
hheng1111
in reply to: cbenner

The vendor we get tube fittings from provides 3D models for download. I have these models saved to a library and place those into assemblies whenever I need them. So I'll place a fitting at one point, another at a second point and run the route from fitting to fitting.
____________________________________________________________
HP Z400 Workstation
Intel Xeon @ 3.33GHz
12.0 GB RAM
Windows 7 64-bit
Inventor Pro 2015
Message 5 of 16
cbenner
in reply to: hheng1111

So, you place your fittings with standard assembly constraints, and the route between them?  Are you aware you can probably author and publish these to be used inline as part of the Tube & Pipe module?  Regardless, I still can't figure why you're getting segment length violations.  Is it possible to post screen shots or a small assembly that exhibits this behavior?

Message 6 of 16
hheng1111
in reply to: cbenner

I just started using the tube & pipe environment recently, so I haven't gotten that far yet. I will definitely look into it though. I attached files for a very simple assembly and also screenshots of my style rules and the length of the segment giving issues. You'll see that I constrained my fittings first and then ran the tubing.

____________________________________________________________
HP Z400 Workstation
Intel Xeon @ 3.33GHz
12.0 GB RAM
Windows 7 64-bit
Inventor Pro 2015
Message 7 of 16
cbenner
in reply to: hheng1111

Ok, I see now how you are using the fittings, and there is nothing wrong with it.  Since these are end fittings, I would probably do it the same way (with constraints and then routing between them.)

 

Try this:  In your Measure box, hit the arrow on the right, go down to Precision and select All Decimals.  Let's see if this is a rounding issue.  (see my pic).  Maybe that segment is actually .99999999 in, or something like that and Inventor is rounding up to 1 in.  Another thing you could do is manually change the radius of that first bend to 1/2" and see if that solves it.  Just as a test.  I suspect it is a rounding issue.... let's check that.

 

alld.JPG

Message 8 of 16
hheng1111
in reply to: cbenner

The measurement still shows one after selecting all decimals. Manually changing the radius of that bend does fix the problem, but the initial value of 0.625 is what I am needing. The program is following the rules I specified when it's generating the tube path, so it doesn't seem like an issue of how the path is drawn.
____________________________________________________________
HP Z400 Workstation
Intel Xeon @ 3.33GHz
12.0 GB RAM
Windows 7 64-bit
Inventor Pro 2015
Message 9 of 16
cbenner
in reply to: hheng1111

Ok,... I'm running out of ideas (sorry!)... but try this:  Edit your route and make that one inch segment longer than one inch by maybe 1/4"?  It is possible that, since your next segment is not perpendicular to the first, that when the bend id applied the angle may cut away form the 1" segment... even by a tiny amount.... and throw it off the rule.

 

If this doesn't do it.... I'm not sure what to check next.  I can't open your assembly because I'm still on 2013.  But if this doesn't help, I can ask some other folks if they'd take a look at it for you.

Message 10 of 16
hheng1111
in reply to: cbenner

I tried to run a route in the shape of a "U" with all segments on the same plane, but I still get the same error. Increasing the minimum segment length rule didn't make a difference. I really want to say it's an issue with the program at this point, but I have no way of confirming that myself of course. I appreciate all the time you've taken trying to help me out.
____________________________________________________________
HP Z400 Workstation
Intel Xeon @ 3.33GHz
12.0 GB RAM
Windows 7 64-bit
Inventor Pro 2015
Message 11 of 16
cbenner
in reply to: hheng1111

I really wish I could open your files.  Just as an FYI... I have all of my minimum segment rules set to .001, which is the smallest the program will allow.  This gives me the flexibility to determine the minimum segment length on a case by case basis.  That may not work for you in your application... just throwing it out there, but I almost never get violations.

Message 12 of 16
hheng1111
in reply to: cbenner

Yeah, we go by the specs in a tubing manual. It specifies minimum bend radius, minimum segment length before a bend, etc. I just enter the numbers into the style in inventor and let the program run the route. I'm looking to just have it as automatic as possible without me having to go into sketches and change things. I'm sure your way works great, but we sometimes have lots of tubing to run, so It would be nice if this was working correctly.

 

I reinstalled my 2013 Inventor and made the assembly again. The block itself is a little bigger than before, and I added another tube run.

____________________________________________________________
HP Z400 Workstation
Intel Xeon @ 3.33GHz
12.0 GB RAM
Windows 7 64-bit
Inventor Pro 2015
Message 13 of 16
cwhetten
in reply to: hheng1111

I took a look at your files to see if I could figure anything out.  I was baffled at first, as it didn't seem to make any sense.  I adjusted the minimum length until the error went away, and it appeared to start working when the minimum segment length was 0.946.  Once the route was no longer comatose, I populated the route to see if anything showed up.  Sure enough, I saw that the tube sweep doesn't begin and end at the same place as the route 3D sketch.  There is a 0.05323427 gap before the tube actually starts (see the image), and this accounts exactly for the minimum segment violation problem.

 

I don't know why the tube doesn't start where you tell it to start...  I suspect it has something to do with the way the tube was authored, but I haven't figured out how to confirm that.

 

segment violation.PNG

 

Cameron Whetten
Inventor 2014

Message 14 of 16
hheng1111
in reply to: cwhetten

Wow, thanks for the insight. That is odd. Do you think this is something we can fix on our side, or is it up to Autodesk?
____________________________________________________________
HP Z400 Workstation
Intel Xeon @ 3.33GHz
12.0 GB RAM
Windows 7 64-bit
Inventor Pro 2015
Message 15 of 16
cwhetten
in reply to: hheng1111

It's hard to say.  I can't figure out where the discrepancy is coming from.  The size of the gap appears to change if the "Increment" parameter in the tube style is changed, but I've been unable to figure out the relationship.

 

So, barring a real solution to this problem, it looks like you will have to either adjust the values of either "minimum segment length" or "increment" in your tube style, or you will just have to increase the length of your sections of tube so that you don't get too close to the minimum.

 

Cameron Whetten
Inventor 2014

Message 16 of 16
james.bergey
in reply to: cwhetten

I don't know the specifics of your issue, but I know that there is some cases where the threaded pipe engagement specs are considered. So for example the opposite way with maximum pipe segments, I think you need to actually make the max length segment a wee bit less than the one you want to come out. i.e. if you want a max pipe length of 10', you need to account for the thread engagement and set the max segment length to 10' minus double the thread engagement.

 

Sounds to me like maybe it stems from a situation like this.

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