No auto-route solution found and other errors

[micphillips]

I am currently trying to "trim" two ducts at a 45 degree angle. This is certainly possible within revit, although we often get various error messages such as "No auto-route solution found" or "the resulting angle between segments is too great or too small" and rarely we will get the error "Segment is being drawn from the wrong side". I'm very good at troubleshooting Revit's quirks, although we cannot seem to figure this one out.

I've attached some images for reference. In "error 1.png" you can see the operation. I'm simply trying to join the two ducts at a 45 degree angle. In "error 2.png" you can see an example of one of the several error messages received. In "error 3.png" you can see that the ducts of the same type (which does not actually matter) and that they are both supply air and on the same workset and design option. In this particular example I've trying the trim command. I've tried drawing the duct directly into the other one at the endpoint. I've tried copying the ducts out and trying again. I've tried in numerous views. I've verified that the ducts are aligned on all sides (as the ducts are the exact same size, although again this shouldn't matter.) I've even trying drawing brand new ducts.

This is not a detrimental issue considering it will wind up working in a few hours or after a half hour or so of repeating the same troubleshooting steps. It's irritating that I have to waste so much of my companies time to try and do such a simple operation in Revit. This has been an ongoing issue that we tend to spend way more time on than it's worth. It's much easier to simply "show" the segments connecting rather than physically connecting them, but that just leads to much larger issues down the road.

On another note, we have even received this error when just drawning a brand new duct out in space by itself. At times, we've gotten all 3 errors while doing this. 

I know the answer is going to be something like "deal with it" or "it may get fixed later on" but is there a "dirty" fix that can be used until autodesk fixes the issues with MEP or a workaround of some sort? Maybe I'm just doing something wrong, although many people in my organization have the same issues "electrical conduits, piping, ect.) Another common issue that should be address is the wacky transitions that will sometimes be automatically placed when trimming ducts. Either you get a weird offset or a complete unworkable solution.

Update: all routing preferences are set up correctly and our templates have been tested.

[robert.klempau]

Hello @micphillips,

few questions:

1. what Revit version are you using?
2. what are your MEP Angle settings for Ducts and Pipes?
3. Can you upload a exported group with a small duct and pipe layout?

[micphillips]

@robert.klempau

Thank you for your response.

1. I am currently using Revit 2016.

2. I've attached screenshots of my angle settings.

3. I've uploaded a group of some ducts located in our current project.

[micphillips]

Another common issue we have is when trying to trim ducts at a 45 degree angle, we get weird transitions. I've attached a screenshot of the issue. The duct is of the same size and aligned with the duct I am trying to trim.

[fabiosato]

Hello,

I tried to reproduce the error with no success.

Can you post a file with the problematic pair of ducts?

[micphillips]

The error happens at random times, often at unlikely times. Sometimes it's when drawing a brand new duct, and after several repeated attempts, it will eventually work. Same goes for trimming, if I try over and over again, eventually it will work.

[micphillips]

We've encountered the error again. I've uploaded a group of ducts that are causing trouble.

[Anonymous]

Sorry, edited due to wrong profile, see my post below...

[rudi.roux · Accepted solution]

Hi @micphillips, 

Hope you are well. I attached the file again (everything is connected) to go through some troubleshooting. I hope I could shed some light on this matter. 

As you mentioned, other disciplines also face similar issues, electrically the errors which you mentioned is also common when modeling electrical cable trays when bending radius multiplier/s aren't setup correctly or assigned properly under family types etc. etc.

Back to your ducting queries, common issues causing your errors are: 

• Alignment differences between elements. Also, very small level differences. (I picked up on a small difference between your Rect. Duct >> Round Takeoff >> Control Valve)
• When I receive errors as you mentioned, I revert to using the "Drag Nodes" opposed to Trim, I also try dragging the e.g. 30deg duct to the horizontal intersection point, then I drag the horizontal duct to connect with the 30deg duct to complete the run. 
• I generally have two default sections which I use just to check alignment or to do the connections "manually" by means of using drag nodes. 
• I changed your elbow bending radius diameter and tested by changing your elbow default family angles just to check if the result in this scenario would change, but it still gave errors, which then tells me that this is just a case where Revit struggles to understand what needs to happen. 
• This is where workarounds are to be used and to be honest, I doubt that this will change anytime soon as this has been common for years now. 

So the workarounds...

• In this case, I checked the levels and alignment, made a correction, then move the control valve away ( specific measurements, I used 5' ).

Next, draw the 12" round ducting in:

Next, select the control valve and move it back by 5' (Ending in the desired result).

The other ducts, working by means of trimming: (Done by means of dragging nodes, trim or directly connecting results in errors).

Firstly, select the horizontal duct (the one coming from the takeoff). Drag the run back towards the takeoff a bit. 

Next, select the 30deg duct and drag it down until the dashed intersection lines appear.

Lastly, drag the horizontal duct to the connection point of the 30deg duct so that the run can be completed without any errors. 

Just to emphasize the point which I made that Revit sometimes does not understand what needs to happen and sometimes with a similar a scenario, Revit would understand what needs to happen. (Without workarounds) 

I copied the bottom and top horizontal ducts from the above-mentioned example, along with the 30deg duct to give me the sample below: 

(I also created a 45deg duct just for testing)

I used the trim function in both scenarios to complete the connections without any problems. 

To close off, use the workaround of either moving elements away(specific distance), then connect everything and then move the elements back to its original position. 

Secondly, use the drag nodes and try it from both ends/ducts.

I hope this helps! 

[micphillips]

Thank you for the great response Rudi. We have been using the drag node workaround for some time now. We do still get errors, but much less frequently. Moving the elements a specific distance sometimes works, but often also presents an error.

I will mark your solution as the answer, considering the well thought out response and the very useful information, however do you have any idea as to why these errors also show when drawing a new duct out in space? This is a rare occurrence, but a frustrating one nonetheless.

[rudi.roux]

@micphillips, you could check your Ducting Family Routing Preferences and check to see if the Elbow Preferences weren't accidentally changed to "none" or if the radius multiplier within the family type properties(elbows etc.) wasn't set to 10 by accident. 

Also, when drawing a duct run, then stopping and say you start to draw another run from the other side, make sure that your offset as well as your offset in your properties pallet match. I've had similar issues as you mentioned with new ducts, above are a couple of things which I check. It's not common as you also mentioned so I can't exactly remember or recreate the error now, but if you come across it again, feel free to post a sample and then the community could take a shot at it