Ductwork Auto-route - no solution found

[colmag6]

I've modelled a couple of duct risers and some branch runs on the floor plates, and have then been connecting the branches to the risers. Nearly all of the connections worked fine, but a few just refuse to work, with Revit telling me "no auto-route solution was found". The attached image shows the ducts I'm trying to connect.

What I don't understand is that I modelled both risers using the same method, modelled the branch runs for one level then used copy/paste to levels so they're all the same, and on the other system all of the connections worked, while on this system some have and some haven't. All are rectangular using shoe-branch connections.

I've tried modelling from the branch to the riser, from the riser to the branch, erased bits of riser and branch and remodelled but no luck.

Any suggestions welcome!

[matt__w]

Are the ducts perfectly aligned? If they're off by a fraction of an inch, Revit will want to put in a transition piece. Maybe that's why you're getting that message?

Matt

[gabecottam428011]

I've seen issues arise with different default fittings. I have found some success in changing the default "take-off" to the standard one to make the connection - and then changing it after the fact.

[colmag6]

Thanks guys.

I've checked the ducts are aligned, which they are, but still no joy. Can't even draw starting from the riser.

If I change the connection type from shoe to tee it works (see attached), but I can't figure out how to change this type of arrangement back to a shoe...?

[elaforge]

I can't figure out how to change this type of arrangement back to a shoe...?

You should be able to select the "straight" fitting and change it to a "shoe" fitting up in the Ribbon where the "drop down" is with the different types of take-off fittings that are loaded into the project.

However if you are using the "shoe" fitting from the Imperial Library I do notice that it is not listed in that drop down even though it is loaded into the project. Not sure what is going on with that there.

[gabecottam428011]

If I change the connection type from shoe to tee it works

I don't think you can change from a TEE to a TAP without deleting the tee fitting and starting over.

You should be able to change from the default straight tap to a shoe tap easy enough though.

[colmag6]

Thanks again for the input.

I'm modelling using metric families, and have tried changed the duct type to use the simplest tap I can find, but the auto-routing still fails.

This model is a test model prior to going into our first Revit MEP job, and I'm wondering how commonplace this type of routing failure is?

If I was asking it do something complicated it'd be OK, but it's managed to do pretty much exactly the same thing 6 times out of 8, but the last 2 just won't play, and this kind of lack of consistency is worrying.

[gabecottam428011]

It's not uncommon to get an error, but it is rare to have such a persistent error.
Without being in the actual model - I can't think of anything else to try.

[jason.martin]

Try using connect into rather than modifying the duct or maybe trim. Sometimes they can find solutions when normal connections can't. Otherwise, can you post the file?
jason

[colmag6]

In cleaning this up to upload, I removed the arch and struc models, and after that one of the connections decided to work. Still one that refuses to work though... file attached.

The dodgy connection is on the "first floor".

Thanks.

[gvluisi]

When I edited the shoe branch fitting and changed the tap type from perpendicular to adjustable it worked...kind of, it sloped the duct but that was easy to fix.

[gabecottam428011]

Still one that refuses to work though...

I copied all the ductwork out and pasted into a blank project with no luck.

But i deleted the vertical 400 x 600 and dragged the 800 x 400 down to the 300 x 500 and then connected the horizontal 300 x 500 into the vertical 800 x 600 and that worked just fine!
then I split the vertical 800 x 600 and changed that section back to 400 x 600...

Shouldn't have to do that much work around...
But anyone who has worked with Revit knows that the instantly in REVise InsTantly is open for debate.

[colmag6]

Sorry it took a while to reply, got bogged down in a project. Thanks for all the input again, the deleting, streching, connecting and modifying worked (at least initially - the duct system is still a bit fragile!).

Looking forward to modelling an entire building, as fast as we could do it in AMEP, CAD-Duct or 2D!

[lcchvacr]

hello Colmac. to a simple solution to this case, we can use a support bracket of the type L-shaped plate, this can be placed at the base of the ducts in the slab serving as supports and fixed at each floor slab., bad this case is not necessary to use it as a family, we can instead use the design mode in place. What would you think?
My sharing helps you?
lcchvacr

[colmag6]

Hi lcchvacr,

I'm sorry but I don't understand what you mean. Could you post an image please?

[zbrown]

I have found that when I get this error it is either because they are not perfectly aligned which has been mentioned already or there is not enough space to create the fitting. In the past I have been able to get around obnoxious fittings like this by separating the two ducts involved and connecting them and then reconnecting them to the original duct work. This is a work around but I have found it very useful when Revit is being stubborn.

[ckidd]

I received the
ERROR: No auto-route solution was found
while trying to the Round Take-off - Shoe fitting. Everything aligned, straight taps still work, etc. I'm not sure this applies to OP, but here is what I had to fix:

After clicking 'Duct' in the ribbon, I clicked 'Type Properties'.

System Family:Round Duct
Type: Taps

Under the 'Fitting' Parameters, 'Tap' was set to 'Round Takeoff: Standard'. After I changed to 'Round Takeoff - Shoe:Standard', Round Duct now taps into my rectangular branch mains using the 'shoe' takeoff (although it usually comes in backwards). I have to rotate the fittings 180 most of the time, but that's an easy fix.

I'm still unsure how I was able to connect the fitting to duct several times, then not able to the next day until I changed this specific value.

[Jrobker]

(although it usually comes in backwards). I have to rotate the fittings 180 most of the time, but that's an easy fix.

Rather than fixing it you can avoid it.

As you model the duct from point A to B that will be the direction of flow, A to B. Your HET fittings will face the correct direction.

[ckidd]

Thanks, I remember learning that there was some significance to which direction you draw duct in my first MEP class.

I thought if I connected the duct to equipment, and capped the other end of the duct, that Revit would figure out the correct direction of flow. Not the first time I've guessed wrong ;)

Also, in a long run of duct, I've probably drawn the duct in several pieces, some with the direction of flow, some against the direction of flow (and some copied and rotated). After they are all connected, I'm not sure which direction Revit will decide is the direction of flow; is there a defined method that Revit uses to decide? Do the other sections of duct take on the properties of the first piece drawn, the first piece connected to the rest of the system, or does each leg of ductwork maintain the flow direction properties assigned when it's first drawn?

Also, while my round and flex duct are both set to use the high efficiency takeoff, the takeoff inserts backwards for round duct, but forward (with direction of flow) for flex duct. :screwy:

EDIT: the attached image shows what I'm talking about. I started with 12x12 at the top left, then made a 'U'. A-B-C-D:
AD
BC

Then, I connected (2)10" round, and (2)10" flex. The Flex is connecting with the direction of flow, the round is opposite.

EDIT2:
I thought the connectors were just coming in backwards for round duct, but now I have another inconsistency. Attachment 2 shows the order the branches were drawn in, one after another. How was one tap was able to go with the flow, but not the others?

[pdellarte]

HAS ANYONE FOUND A SOLUTION TO THIS PROBLEM?
HALF WAY THRU PROJECTS I USUALLY RECEIVE THE SAME ERROR.
THE ONLY WAY THAT I CAN CONNECT THE DUCTS IS TO CHANGE THEM
TO RECTANGULAR DUCTS WITH TEE CONNECTIONS, RATHER THAN TAPS,
NOT SOMETHING THAT I WANT TO DO. I HAVE CHANGED MY DUCT DEFAULTS
UNDER MECHANICAL CONNECTIONS TO NO AVAIL. "CONNECT INTO" OR DRAGGING
THE DUCT DOES NOT WORK. WHAT GIVES?