How to maintain the slope of an entire odd shaped length of ductwork?

[Anonymous]

How do we maintain the slope of an entire odd shaped horizontally (but slightly sloped) length of duct from its beginning to its end?

For instance, we have that length of ductwork, lets say like a "Z" shape in plan, that runs on the upper floor plenum from the vertical duct coming from a floor below to its outlet at the roof.  The duct will have to be sloped at 1/16"/1" (at 1/16" per 1"), since it is for a kitchen hood exhaust, coming from a ground floor.   The location of the sloped duct is sentsitive and critical, since it has to be positioned between the structural joists.

How do we can have the entire odd shaped length, with 90 degree turns, at a constant slope?

Thanks in advance.

[hmunsell]

im not currently at my computer, but you can try to place a reference plane in an elevation at the slope you want, name it, and set that reference plane as your working plane. Then when you place the duct it should follow that reference plane.

[Anonymous]

I was able to create the entire length of the duct on the plenum horizontally and when I click it, its entire length becomes blue manning that the parts are attached well, but the heights do not appear on the plan and neither on the Properties dialog.  

How can I have the height appear somewhere so I could change the height at the beginning and also at the end of the duct system?

[Anonymous]

The reference plane idea seems interesting, will see if I know how to create it with a slope, will keep you posted.

[hmunsell · Accepted solution]

I tried the reference plan option and I was wrong it didn't work :-(.

from what I know you can edit individual elements, but not the whole run.

you can always select the whole run and then just rotate it....

[Anonymous]

I created the ref-working plane with the desired slope and set it as the working plane on the plan.

How do I attach, that is, how do I align the bottom of a duct system to that sloped ref-plane?

Do any body knows that can advise?

[Anonymous]

It took some doing to do it by selecting the whole run and rotating it, but it worked.  Thanks a lot.

Hope that someone advises on how to attach the bottom of the duct run to the sloped work plane, and/or that Autodesk resolves this issue with the sloped duct runs in the near future, which seem to be an issue.

Thanks a lot.

[RobDraw]

I think you may be missing part of the equation by rotating the entire run unless you did the math beforehand. Rotating the entire run so that your slope is correct between the start and end points does not account for additional length created by the bends but that isn't hard to figure out what the rotation angle should be with the additional length.

[Anonymous]

RevitMEP does not has a way to do an odd shaped and sloped duct beginning with the drawing of a line  that follows the path, and then which you can also (in addition to know the length of the line) assign the slope to the line, and then easily convert the line with just the click of a tool or a command, to a duct?

[RobDraw]

No, it is not that easy with duct but it is fairly easy to find out what the difference in elevation should be for the entire length of the run and then figure out what angle to rotate the entire run to.

[Anonymous]

I believe that what you are saying that the length that is to be used to get the lower and upper points of the ducts with the odd shape is the sum of the lengths of the lines of the legs (sides) of a triangle (for instance, assuming 90 degree legs for the sides for simplicity) rather than the length of the hypotenuse (that is, do not use the diagonal!).  Is that correct?

[RobDraw]

Yes.