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Piping & Vertical Justification

9 REPLIES 9
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Message 1 of 10
jcook
2976 Views, 9 Replies

Piping & Vertical Justification

Question is mainly directed toward Kyle or someone else from Autodesk....First a little drawing and then my question so you can follow.

Draw three different pipes in a line in plan view (-2' from level) with one pipe drawn with vertical justification top, next one middle and last one bottom. Cut a section on the pipes and go to section. Draw a detail line from level down 2' and over past the pipes (turn on fine detail level) and click on each pipe to show elevation of end points.

What is the reasoning for the offset when the pipe was drawn not matching up with the end elevation of the end point marks when using bottom and top justification? Why does the (pick bottom justified pipe) end marks show up at the bottom of the pipe but the elevation information still refer to the middle of the pipe and if you alter that elevation it reverts back to the middle justification? I was expecting the elevation information and the manual adjust of the pipe by changing the end elevation marks to match up with whichever justification was used.

thanks

John
9 REPLIES 9
Message 2 of 10
jason.martin
in reply to: jcook

What is the reasoning for the offset when the pipe was drawn not matching up with the end elevation of the end point marks when using bottom and top justification?

The assumption here is that you had a "hard ceiling" or "hard deck" (to take some terms from a completely unrelated flight analogy) that you were trying to draw around. You set the justification to "top" and the offset to 10' and draw. When you change sizes, the "top" remains at 10'. When I actually try this in 2008, I seem to be getting some results that I wouldn't expect, so some of my explanations of what the "idea" was may not make sense with what is actually happening.

Why does the (pick bottom justified pipe) end marks show up at the bottom of the pipe but the elevation information still refer to the middle of the pipe and if you alter that elevation it reverts back to the middle justification?

OK, hold 2 questions confuses me. Let me try to answer them separately...

Why do the bottom justified pipe end marks show up at the bottom of the pipe but the elevation information still refer to the middle of the pipe?

So, I'm going to start this answer with a question (actually I started it with a statement, since I said I was starting with a question). Do you want the pipe to move when you change it's justification? If you have a pipe drawn right justified so that it is tight to the wall, but you don't want to use eccentric reducers, so you change it to center, do you want the location of the pipe to actually change? Our assumption was that you don't, you just want to adjust the justification. That's why we always report the "offset" of the pipe as the "center" of the pipe no matter where we draw the "justification controls". If we only track the "justification" point and you change that then we would need to move the pipe from its current location to align with its new justification point. If we track the center points and you change the justification then the justification can change without moving (and possibly disconnecting) the pipe.

if you alter that elevation it reverts back to the middle justification?
I'm actually not seeing that behavior, but I am seeing a defect in the elevation that the controls are reporting after the pipe offset is changed. I'm seeing the pipe still be justified as it was (justification is set correctly for the pipe, and the controls are correctly drawn at the top or bottom), but the control are reporting the "offset" rather than the control location (offset +/- 1/2 Pipe Diameter).

I was expecting the elevation information and the manual adjust of the pipe by changing the end elevation marks to match up with whichever justification was used.
I certainly understand this expectation, but one thing that you need to be aware of is that in many cases the onscreen controls actually don't report the "correct" number even when they are middle - center justified. If I have a pipe that is sloping and it connects to another sloping pipe through a 90º elbow. Let's say that the 1st pipe has a lowest middle center elevation of -3'0". If you select the other pipe you'll see that it reports its highest middle center elevation as -3'0" as well. Neither of these pipes actually have a middle center at -3'0" (and the properties dialog will confirm this), but the controls, in this case report the elevation of the "imaginary intersection" of the pipes, so that you have a chance at some day getting them to match up when you want to try an connect things. Otherwise you would have to try to take into account the amount of elevation change that the elbow between the two pipes makes, because it is also installed at a slope (kind of a "double" slope). We could never figure this out easily when we were trying to make connections between sloping pipes, so we decided to let the computer figure it out for us, and to simplify the onscreen interaction by reporting this "incorrect" (but much more calculable) number, rather than being strictly correct (but impossible to use).
Message 3 of 10
jcook
in reply to: jcook

Thanks for the response. Very helpful to understand the intention of how it was intended to work.

The defect in the elevation information reported is the same as what I am seeing (didn't convey information correctly).

Comments about the elevation that is reported from a plumbing perspective: I can't speak for all, but most of the time when we deal with laying in plumbing or drainage pipes and steam/condensate lines could be thrown in also, we deal with the bottom inside point in the pipe to guide our pipe design. Top of the pipe is really only important as far as having enough cover (underground pipe) over the pipe. I understand that using the middle elevation information is relatively the same as the bottom as far as slope is concerned. The problem with this is that when plumbing drawings are produced we typical provide to the contractors invert elevations at various location along the plumbing layout. The invert elevations are the bottom inside point of the pipe. It is easy enough to adjust the elevation information revit provides at the center of the pipe and adjust it down when inverts are called out, but if your not aware that the information is always center of the pipe you can create confusion in the drawings between disciplines. Adjusting all those invert elevations down in a leader/note by hand is quite frankly a PITA. With all the things revit can do this seems like a good function that could be built in for the plumbing (something to provide invert elevation, a special leader for invert elevation like the spot elevation maybe).

Anyway, my 2 cents,,,,thanks again, very helpful

john
Message 4 of 10
jason.martin
in reply to: jcook

Pipes have a parameter called "invert elevation" that "should" be the bottom, inside point of the pipe that you can tag. We take the lowest point of the pipe then subtract out 1/2 of the ID of the pipe to get this value.

There is a problem with this value today, in that it is always reported in "project elevations" (i.e. doesn't respect the level on which the pipe is placed).

hth

jason
Message 5 of 10
jason.martin
in reply to: jcook

One more thing that I realized since I posted the last message. What I indicated was a defect may, actually, not be a defect (but I'm having some trouble trying to remember how it was designed).

Based on what I said earlier, if we want you to ever have a chance at getting some pipes connected we need to tell you where the "connection points" are which are the centers, and allow you a chance to line these up.

The controls, even though they are drawn at the top of the pipe, will always report (and modify) the connection point of the pipe.

I understand that these controls are confusing and they have been the issue of a number of internal discussions as we really want to remove them, as well as remove the fact that the elements "remember" how they were justified, as if you rotate and modify the segment enough these justifications can be quite useless. There remains one icky sticking point that we haven't been able to figure out how to solve without these controls yet. I'll try to take a look at this again and see if we can find a way to solve this without all of the confusion.

jason
Message 6 of 10
jcook
in reply to: jcook

Yes, we have used the pipe parameter for invert elevation and it works well. However, I probably wasn't clear enough on what I meant about the spot elevation. Lets use a single run of sloped pipe for an example. The pipe parameter for invert elevation will let you tag the pipe, but it only provides tag information at the invert elevation at the low end of the pipe. There are numerous occasions where the upper end of the pipe and sometimes in the middle of the pipe that we need to provide elevation information. The tag as it exist now can't do that. What we typically do is split the pipe to get invert elevations if we need it in the middle. What I was meaning was that determining the elevation along the pipe would seem to be an easy enough calculation and implementation in Revit.

Thanks again

John
Message 7 of 10
jason.martin
in reply to: jcook

Hi John -

Just want to clarify the requirement before logging a request...

You want to be able to indicate the elevation of the bottom of the inner
diameter of the pipe at any point along the pipe.

Are there requirements to indicate the outside elevations as well (top and /
or bottom) at any point along the pipe so that "clearances" can be verified?
Would having insulation on the pipe change this value?

(I assume there is no need to have the top inside diameter elevation (I
can't imagine what this would be useful for, but as long as I'm asking stuff
;-)).

tia!

jason
wrote in message news:5772827@discussion.autodesk.com...
Yes, we have used the pipe parameter for invert elevation and it works well.
However, I probably wasn't clear enough on what I meant about the spot
elevation. Lets use a single run of sloped pipe for an example. The pipe
parameter for invert elevation will let you tag the pipe, but it only
provides tag information at the invert elevation at the low end of the pipe.
There are numerous occasions where the upper end of the pipe and sometimes
in the middle of the pipe that we need to provide elevation information.
The tag as it exist now can't do that. What we typically do is split the
pipe to get invert elevations if we need it in the middle. What I was
meaning was that determining the elevation along the pipe would seem to be
an easy enough calculation and implementation in Revit.

Thanks again

John
Message 8 of 10
jcook
in reply to: jcook

Jason,

Yes, bottom (low point) inside of the pipe and anywhere along the length of pipe.

In my particular field, the top and bottom outside of the pipe (with or without insulation) is not a critical elevation. We do check it when we have crossings that are really close. I could see areas where that information would be nice to have or even necessary depending on the design.

My 2 cents, if you are going to create a tag / spot elevation for the bottom inside of the piping, why not put some options or check boxes where you could pick the elevation information that was going to be displayed. That way plumbing inverts are covered and outside pipe inverts on overhead piping are covered. Something like Pipe invert as the heading with "sub boxes" that you could check on/off like inside bottom, outside top, outside bottom, outside top w/insulation, outside bottom w/ insulation.

Anyway I maybe getting a little greeding (I would be happy with just the bottom inside elevation along the pipe).

thanks

John
Message 9 of 10
Vipcanabis
in reply to: jcook

Dear gentleman,

 

I have issued with the vertical justification (VJ) that I can't change to Bottom or Top instead of Middle. 

 

Now matter how I find.

 

Searching through the internet and many forum said that It's normal when Revit display the VJ in middle.

 

The problem is a few first duct I draw is just fine. Until I made a section and connect 2 difference elevation duct (by a automatically offset).

 

From that, VJ become middle instead of bottom no matter how I change.

 

Is there something that I missed ? or I do wrong ? Could someone can help me to find out.

 

*Deeply sorry for my bad english.

Vertical Justification_LI.jpg

Message 10 of 10
ivanm
in reply to: jcook

12 years later and I assume this idea didn't get implemented. Sad because being able to tag and draw with real inverts would make UG projects whole lot simpler. Now I'm creating tons of reference planes just to model per Civil and then another ton of planes to be able to tag.

As users above are mentioning plumbers don't care about pipe centers.  

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