Conduit Elevation Tag problem

[jalvino]

When I try to tag the Bottom of Conduit it shows up as a formula (ex. BOC: 2,175.8-2.9/2). The basement finished floor elevation is 184'-2".  I have tried setting the elevations in Project Navigator and it doesn't seem to work. This is a very large job and I would like to set up an autotag to show the elevation and conduit size but without fixing this I can't even try to set that up. Any help would be greatly appreciated.

[Keith.Brown]

This came up a couple of weeks ago. You can read the post and the solution at the link below.

http://forums.autodesk.com/t5/AutoCAD-MEP-General/MEP-2014-making-elevation-tags-for-electrical-cond...

Basically there is a units issue with the bottom of conduit calc.

[Keith.Brown]

Oops. The problem is with locationZ instead of the bottom of conduit calc.

[Tom_Eitelbach · Accepted solution]

If you are using project navigator, are you drawing your floors at 0 elevation? When I use PN I draw each floor at 0 and PN will stack the floors accordingly when they are X-Refed .
For what you are trying to do you need to make a manual property that sets your floor elevation 184'2" then make another formula property that takes the bottom of conduit calc and subtracts the elevation property. Then make one more property for your tag. This one will say BOC: and your last property.
I hope that makes some sense.

[Keith.Brown]

I am still not quite sure how you fixed the issue with the incorrect reporting of the elevation formula.  Did you follow the steps in the post that was linked?   

In regards to trying to set the elevation to 184'-2".  First you need to understand how the project navigator works.  You set up all of your levels and then you assign a drawing to a level.  When you open the drawing and start modeling everything will be referenced to the relative elevation of 0'-0" of that drawing.  Even if the drawing is located on a level that is 300'-0" in the air a conduit drawn at 10'-0" will only be at 10'-0" in its drawing.  In the project overall it will be at 310'-0".  So if you take a drawing at the first floor elevation (0'-0") and reference in the 300'-0" drawing then your conduit will be at 310'-0" in the first floor drawing but still at 10'-0" in its own level.  This is because when tagging objects in the MEP world the elevation that is needed is "usually" the elevation that the installer will be standing on when installing the product.  That being said, different contractors have different requirements.  In the process piping world i believe that the absolute elevation is what is needed most of the time regardless of the level it might be on.

If you want your conduit to be tagged at the absolute elevation of the project instead of the relative elevation of the drawing then there is no need to setup a manual property definition.  AutoCAD MEP has provisions to do this for you automatically.  Instead of creating a manual based property definition create a project based property definition and choose the Level Elevation option.  This will give you the elevation of your level in relationship to the project.  You can then add this elevation to the elevation of the conduit to get your overall absolute elevation.  You can add this to your template and not have to worry about it again.  Every new drawing that you create in the project will know its elevation and all the elevation tags will update themselves accordingly.  If you are modeling during the design phase then it is quite possible that the elevations can change.  Using this method the tags will update automatically.  Using the manual property definition method you will have to update the elevation on each and every one of the conduits in your project.

For the record there is also a method of achieving the same result using spaces on a smaller level.  i.e. what about elevation changes on a single level.  For instance, what about a server room where the level of the floor might be 2' lower to house all of the cables.  This is still the same level but the elevation has changed slightly only in a couple of rooms.  To handle this you can use spaces and have the space automatically report its elevation.  Then any conduit that passes through the space will realize that it needs to add/subtract the space elevation offset to its overall elevation.

AutoCAD MEP is quite powerful and is a fully functioning BIM application if you understand how the basics of the software work.

[jalvino]

Keith, 

Thanks for all the help. Yes, I followed the steps in the link you provided to change the units for location Z back to standard. I have been running into this problem for a few years now. I am still having trouble understanding how to set up the elevations with project navigator. My solution right now is I am saving a seperate file to create my shop drawing just moving my model down to elevation 0" to show my elevations. I am in the middle of coordination on 2 large projects and I would like to set everything up the correct way but not sure if I am going to have time to play around to get it right. I can attach a file if it helps.

[jalvino]

The problem with drawing at 0 is I am in coordination and everyone is drawing at true elevation. So when I append my files in navisworks I have to move my file everytime to run my clash detection. It is much easier to draw at the true elevation. If there is a simplier way than I would love to learn how. I am in the middle of coordination of 2 large projects. 

[Keith.Brown]

You can transform the file in navisworks ONCE and it will stay.  Then everytime you upload a new drawing it will be at the correct elevation.  You will need to make this transform in the master file.

[Keith.Brown]

p.s.  When i say upload i mean overwrite the old one.  Because the transform is stored in the master file you can supply a new file and it will also be transformed to the correct elevation.  So what you need to do for a drawing that is at 184'-2" is just draw at 0 elevation like you normally would and then in Navisworks transform the drawing by 184'-2".  This will put the 0 elevation of your drawing at 184'-2".

Moving your drawing to different elevations for shop drawings/coordination is a waste of time and should be avoided at all costs as mistakes can happen.  Navisworks has this ability built in for you.

Good Luck.

[jalvino]

It sounds great but the other Subs and the GC are not going to do that for all of my files. 

[Keith.Brown]

Well that is on them.  Drawing at an absolute elevation is silly and really has no place in an AEC environment in my opinion.

Modifying the elevation in the Navisworks .nwf file is no different than bringing in an xref in a dwg file and then elevating it to its correct elevation.  It is the same thing.  You should educate the GC and other contractors on what they are doing and how they could be doing it better.  Personally i would hate to have to calculate the elevation of an object relative to its current floor every time there was a clash.  i.e.  There is a 9'-6" ceiling in that room what elevation is your conduit at.  Well it is at 195'-4".  Obviously some calculations need to be done to figure out the relative height.

One last option that you can do is export your design as a nwc file.  Open that file up in navisworks and transform the file using the method i described above.  Then save the file as a nwd.  Then you can share the nwd file with your design at the correct elevation.

Finally in your dwg drawing you can setup two different property set definitions.  One to report the absolute height and one to report the relative height.  You can have access to those property sets in navisworks so that you can always visually see the relative/absolute height.

[Tom_Eitelbach]

I probably should not have said a manual property, but I was not at my computer. I should have said formula property even though it is not a formula just a number. Even so I see your point. This was my work around the last time.

The problem I had with using spaces, is that once the pipe is taged in one space, it keeps the same elevation information on the pipe when it leaves that space. Unless the pipe is broken or there is an offset, it keeps that information. That was my problem anyhow. The only way around that, that I can think of is to tag the hangers to get the elevation.

Good point about the project properties I will have to look into that the next time I run into the same situation.

[Keith.Brown]

Hi t.eitelbach,

The pipe should be updating as soon as it leaves the space.  It could be that the tag is not updating.  If you run the OBJRELUPDATE command it should then reflect the correct value.  In either case i have not seen this issue on my drawings.  I would also make sure that you are using a LOCATION based property set to get the information from the space.  That is the only type of property set that can be used with spaces.  Additionally once you create and attach the LOCATION based property set to the object when you then select the object there will be an extra "badge/grip" at the object.  You can drag this grip around and place it where you want.  This badge/grip is the point at which the property set determines which space it is in.  This is usefull if the object falls between two spaces.  For instance a valve inside a wall.

[Tom_Eitelbach]

Here is a drawing with two spaces and some conduit. I posted awhile back at another site and no one replied on how to fix it, What I can see in the test drawing is what I described earlier. The conduit keeps the elevation property from the space it was first tagged.

[Keith.Brown]

There is nothing wrong with the drawing that you supplied.  A single conduit can only exist in one space at a time.  You can however drag the location marker to other spaces to change its location.  Additionally when tagging a conduit, the tag will always reference connector 1 of a MEP object.  pipe, duct, conduit, tray, etc.  So tagging multiple times will always tag the same spot.  Finally when splitting a conduit it is best to delete a tag and replace it instead of trying to reanchor to an existing conduit.  In the video below I have turned on tag anchors to illustrate this point.