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Relocating Model for Linking Origin-to-Origin

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Message 1 of 6
johnal_l
1505 Views, 5 Replies

Relocating Model for Linking Origin-to-Origin

The Mechanical team received approval to start drawing before an architectural Revit model was available. The layout is essentially a big rectangle and rough dimensions were provided.

 

Now an architectural and structural model exists and there is a project base point that can be referenced.

In an ideal world (for reasons I don't fully understand), we will link in arch/struct/elec models using Positioning: Auto - Origin-to-Origin. I can get the models to line up fine if I use Auto - Project Base Point to Project Base Point, but I have had no luck if I do Origin to Origin regardless of how I adjust coordinates/PBP/SP in the mechanical model.

 

After quite a bit of reading through the forums, it appears as though there is no good way of adjusting coordinates/PBP/SP for what has been drawn so that when we link in the arch/struc/elec we can position Origin-to-origin without actually shifting the drawn elements to a new location. No amount of acquiring coordinates or moving PBP/SP actually moves the model as it relates to the (hidden) origin.

 

I feel like I am at an understanding of about 85% with this -- so my apologies if I misspeak. I guess I am just looking for confirmation on this so I don't spin my wheels.

 

Unfortunately, I cannot share the model or any screenshots for this particular job so I’ll try and be as descriptive as I can.
-------------------------------
General Mech Model Info:
Rectangular in shape with Grid Lines (A through K) and (1 through 5)
PBP Visual Location: Grids K-5
SP Visual Location: Grids K-5

PBP Shared Site Info:
N/S: 0'0"
E/W: 0'0"
Elev: 0'0"
Angle to True North: 0.00

 

Survey Point - Internal
Shared Site:
N/S: 0'0"
E/W: 0'0"
Elev: 0'0"
-------------------------------
Attempt 1:
From Mechanical Model

A)
Insert/link Arch model using Auto - Origin-to-Origin option.

 

B)
The architectural model's K-5 grid intersection appears at mechanical model's C-2 -- which is where the Mech's PBP goes when we "Move to Startup Location", aka Internal Origin:
N/S: 95' 10 173/256"
E/W: -251' 6 247/256"
Elev: 0'0"
Angle to True North: 0.00

 

C)
Unlink/Remove Arch model

 

D)
Select PBP Shared Site (still clipped) and set to the following values obtained from "Move to Startup Location":
N/S: 95' 10 173/256"
E/W: -251' 6 247/256"
Elev: 0'0"
Angle to True North: 0.00

Survey Point - Internal Remains at:
N/S: 0'0"
E/W: 0'0"
Elev: 0'0"

(Note, if I set/acquire coordinates from the ARCH model, the survey point moves to the C2 location and is 0'd out, and when I move my PBP to the SP, it gets 0'd out as well – I suppose this is expected behavior with the understanding that these are just reference points)

 

The idea with this step is that I thought I was moving my model and the PBP to the Internal Origin because it remained clipped.

 

E)
When I now link in the Arch model using Auto - Origin-to-Origin option, the arch model's K-5 location is again inserted at the mechanical model's C-2.

 

Again, with the understanding that Revit's internal origin never moves, I thought by moving my project base point (while clipped) to the coordinates obtained from "Move to Startup Location", that I would be moving my PBP and the physical model to the internal origin so that I could link in my arch model using Origin to Origin and have them be lined up -- but it does not.

-----------------------

Dirty method:

If I instead move the PBP unclipped, and then select all the drawn elements/equipment and move them over using grid line K-5 as my start point and C-2 as my destination, and THEN link in the Arch model using Auto - Origin-to-Origin, everything is lined up. However, I get all kinds of errors about duct/pipe having been modified to be in the opposite direction causing connections to become invalid.


Quick note: I just found a link to David Baldacchino's "Navigating Through the Storm Using Coordinate Systems in Revit" video.  I won't have an opportunity to watch it until over the weekend, but I've heard it's helped a lot of people understand the coordinate system in Revit. 

5 REPLIES 5
Message 2 of 6
ToanDN
in reply to: johnal_l

Why not using shared coordinates?  

Message 3 of 6
johnal_l
in reply to: ToanDN

Thanks for your prompt response.  

 

Normally my workflow starts with me linking in an architectural model with positioning Auto - Origin to Origin (depends on Project Criteria), and then I acquire coordinates from the architectural model.

In this case, the mechanical drawings were started well before we had an architectural model to acquire coordinates from and now we're trying to link in the arch model.

 

If I try and bring in the architectural model using "Shared Coordinates" positioning I get the Differing Coordinate Systems window stating "The host model and the link do not share the same coordinate system. Default center-to-center positioning will be used."

 

I'm sure I'm misunderstanding what you're telling me to do or I'm missing something obvious.

Message 4 of 6
ToanDN
in reply to: johnal_l

Here is what I do and it always works:

- a site model with a proper shared coordinates established
- link it in the building model (origin to origin, center to center, doesn't matter)
- relocate it to align with the building model
- acquire shared coordinates
Message 5 of 6
PaulineP54QC
in reply to: ToanDN

Hello,

We are working on a BIM 360 revit 2020 linked arch and mech model. We noticed the "survey" and "origin" or "center point" symbol shown on the drawing. It was too annoy since you cannot double click w/middle button to zoom all, the model will disappear. I learn through the forums how to turn them all off, but after we did the architect model and the mechanical are not in the same coordinate. I am not sure if your step by step will resolve it, anyway can you expand a little bit more? I am not a Revit guru. Thanks! 

Message 6 of 6
fabiosato
in reply to: PaulineP54QC

Hello,

 

It seems that the 0,0,0 of the survey point is too far away, one way to avoid this problem, is to select the survey point, unclip it and move it near to your model, you will note that the coordinates in the survey point change, but the coordinate reference stays the same.

Fábio Sato
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