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Author: Sash Kazeminejad Revit
If there is one thing that all of us Revit users can admit to, it would be the fact that at some point in our Revit career we forgot to coordinate our Survey, Project, and Origin points with other linked models. Perhaps we were really unaware of each points function, until it was too late.
 
I am admittedly excited about a new option for linking our Revit models, and it has to do with linking them by their Project Base Point. This new feature is available in Revit 2016 R2, and to me, it is a game changer for coordinating Revit models.
 
We frequently receive tech support cases in which the end user has received coordination models and upon linking them, none of them line up. Typically, they have exhausted each of the linking options without any success, which is where we come in. After a little history on how the project was coordinated to start with, we usually come to the same conclusion: nothing was coordinated when the project commenced. The way around the linking issue involves using Shared Coordinates, which is a little bit of work to set up and coordinate, but it is such an awesome and powerful feature, and it also keeps you honest.
 
When you take your first look at the coordinate points in Revit, it is easy to conclude that there are two coordinate system points in the software and this is because if you go to Visibility/Graphics to the Site category, you can turn on the Project Base Point and the Survey Point. The result is that you see a Triangle (The Survey Point) and a Circle (Project Base point).  Most people believe that the Origin Point in Revit is the circular (Project Base) point, but that is actually not the case. In Revit, there are three points – Survey Point, Project Base Point and an invisible point called the Origin Point. When linking Revit models Origin to Origin, Revit will align models based on the invisible point (Origin Point) and not the Project Base Point (Circular Point). What do people typically do then? Most people unclip the Project Base Point and move it to match the location of the other Revit models. After moving the Project Base Point, they attempt to re-link them Origin to Origin, only to discover that it did not work.
 
Well, the good news is that now you can move your Project Base Points to match the entire project teams Project Base Points and then link the models via the Project Base Point option. This feature will save you the time it takes to set up and coordinate a Shared Coordinate System.
 
Be on the lookout for a future video blog post that will dive a little deeper into the Revit Coordinate System.
 
In this example, we are comparing both a Structural Model and Architectural Model of the same project. Looking at the Survey Point and Project Base Point data, both models appear to be coordinated in terms of coordinate system data, which is a good thing!
 
 

 

With both the Project Base Point and Survey Point in the same coordinate system, we will attempt to link the Structural model into the Architectural model via the Origin to Origin positioning.
 
 

 

Upon linking the Structural Model into the Architectural Model via Origin to Origin positioning, we quickly realize that the models do not align. This is because the circular point is actually the Project Base Point and NOT the Origin Point. The Origin Point is actually invisible and this is what can get people in trouble when the coordinate system is not coordinated at the beginning of a project.
 
 

 

To find the true Origin Point in a Revit model, simply Unclip the Project Base Point, then right-click and select “Move to Startup Location.” By doing this, IF the Project Base Point was unclipped and moved away from the Origin Point to start with, then the Project Base Point will move back to the true Origin Point. If the Project Base Point does NOT move, then the Project Base Point and Origin Point are in alignment with each other, which means that it was not unclipped and moved away from the Origin Point to start with.
 
 

 

In our case, after selecting the “Move to Startup Location” option, we discovered that the Project Base Point was unclipped at one point in time from the Origin Point (red arrow) and moved to a gridline intersection (green arrow) to match the Structural consultants file. This explains why the Origin to Origin feature will not work to align these particular models. If this happens, unclipping the Project Base Point and moving it so that the entire project teams coordinate system matches is a wise idea. This way all disciplines Spot Elevations, Spot Coordinates, Levels, etc. will match up. The only downside is that linking Origin to Origin will NOT work, unless the Architect physically moves the entire model to the Origin Point, which becomes an impossible task at the design continues to progress.
 
 

 

If your Project Base Points align, you are not using Shared Coordinates, and linking Origin to Origin does not work out, then try linking your models by “Auto-Project Base Point to Project Base point.”
 
 

 

After failing to link our Structural model Origin to Origin, we linked it in using the “Auto-Project Base Point to Project Base point” feature, and as you can see, both projects align very nicely. In this case, we opted out of using Shared Coordinates.”
 
 

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   Sash Kazeminejad
Sash Kazeminejad
AEC Senior Application Specialist

Sash is a registered Architect and LEED Accredited Professional who holds a Master of Architecture from Montana State University. Sash’s experience includes project management, BIM management, and design for architectural firms in California, Montana, and Oregon. In addition to being a Bluebeam Certified Instructor, Sash is an Autodesk Certified Instructor who provides Revit Architecture training and solutions for AECO firms. Find Sash on Twitter.