Active View can Matter When Linking Using Positioning Auto - Center to Center

If you link a model via Positioning: Auto - Center to Center in a plan view its zero elevation will align with the host model's zero elevation.

Do that in an elevation or section view however and the linked model may not rest at the correct Zero elevation. The discrepancy man be very subtle or quite obvious. It will depend on the adjusted extents of the view that is active.

The trigger appears to be the elevation or section view being cropped very shallow (only one level visible) prior to linking the model (tested as far back as Revit 2015). If all the levels are visible in the view it seems to be more reliable.

Far safer me thinks to just link via a plan view, something to watch out for. 

Revit 2016 R2 - Positioning by Auto - Project Base Point to Project Base Point

This is an interesting development for reconciling the misalignment of models. This gives us the option of linking a RVT model according to the location of its Project Base Point (PBP) and aligning it with our own.

Let's imagine a scenario where our structural engineer decides to mock-up a preliminary model but does so without the benefit of having the architectural model linked in yet. This new feature allows the engineer to either move the PBP un-clipped (see warning below) to an agreed upon grid intersection or to start by placing their grids at the default PBP location in their model.

All I have to do to get their model to align with my model properly now is make sure I move my PBP un-clipped (again see warning below) to our equivalent grid location or be grateful I was lucky to have guessed that we'd start our grids at the same location to start with. If I didn't guess correctly then moving it un-clipped puts it in the correct location and the link lines up nicely.

Being able to move the PBP un-clipped is helpful for Revit to Revit alignment. It DOES NOT address exporting to DWG however (nor appending to Navisworks). If each model is exported using Coordinate System Basis: Project Internal they will not line up with one another because the model's file origin is not altered. If each trade is careful to start modeling the agreed upon grid intersection at their templates's default PBP location (not moved at all) then they'll line up when their exported files are opened in AutoCAD or Navisworks.

I'm not sure we can rely on that if we can't count on them waiting for our model to use as a linked reference first? Still it is an interesting development. Hopefully it doesn't just contribute to the existing confusion regarding linked RVT file positioning.

My recommendations?

• Make sure all trades agree to begin their work referencing their own PBP with the same understanding. For example, agree in advance that the bottom left grid intersection shall occur at the PBP location (like shown in my images). This will ensure that exported data will have the same file origin.
• Don't move the PBP un-clipped to reconcile the PBP location IF you want to be able to export using Project Internal.
• Only move the PBP un-clipped if you will rely on Shared Coordinates to deal with external model alignment in other applications.

Survey Point - Post 4 - Acquiring Coordinates and View Orientation

The bias of the last three posts has been on creating a Master Site file and linking building models to site. That's moving buildings on a fixed site versus moving the site under fixed buildings. The earth doesn't go anywhere, we put buildings on it, so to speak. That bias feels right to me, the ways things really work.

These are links to the three preceding posts.

Survey Point

Survey Point - Post 2

Survey Point - Post 3 - Five Minutes with Shared Coordinates

If you choose to take the reverse approach, link the site to a building, you have to adjust the survey information to align with the building; since its harder to move the model elements around than the survey file. In this example, I've started in a Floor Plan view assigned to Project North.

At this point is doesn't look much different than images early on in the other posts. The building is oriented conveniently for putting in on sheets. I need to move and rotate the survey DWG into a better orientation. I'm using the same preferences I had in the previous posts.

Now I just need to shift the survey down since the contours are at their actual elevations and the building model is at an arbitrary ground floor elevation of zero.

I used the same 22 feet for the ideal ground floor elevation I chose in the other post.

Now I'm ready to use Acquire Coordinates. I opened up both the floor plan and site plan views so I can see the change occur. I used Acquire Coordinates in the floor plan: Level 1 (that's significant...in a moment).

Since there are few possible combinations of actions, let's imagine that I used Acquire Coordinates a little differently. In this case I Acquired Coordinates in the floor plan view: Site and I wasn't observant enough to notice that the view is assigned to Project North which ordinarily wouldn't make sense to do, to me at least. It's easy enough to overlook because at this point the building orientation is technically the same as it is in other views assigned to Project North.

After I Acquired Coordinates I noticed the view didn't change so I realize it needs to be assigned to True North. I do that and the model rotates to show the orientation based on the survey's coordinate system, as I expected initially.

Now a little time passes (we're pretending). I find it necessary to use Reload to update the linked survey file, maybe I cleaned up some of the layers to make it a little lighter in our model. When I click Reload this happens. The survey spins out of alignment.

The cause is subtle and simple: it is IMPORTANT to respect the Orientation parameter setting used, in the view that's used, when Acquire Coordinates is used. If you change to the opposite setting and then Reload the link the orientation of the link will change undesirably; regardless of the view you happen to be using during the reload process.

To restate the cause and effect, I used Acquire Coordinates in the Site view while it was assigned to an unnatural orientation setting of Project North. I then changed it to use the more logical True North but AFTER I already used Acquire Coordinates. This means I have to remember to change it back (to Project North) EVERY time before using Reload on the Linked survey file... Or I fix it, which would require resetting the coordinates so I could Acquire Coordinate again with the better settings in place.

I believe this is another good reason to use a separate Master Site project file. The survey is linked and moved into position but it isn't rotated to reflect True North because UP is North already. The quirk I've described only affects the links rotation and there is no need to rotate it in the Master Site strategy.

Survey Point - Post 2

Yesterday I ended the post with a list of steps that I'd take to create a relationship between my building project file(s) and the Master Site file. I started another pair of projects that I'm calling Tiny House A and B (inspired by Sean's Tiny House project). I can start a project with or without site context. Revit's bias is making the project easy to document, forget about True North initially. It is trivial to resolve that in the Master Site file once it is ready, regardless if it is created before or after the tiny house models are started.

Here's how far I took the design of Tiny House A before I decided to work out its location on site.

I closed Tiny House A's project file. I opened up my Master Site file and linked Tiny House A using positioning: Auto - Origin to Origin. The choice for positioning at this stage really doesn't matter since I'm going to move the file to another part of the site anyway; have to pick something so I just let the default option reign. In the following image you can see Tiny House A is sitting at/near the Master Site's origin, marked by the Project Base Point icon.

Now it's time to move Tiny House A into position. I moved it and then aligned it with the East boundary. Then I was careful to put it at 8'-0" from that boundary. I then made sure the closest corner (wall) of the house to the North boundary was also at 8'-0". Being fussy about this isn't particularly important, I'm just being fussy.

Now I want to make sure the house is at an appropriate ground floor elevation. I created a section view so I could see the site's contours and the floor of the house. I can see here that the house is buried under a fair bit of the site.

I decided that raising the house to 22'-0" feels good. I used the Move tool, and typed 22 into the temporary listening dimension that appeared.

I think I'm ready to deal with Tiny House B now. It's really just another project file saved with a new name. I was too lazy to make another design. If this was a real project I wouldn't be able to get away with that. I decided that this house has to be no closer than 8'-0" to the North boundary but I've also made the North end of the house parallel to the boundary.

I learned while reading the development's covenant and zoning requirements that these houses can't be closer than 15'-0 to one another. I decided to put Tiny House B 18'-0" from A. I heard that A's owner is a drummer so those extra three feet might help keep B's sanity. I also decided that the ground floor elevation for B should be 20'-0", a little bit lower than A.

Now that I'm satisfied with the positions of Tiny House A and B I'm ready to use Publish Coordinates. This tool will PUSH the site orientation information to each house's project file. Revit will use this information to shift the house's Shared Coordinate system to align with the Shared Coordinate system of Master Site. In yesterday's post, the Master Site was manipulated to be in alignment with a linked DWG file's WCS (the World Coordinate System in AutoCAD to be precise) through the use of the Acquire Coordinates tool.

When you successfully select a linked file to Publish Coordinates the Location Weather and Site dialog appears. This give us an opportunity to provide a meaningful name for the location we're creating for that model. I clicked Rename... and typed Tiny House A Location 1.

It's significant to appreciate that I could now create a copy of Tiny House A in Master Site and place this copy in another location. I could then use Publish Coordinates on this copy which would allow me to use Duplicate... and use another name like Tiny House A Location 2. In the Tiny House A project file I can now choose between these two named locations and make one of them current. Revit will reorient everything to show the building correctly for this location, all without really changing anything  in the model. It's pretty clever and powerful; actually doing it is something I'll save for another post.

I used Publish Coordinates again but on Tiny House B and used the name Tiny House B Location 1 when the dialog appeared. I'm ready to return to work on my Tiny House A design. I clicked Save so I can close the Master Site project. The following dialog appears twice, once for Tiny House A and the second time for B. This is confirming that I want to commit the location and shared coordinate changes I made while using Publish Coordinates. I clicked Save each time (2x), the top option in the list.

It is necessary to make sure others are not working on the Tiny House A or B now. The Save will fail if someone is working on them. Just ask them to close the project for a minute. When worksharing is involved the same is true but it is a bit more forgiving. Either way, if an error message appears you need to ask others to stop working on these files briefly; they need to Save and close them. Once my Save is completed they can get back to work.

When I open Tiny House A I find that the Site plan is oriented to True North. I changed the Orientation parameter to True North earlier (noted in the image at the beginning). All plan views in the stock templates are assigned to Project North, including the Site view. Changing it meant that I'd see the results of using Publish Coordinates immediately, or at least as soon as I bother to open the Site view. The reality of this is that the project is NOT altered materially, no physical change to any geometry, it is just oriented correctly based on my actions in Master Site. This trivializes the task of re-positioning a building on site, if that becomes necessary.

Taking things a little further, each Level type has a Type Parameter called Elevation Base. It can be assigned to either Project Base Point or Survey Point. When I change this to Survey Point I find that the levels are reporting elevation values based on how much I raised Tiny House A in the Master Site file.

Now I've decided I want to be able to see Tiny House B here too, for context, but while working on Tiny House A. I linked Tiny House B into Tiny House A using positioning: Auto - By Shared Coordinates. This is possible because I used Publish Coordinates, from within Master Site, on both Tiny House A and B. Their shared understanding of their position in Master Site makes it possible to link either file into the other using Auto - By Shared Coordinates and they land in the correct spot relative to each other.

I can also link Master Site into either Tiny House A or B and use Auto - By Shared Coordinates too. They all understand their relationship to each other because of Publish Coordinates and the work I did in Master Site to put them into the proper context with each other. Here is Tiny House A, with Tiny House B linked in. I also created a Toposurface and Building Pads for each house in the Master Site file, then I returned to Tiny House A so I could link Master Site in using Auto - By Shared Coordinates as well.

A Few Notes

• Master Site is in CHARGE of positioning
• Only move models in Master Site
• Do not move linked models when viewed in other related project files
• Acquire Coordinates created the relationship between Survey and Master Site
• Publish Coordinates created the relationship between Master Site and Tiny House A and B
• Respect this order and it is easy to maintain
• It is technically possible to manipulate the relationship in either direction, DON'T.
• You must Resist the temptation!

Multi-Discipline Comments:

• Trades link the Tiny House A and B models into their projects using Auto - Origin to Origin, nothing else.
• Do NOT start work without a preliminary model of the Tiny House. If you do, be prepared to move your work into alignment manually.
• It is only necessary to use Acquire Coordinates on Tiny House A or B (whichever house you are designing for in your project file)
• It is only necessary to use Acquire Coordinates IF there IS an expectation that your data must align in 3rd party software like Navisworks
• The Tiny House projects will link your models using Auto - Origin to Origin too