Saturday, April 04, 2015

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


Gregg said...

2 great posts Steve. I'm still re reading these to make sure I fully understand the process. I have one initial question. When you move Tiny House A to its new location near the boundary, how are you doing that? Are you just doing a window select around the house and doing a mv?

In the past when I have tried performing a similar task, some elements of the building were "left behind" and since then I have been a bit gun shy in trying it again.

Steve said...

It sounds like you missed the part about both Tiny House A and B being linked files and moving them in the Master Site. It would quite a trick to only move some of the house in that context.

Unknown said...

Well done, Steve! Really enjoyed these two posts...You are creating a third-party model (master site) which may not be even shared with consultants, but it is present to organize other models' locations and relationships. Everything being controlled in the master site which is already matched with the survey file. Nicely done!

FMZ said...

Can you explain more how to link a Revit MEP or Structural file in project collaborative case. If the Architect move the building, how do you proceed ?


Matt Ivers said...

Two questions.
1) When acquiring coordinates from the Civil file that has coordinates originating further than the 20 mile radius, will it acquire and establish the correct relationship between the origin and the site?

2) In using this method, does the entire team need to use shared coordinates when exporting to Navisworks in the settings or would it just be the arch?

Steve said...


1) When acquiring coordinates from the Civil file that has coordinates originating further than the 20 mile radius, will it acquire and establish the correct relationship between the origin and the site?

Maybe - In the past when the coordinates were extremely large I found the Acquire Coordinates tool to be a little unreliable. When I checked the resulting coordinates in the file against the same location in the DWG source file they were different. In the most recent releases however I haven't found this to be true. I don't know if they have fixed something or not but when I've attempted to replicate the issue I have not been able to.

2) In using this method, does the entire team need to use shared coordinates when exporting to Navisworks in the settings or would it just be the arch?

Yes - Anybody that expects their model to be able to align with other models in Navisworks will have to specify Shared Coordinates if they export to a compatible format. If the Navisworks user just Appends a RVT model directly they can specify Shared Coordinates themselves, assuming they've been established at all.

Unknown said...

2 Great Posts Steve. Helped a lot Understanding and resolving the coordinates issues. Keep up the Good work Steve.

Alex Brunette said...

Thanks for the break-down Steve!
In the multi-discipline comments you state that "It is only necessary to use Acquire Coordinates IF there IS an expectation that your data must align in 3rd party software like Navisworks" This makes sense to me in that, if you initially linked in the architect's model origin-to-origin, your model will be positioned correctly with respect to the project regardless of any real world coordinates. It sounds then like, as a sub-discipline, if I link origin to origin and acquire coordinates I should be safe for both revit and navisworks coordination. I'm curious about any actions by the architect after this point that would make my project out of alignment. What happens if they move their buildings or somehow change the shared coordinate system? Can you speak to this at all?

Steve said...

Alex - Look for the follow up post tonight. The short answer is that it gets more complicated than my brief summary implies when the building gets moved on site after all the models have been shared with each other.

My follow up post describes how to cope with that a little differently assuming trades belong to separate firms. A single firm can cope a little better and I've described that at the end of the new post.

It should go live at 8 PM tonight...assuming I get it finished by then :)