Thursday, 19 December 2013

Revit origin

Recently I was asked how can you tell if someone has been playing around with the project base point and survey point.

If you have a good template your survey point and project base point resides on the revit origin. It's good to know that you can adjust the survey point and the project base point but the Revit origin is fixed.

The first indication that the survey point and the project base point have been moved is of course that they are not at the same position any more. The second one is: select the project basepoint. If it has values other that all zeroes it has been moved. 

To check files you may use this old trick to find certain points. Draw a tiny drawing in Autocad. I like an X with a circle on the Autocad origin. Save the file and link the drawing in Revit with these settings.
Auto origin to origin.
The image below shows two projects side by side:
In project two I have moved (the left one) the survey point and the project base point unclipped. Next I have imported an autocad drawing origin to origin. Notice where it shows up. So if the autocad drawing does not land on top of the project basepoint or surveypoint than they have been moved. 

In the project shown on the right I have moved the survey point and project base point in a clipped state. When you do this you see that if I link in the same dwg as before it lands on top of the project base point. 
Moving a clipped project base point is the same as using the Relocate Project tool. See Relocating a Project.
  • Project coordinates do not change for the model elements.
  • Shared coordinates change for the model elements.
The helpfile explains it quiet well. Since I am more a visual person I am going to take the files to Navisworks.

Project 1 (image below) The survey point and project base point are both on top of the revit origin. The dwg file has also been loaded into this naviswork file. Since nothing has been moved everything is where you expect it to be.
Project 2 (image below) The project basepoint and survey point have been moved. Notice how navisworks places the survey point on top of the autocad file.
Project 3 (image below) The project basepoint has been moved. It seems to have the same result as project 2 but, the big advantage is that when revit files do not share coordinates you can always link them origin to origin. 
Another advantage is that if those revit files are not linked you can enter the coordinates of the project base point in Navisworks and everything ends up where they are supposed to be. See image below. 
(Or you can enter the project basepoint coordinates form one revit file into the other one. That is what the publish and reconcile command does as well)

Personally I prefer the setup of project 3 it facilitates automatic feature and fix it yourself if things go pear shaped.

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