Friday, 8 August 2014

location marker

In my previous blog I wrote about trying to get project to link in properly when shared coordinates have been set and they do not match.

Revit has a very nice tool to report coordinates of a point. But you first need to have something there. I was looking for some sort of autocad like functionality of putting something you can snap to at exactly the right coordinates. Most likey it will be easy to do if you make use of the api and some c##. I am not so good with code so I thought let see if I can create a family who can do what I need.

I created this family called location marker. This family is meant to be placed at the project base point. If the values you need to put in are not to big then you could also place it at the survey point. 
The trick to this family was to be able to insert positive or negative values.
Dima Chiriacov blog about formula's helped me out. In order to position the snap point I have to be able to insert negative values. But Revit length parameters won't let you use negative values. But with Dima's formula's I can use negative values.

First a parameter looks if x > 0 mm then the next parameter  if(x_is_positive, 2, 0) gives me a value of 2 or 0
The same for the y value except instead of 2 and 0 it gives me 1 and 0
Next I add the results of the of the two above and they control which snap point becomes visible.
The next four images show screenshots of different xy values and it's corresponding marker. (take a look at the right in the property window)

With this family I can put a mark anywhere in my project. This can help me out when shared projects coordinates have not been setup properly and models have not been modelled relative to the revit origin.

You should be able to download the family from here:
Location marker

Thursday, 7 August 2014

Linking projects with different shared coordinates

Differing coordinate systems.For myself I had set out to see what triggers this screen.

It's been my experience that as soon as two files have different rotation values in the project basepoint you will get the warning of different Coordinate sytems. Not True! As soon as you change any value in the project base point it goes wrong. But why does it sometimes go right?

Start a new file change the project basepoint and save the file under a name, let's call it Project A. 
Next you change the project-base-point again save that file under a another name, Project B. 
If you link Project B into project A by shared coordinates it will place project B exactly where it should land.

In fact I have been using a copy of the same file and changing any value of the project basepoint, or survey point, unclipping it, moving it and so on and I do not get this screen when I link by shared coordinates. And more surprisingly it ends up where it should.

I have tested this both in Revit 2014 and 2015. No difference I'll try to show this now in screenshots
Project A: just a floor no change to either survey or Project base point
Project A saved as Project B, but I changed the project base point N/S E/W values.

Project A saved as Project C, but I changed the project base point N/S E/W values and rotation.
Next I link Project B into Project A by shared coordinates and it lands exactly where it should. Next I link Project C into Project A by shared coordinates and it lands exactly where it should.
Now I will create a new project and setup the project base point exactly like project B but I will model a floor that should end up below Project B. 
When you link Project D into Project B by shared coordinates you will get this. 
The irony is that in the preview it does it right but once you click on the button it moves to the wrong position.
(publishing the shared coordinates from B to D fixes this problem. If you then Save Project D as Project E and you try to link Project E into project B by shared coordinates it will end up where it should, ofcourse)

Before I never had this problem because I always setup the project base point manually and I link the revit files origin to origin.

My conclusion is that something else controls the ability to use shared coordinates and that the values of the project base point or the survey point do not matter.

You would almost suggest you create one simple file at the start of the project and share this file to all companies who are going to work on the project. From a revit point of view that might work but from an organization point of view it's quiet unlikely that that is going to work. What will work is if you all model relative to the revit origin and you link your files origin to origin! Once the files are in you can use the publish and acquire coordinates function.

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