Project North Angle

[frankholidayjunior]

What parameter will provide the Project North Angle?

The closest I could find was something about making an origin(0,0,0) and getting it's angle.  It was an autodesk help site that you needed to understand it's implication of what the angle was. It could be the angle from project north to true north?

[jeremytammik · Accepted solution]

• Unrotate North
• Rotate True North
• DevCon, Sun with True North and RVT without Revit

[Anonymous]

Hi @jeremytammik ,

I've been reading through a lot of these posts regarding Project Location, specifically in regards to Project North and True North. These are some of the posts I've reviewed:

https://thebuildingcoder.typepad.com/blog/2012/03/rotate-true-north.html

https://thebuildingcoder.typepad.com/blog/2009/10/unrotate-north.html

https://knowledge.autodesk.com/support/revit/learn-explore/caas/CloudHelp/cloudhelp/2014/ENU/Revit/f...

https://thebuildingcoder.typepad.com/blog/2010/01/project-location.html

I have a concrete column and I am trying to use the API to determine the location and rotation of the column. As of now, the most accurate way I have been able to do this is to use the Element Location (as a LocationPoint) to get the rotation value. However, the value that is being provided is not rotated with respect to Project North. However, the coordinates that are being provided within the Point ARE in the correct location. I don't understand how this is possible, but regardless I am trying to determine the correct rotation angle of the object. Using your previous posts, I am able to use the ActiveProjectLocation to get a ProjectPosition object which gives me an angle of -49.06 degrees. This is the angle between the Y axis in my model, and true north. While my project north is actually 180 degrees. So, just to be clear, my True North is 139.06 degrees, and my Project North is 180 degrees (in reference to the X axis). When I get the angle of the columns, each one is 90 degrees short of the correct angle. So what I really need is a way to determine the project north direction in reference to the X or Y axis. Or, if I can determine the project north location in reference to true north, that would work as well. However, when I use your parameter method (OST_ProjectBasePoint>get_Parameter(BASEPOINT_ANGLETON_PARAM)) I am getting the same value as the Project Position angle, only non-negative (49.06... which is also very concerning).

Any thoughts?

[jeremy_tammik]

Sorry, rather long and convoluted, I feel like Winnie the Pooh, a bear of little brain.

Are you saying you can get the proper point but not the rotation?

Can't you just add the project north rotation to the family instance rotation?

P.S. I like it so much, I looked it up:

When you are a Bear of Very Little Brain, and you Think of Things, you find sometimes that a Thing which seemed very Thingish inside you is quite different when it gets out into the open and has other people looking at it.

[Anonymous]

@jeremy_tammik 

Turns out I am the one who should apologize. Not sure which character I am, Piglet maybe? Possibly Eeyore.

Before you replied I went ahead and wrote a function to evaluate the rotation of the column by evaluating the solid; something I knew I could do but was trying to avoid for efficiency. I figured evaluating the solid would be a foolproof method that wouldn't be impacted by project rotations and such. My "foolproof" method actually gave me the exact same result as the location point rotation value. This made me go back and reevaluate some of my assumptions. I made assumptions regarding which side of the column is the length and which side is the width. This is why my column is rotated exactly 90 degrees. We all know what happens when we assume...

Thanks for taking the time to reply. I'll try to be more thorough before reaching out next time.

Sean

[jeremy_tammik]

Congratulations on solving it. Yes, i have made all too many such assumptions in my time as well, I recognise the feeling. No problem, no need whatsoever to apologise, and glad I could help.