Wednesday, January 16, 2008

Project North / True North

This has always puzzled me and wanted to find out if anyone else out there felt the same. When setting up a project you do not always know what project north will be on new construction project. The default orientation though for Revit is set to Project North.

So, basically to get things setup correctly from the beginning I have to put in the property coordinates from the surveyor, test out options to figure out the building orientation, rotate the entire project so that it lays out correctly on the sheets, set the view properties to True North and then finally go to Tools > Project Position / Orientation > Rotate True North.

Is it me or is this set backwards? Does anyone out there have a good reason why it is acceptable as it is currently set-up? Is this something that the Revit development team can fix? Kinda like the Ceiling misspelling on a tab that took them a few releases to fix.


Aaron 1/17/2008 4:59 PM  

Try this: start a blank project. (Model some walls.)

Go to a plan view. Set it to be oriented to true north. (Nothing changes because proj N = true N).

Throw in a stock north arrow symbol. Rotate it some arbitrary angle E or W.

Now, pretend this represents true N. Invoke the Rotate True North tool. Move the center of rotation to the N symbol and snap first to the symbol's north, then to straight up on your screen.

Your N symbol should now point straight up. You just rotated true north. I wouldn't say this is backwards, but intuitively we want to rotate "up" to match true N, not the other way around. I hope this clears it up a bit. I find it extremely helpful to have an actual representation of the north direction to rotate.

Also, If you have a site (true north up) linked in (.rvt or .dwg), you can just rotate it to suit your building (as your site design develops), and then acquire its shared coord's, the true N/proj N takes care of itself.

Steve 1/24/2008 11:51 PM  


The assumption is that you don't know True North when you start working out a basic plan. Once you get a survey you can start thinking about True North.

So starting out you can be "selfish", make the plan easy to put on paper without concern for the site orientation.

Once you determine the site orientation required you can Rotate True North to define the angle between Project and True North. I posted an article on my blog some time ago that discusses this subject.

This process isn't oblivious to ensuring quality natural light and considering the building's orientation to the path of the sun during the course of a day.

It just assumes that you'll start the concept while waiting for a real survey to be completed. Fwiw, this has been consistent with the projects I've been involved in over the last ten years.

Steve 1/24/2008 11:53 PM  

Sorry Jason, I had the firm firm name in my head when I responded!! 8-(

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