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Arc Property Lines - HELP!!

Message 1 of 15
2579 Views, 14 Replies

Arc Property Lines - HELP!!

I am trying to use the table to create the property lines for my project. I am having trouble controlling the arc segments. they are not turning like they should be,

I really need to get this done.

Message 2 of 15
in reply to: Anonymous

Why not just sketch the arc property line. But arcs are placed by their chord dimension.

Mel Persin, AIA
AEC Technology Consultant
Technology to Visualize and Realize Solutions
Modeling the Future/Drafting the Past
Message 3 of 15
in reply to: Anonymous

I've had the same problem with arcs. I have tried every order clockwise and counterclockwise to see if it would go in the right direction, but to no avail. I've had this issue on every single site I've tried that had an arc in it. Drawing in an arc solves it visually, but not with any accuracy. Anyone else have this problem that has found a solution??

Message 4 of 15
in reply to: Anonymous

Without seeing what you are trying to create in the Property Line sketch, it is difficult to imagine your problems creating arc segments. Please post an image of what you are working on.

Mel Persin, AIA
AEC Technology Consultant
Technology to Visualize and Realize Solutions
Modeling the Future/Drafting the Past
Message 5 of 15
in reply to: Anonymous

I know this thread is a decade old but I've had to deal with this same problem recently.  Creating a tangent arc is difficult in table entry mode.  I found the solution, and I decided to encapsulate the knowledge so you and I could reuse it in the future.  It turns out that all Revit needs is the bearing angle of the arc cord to create a tangent arc in a property line table. 


I've created a simple Generic Annotation family that serves as a "Tangent Arc Cord Angle Calculator".  You simply enter the radius and arc length to get the angle.  You either add or subtract this angle (depending on if you want Left or Right curve) from the current bearing and you get your arc bearing angle.





Message 6 of 15
in reply to:

Here's an improvement.  The Tangent Arc Cord Angle Calculator now automatically adds/subtracts the chord angle from the bearing angle of the line.  

Message 7 of 15

Thank you for doing that. I used to create base maps for utility companies and I used plats and base of baring all day long. I was pulling my hair out trying to get a curve into a property line. That helped a lot. I wonder, has anyone at Revit ACTUALLY worked in the construction industry?  For example, P-traps! ALL sinks have them. They go in 1 way!!!! no need to rotate them in every axis

Message 8 of 15
in reply to: Anonymous

Hope below link will help addition maintain clockwise direction. 

Message 9 of 15

Thanks for providing this calculator. I am trying to use it and just need more help. If I am drawings a curved property line at with this given information:

Delta symbol= 83d47'37", R=15', L=21.94'

I entered this information on the calculator and I get 2 bearing angles and a cord angle. What do I do with it? In the image below I show the the traverse I am trying to sketch. I start with the 116.61 line and then I want to continue with the R=15 ft. curve that head southwest to another curve property line L=42.00 ft. 


I appreciate your help. Thank you!


Message 10 of 15

Hi There,


In your case, the angle of the cord is 41.90.  The angle of the chord is not the same as the bearing of the cord.  To find the bearing you will need to do some math or just do what I did below and draw a vertical line and get the angle of the chord from the vertical line.  It turns out to be S 0.2deg W.  Plug that bearing into the table (and adjust the R/L as needed) and Bob's your uncle!


tangent calculator.PNG


Message 11 of 15
in reply to: Anonymous

I think you subtract 41°42'21" by 90 and that is the tangency of your arc. 

Message 12 of 15

Hi CADdaddy,

Thanks for explaining the geometry. This is awesome! You also were using your first iteration of the bearing calculator. I was using the revised version. So the angle being entered in the Revit PL table is the difference between the angle between the vertical line and the cord direction - 180 degrees. Correct? Also, are we always using a vertical line to the end point of the previous plotted line? In my example, it was the 116.61 ft. line bearing SE. 

Message 13 of 15
in reply to: Anonymous

I've uploaded an updated version with better usage notes.  You can turn the usage notes visibility off.



Message 14 of 15

Sorry, I can't confirm that method to calculate the bearing angle.  I'd need to refer to my surveying textbook that I sold in 1985!  If you don't have your civil engineering training down cold, just do exactly what I did, physically draw the lines and angles.  No math or guesswork is required:

  1. To move clockwise (as you are indicating on your screenshot) you'll need to convert N 41 43' 22" W to S 41 43' 22" E.
  2. Now draw that cord line at the angle given by the calculator 41.90' (the length doesn't matter).
  3. Now draw a separate vertical line nearby.
  4. Find the bearing angle of your new cord line by measuring the angle from vertical vertical (in your case 179.80).  So the bearing is southward, at 0.2° degrees to the west of vertical...which is written "S 0.2° W".  You type that into the table and Revit converts the angle to minutes and seconds, S 0 12' 00" W.


Message 15 of 15

Great! Thank you! You have been very helpful. It's been more than 20 years since my site planning course in grad school. 

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