Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: Coordinates Errors

  1.    #1
    Forum Addict GMcDowellJr's Avatar
    Join Date
    December 21, 2010
    Location
    Phoenix, AZ
    Posts
    2,830
    Current Local Time
    02:14 AM

    Not allowed! Not allowed!

    Coordinates Errors

    I noticed something in a recent file that got me headed down a "what the hell is going on" path.

    It started with a civil file that had all sorts of issues and I had been assuming the issue originated and was isolated to the use of the DWG but I'm seeing the same thing in a new project based on no templates.

    Click image for larger version. 

Name:	coordinates error 01.png 
Views:	27 
Size:	21.7 KB 
ID:	39148

    in this file i created some lines for reference about the Revit internal orgin (RIO -- this is in 2018, BTW so we're at the "default location") and copied them over as shown with Units set to decimal feet to the 12th decimal. So far, so good. The spot coordinate relects the corrrect value.

    However, as I start to increase the distance from the survey point (currenlty at the RIO) to larger values, as might/will occur in locating a project relative to the civil file, we start getting what I assume to be rounding errors.

    Click image for larger version. 

Name:	coordinates error 02.png 
Views:	20 
Size:	22.8 KB 
ID:	39149

    And if i put the Survey Point where it belongs relative to the civil file the errors get more prounounced.

    Click image for larger version. 

Name:	coordinates error 03.png 
Views:	22 
Size:	24.5 KB 
ID:	39150

    So what gives? Before I tried the example in the first image I thought perhaps Revit was converting the decimal feet to rounded (to the nearest 1/256") imperial units but if that were the case then we should see those same error at 10feet from the SP as well.

  2.    #2
    Forum Addict GMcDowellJr's Avatar
    Join Date
    December 21, 2010
    Location
    Phoenix, AZ
    Posts
    2,830
    Current Local Time
    02:14 AM

    Not allowed! Not allowed!
    2020 has the same issue, FWIW.

    Click image for larger version. 

Name:	coordinates error 2020.png 
Views:	14 
Size:	13.2 KB 
ID:	39151

  3.    #3
    Administrator Twiceroadsfool's Avatar
    Join Date
    December 7, 2010
    Location
    Dallas, TX
    Posts
    11,163
    Current Local Time
    04:14 AM

    Not allowed! Not allowed!
    Wait: You moved the Survey point far away, to create that... Or left the SP at the RIO, and moved all your stuff a mile away?

  4.    #4
    Forum Addict GMcDowellJr's Avatar
    Join Date
    December 21, 2010
    Location
    Phoenix, AZ
    Posts
    2,830
    Current Local Time
    02:14 AM

    1 Not allowed! Not allowed!
    moved the survey point using Specify Coordinates at a Point -- the PBP is sitting at the RIO

  5.    #5
    Administrator Twiceroadsfool's Avatar
    Join Date
    December 7, 2010
    Location
    Dallas, TX
    Posts
    11,163
    Current Local Time
    04:14 AM

    Not allowed! Not allowed!
    Cool, cool. Was misreading the post, at first.

    So, if you do it in a blank file, but do SCAP *before* you move and dimension the objects, does it still behave that way?

    Ive seen the last digit get slightly whacked like that if there is any rotation of True North as well (which is damn always), so the very last decimal, i dont pay much mind too.

  6.    #6
    Forum Addict GMcDowellJr's Avatar
    Join Date
    December 21, 2010
    Location
    Phoenix, AZ
    Posts
    2,830
    Current Local Time
    02:14 AM

    Not allowed! Not allowed!
    yes - same issue --- i know that past even 4 decimals we're talking about things that can't be measured in the field but i'd hope that wouldn't matter

    if i take it to 9 decimal places the issue "goes away"

  7.    #7
    Mr. Revit OpEd
    Join Date
    December 14, 2010
    Posts
    3,188
    Current Local Time
    02:14 AM

    1 Not allowed! Not allowed!
    If I use SCaP I always assign the project units to the same as the values I am going to provide. If six decimal places I set it to the same. If I leave the units set to feet and fractional issues then I see some rounding occur. It's worse when the number of decimal places is increased. I find that playing the units game stores the values faithfully even if I switch back and forth after using SCaP. I've never had to do that for Acquire Coordinates, it seems to capture the values and store them consistently without rounding per current units.

    Generally I only worry about six decimal places, everything past that is so small it will never materialize IRL.

  8.    #8
    Administrator Twiceroadsfool's Avatar
    Join Date
    December 7, 2010
    Location
    Dallas, TX
    Posts
    11,163
    Current Local Time
    04:14 AM

    Not allowed! Not allowed!
    Most fo the folks on site that i work with ask for between 3 and 6, as Steve said. I push the accuracy all the way down like that, id im trying to work out a CadKink, somewhere in the model. But yeah, that last decimal is just a gnats ass.

  9.    #9
    Forum Addict GMcDowellJr's Avatar
    Join Date
    December 21, 2010
    Location
    Phoenix, AZ
    Posts
    2,830
    Current Local Time
    02:14 AM

    Not allowed! Not allowed!
    of course it is -- and, like you two, i'd never show anything past 3-4 (or whatever)

    what concerns me is that this looks like a CadKink but it's not and that's going to make convincing others who don't beleive (or who don't want to beleieve) there are issues with DWG in Revit -- if the one thing I can use to show people that Revit doesn't like DWG happens without any DWG in the model well then WTF?

    seems there's more challengs with Revit's math engine than I thought

  10.    #10
    Mr. Revit OpEd
    Join Date
    December 14, 2010
    Posts
    3,188
    Current Local Time
    02:14 AM

    Not allowed! Not allowed!
    Are the lines you are using actually that far from the IO now?

Similar Threads

  1. Worksharing Errors - 2018.3.1
    By jsnyder in forum Architecture and General Revit Questions
    Replies: 9
    Last Post: December 19th, 2018, 01:06 PM
  2. Site Setup - Acquire Coordinates vs. Specify Coordinates at a Point
    By Mel in forum Architecture and General Revit Questions
    Replies: 0
    Last Post: September 7th, 2016, 11:03 PM
  3. Worksharing Model Errors
    By RLBishop in forum Architecture and General Revit Questions
    Replies: 4
    Last Post: December 4th, 2015, 05:01 AM
  4. Installation Errors
    By wjnaim in forum Architecture and General Revit Questions
    Replies: 3
    Last Post: August 4th, 2011, 02:44 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •