Results 1 to 4 of 4

Thread: Aligning Linked CAD file to Revit Project?

  1. #1
    Member
    Join Date
    September 14, 2012
    Posts
    84
    Current Local Time
    04:46 AM

    Aligning Linked CAD file to Revit Project?

    Ok I traced over an Imported cad file (did a partial explode on it) in Revit to create a 3D revit model of the CAD file. Now I was told that I could just use a linked CAD file instead of import, so now I'm trying to line up the linked cad file (deleted the import) with the revit model wall corner at the bottom-left most point in the drawing - simple, right?
    You would think so, but for whatever reason revit won't let me snap to endpoints in the linked CAD file, either to move the linked cad geometry to the revit model or the revit model to the linked cad geometry.

    Also, when importing the linked cad file in the first place, it won't let you snap to endpoints on the revit file, and it won't let you snap the autocad origin (0,0,0) to the project base point in revit, either. 100% non-intuitive, which is rare for revit but wtf? I realize there is a bunch of tutorials on "shared coordinates" or whatever, but this is just a small building which isn't even a real project its for learning and theres no site plan or any of that, just walls and doors.

    Surely there is a way to do something as utterly simple as aligning a linked cad point to the revit model??

  2. #2
    Forum Co-Founder Twiceroadsfool's Avatar
    Join Date
    December 7, 2010
    Location
    Dallas, TX
    Posts
    4,403
    Current Local Time
    11:46 PM
    Quote Originally Posted by lukewallace1990 View Post
    Ok I traced over an Imported cad file (did a partial explode on it) in Revit to create a 3D revit model of the CAD file. Now I was told that I could just use a linked CAD file instead of import, so now I'm trying to line up the linked cad file (deleted the import) with the revit model wall corner at the bottom-left most point in the drawing - simple, right?
    You would think so, but for whatever reason revit won't let me snap to endpoints in the linked CAD file, either to move the linked cad geometry to the revit model or the revit model to the linked cad geometry.
    Im not sure why that is... it works fine here. I can snap to the endpoints and midpoints of elements in the CAD files all day long, including in the move command. Are you sure your snaps in Revit are turned on?

    Also, when importing the linked cad file in the first place, it won't let you snap to endpoints on the revit file, and it won't let you snap the autocad origin (0,0,0) to the project base point in revit, either.
    Yes, it will. When you bring it in you have a bunch of options: Center to Center (pretty uesless unless you plan on moving it again), Origin to origin (which is, uh, exactly what youre trying to do above), By Shared Coordinates (which is more correct, once you know how they work), Cursor at Center (pretty useless unless you want to drop it and move it) , and cursor at origin (again, works fine for what you want to do).

    100% non-intuitive, which is rare for revit but wtf? I realize there is a bunch of tutorials on "shared coordinates" or whatever, but this is just a small building which isn't even a real project its for learning and theres no site plan or any of that, just walls and doors.
    Shared Coordinates (or whatever) are not something to sip over because you deem them not necessarily while learning. Its something i would learn immediately, if you *really* care about aligning a CAD file to a Revit model. Project size and scope has little to do with it. Shared Coordinates is what you should be using to align to your CAD stuff, imvho.

    BTW, if you imported a CAD file and exploded it, you should completely start over. That has longstanding repurcussions in a Revit File. If its *just a training file* so *you dont care about doing it right* thats one thing, but doing that in a real project is a bad idea.


    Surely there is a way to do something as utterly simple as aligning a linked cad point to the revit model??[/QUOTE]

  3. #3
    Member
    Join Date
    September 14, 2012
    Posts
    84
    Current Local Time
    04:46 AM
    Thanks for the reply twiceroadsfool (hey I grew up near Dallas), I'll try to play around with it to get it working and edit this post soon, but I wanted to verify that the linked cad import "origin to origin" actually is supposed to import the 0,0,0 point in autocad to things like the survey or project base point in Revit, because for me, it imports the bottom left most point in the entire drawing as a large bounding box into revit. So even if I have a corner of a wall on the origin in AutoCAD, if there are notes or tags to the left of the origin, then that will throw off the alignment of the "origin to origin" placement.

    I also tried the shared coordinates, and that seemed to work the best, although somehow the ceiling grid and all elements were off by some super small margin which is annoying (like 21/256" or something like that).

    I realize that's not enough information to help me but just wanted to report what's going on

  4. #4
    Forum Co-Founder Twiceroadsfool's Avatar
    Join Date
    December 7, 2010
    Location
    Dallas, TX
    Posts
    4,403
    Current Local Time
    11:46 PM
    Well, there are a ton of possibilities. Are you getting a *warning* when you import it? (yellow box bottom right hand corner). Revit wont allow CAD files if the CAD files have exrtemely large extents, and in some cases it will tell you *i am forcing you to use center to center instead of OTO because of the size of this cad file* and then it will do just that, which will toss your stuff right, as you describe. Because *stuff* to the left of any origin doesnt move the origin... it moves the center.

    Trust me, if you have it working correctly, it works perfectly. We do it all day long.

    But its also worth mentioning that CAD and Revit dont really play super well together. They play okay together, but goofy fractional dimensions is part of the game, particularly if you start using very small angles, like offseting property lines that were drawn from legal descriptions in AutoCAD. Bring those in to revit and offset them for a building design, and youll probably be in a world of dimensional hurt.

Similar Threads

  1. Linked Revit File - Show In More Detail
    By domsib in forum Architecture and General Revit Questions
    Replies: 4
    Last Post: November 2nd, 2012, 01:33 PM
  2. Architects file linked into Interiors File
    By Patrick in forum Architecture and General Revit Questions
    Replies: 1
    Last Post: July 2nd, 2012, 09:25 PM
  3. Linked Revit file hatch pattern isn't showing?
    By kcaparella in forum MEP - General
    Replies: 3
    Last Post: January 11th, 2012, 05:05 PM
  4. Insert a Linked Revit File
    By dzatto in forum Architecture and General Revit Questions
    Replies: 10
    Last Post: May 1st, 2011, 07:08 PM
  5. Insert linked revit file
    By redmonki in forum Architecture and General Revit Questions
    Replies: 2
    Last Post: January 7th, 2011, 02:30 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
  •