Tips for Importing 2d Dwgs on Revit

7/27/2019 Tips for Importing 2d Dwgs on Revit

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Import AutoCad 2D drawing to your Revit

modelIn CategoryAutoCAD,General

ByVeng

I tired to import an AutoCAD 2D site plan into Revit. It seems pretty straight

forward by going to File > Import/Link > CAD format to bring the CAD file into the

model, until I realized the CAD site plan is located nowhere close to my

model. Why is the CAD file living so far away from my model? Does Revit place

the site plan randomly on the plan view or does it have an origin and the site

plan is located correctly on the plan view?

The answer is YES! Revit does have an origin, if you try to draw a cross at theorigin in AutoCAD and import the file into Revit (in the dialog box, check the box

next toLink*, and underPositioning, select Auto Origin to Origin), you will see

where the origin is. Knowing the origin location is specially important if you are

trying to import several levels of floor plans, site plan, etc., into the model.

Link*

Link box checked- Your CAD file in your Revit model will be updated every time

you make changes to it. You can view your entire list of imported cad files

underFile > Link Manager

Link box uncheckedThe CAD file is inserted into the model instead of

linked. All changes you made to the CAD file will not be updated. You willhave to remove and reinsert the file for the updates.
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I received an email recently from a woman named Monica asking if I would go through the

process of importing an AutoCAD DWG file into Revit and modeling from it. We very often jump

to the very complicated features of software and sometimes ignore the basics, for example, how

to get into the program and start working. So, Im going to go through how to place your

drawing into Revit and start working with it. One thing Id like to suggest, however, is that you

look at one of my earlier posts,Shared Coordinates in Revit (and AutoCAD), which is what Ill

be talking about first. OK, here goes:

Lets take a look at a simple AutoCAD drawing that I wa nt to import (fig. 1):

You can see here that weve just got some walls, doors and windows and theyre all on their

appropriate layer. Now, lets bring them into Revit.

1. In Revit, within a new project, click File> Import/Link CAD Formats.

2. When the Import/Link CAD Formats dialog box appears, after locating the drawing, at the

bottom of the dialog box, check the box next to the word Link.
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The next important option comes from the pull-down menu next to Positioning. The tells Revit

how, and more importantly where, to insert the DWG. If your drawing was drawn in a random

location in AutoCAD, the specific location in Revit is not important so, from the pull-down menu,

you should chooseAuto Center to Center. This also assumes that there are no other

drawings that you plan on importing that might rely on the positioning of the original drawing. If

there are, and your drawing in AutoCAD is close to the origin (0,0), then you shouldchooseAuto Origin to Origin. Again, only choose this option if your drawing in AutoCAD is

close to the origin. If it isnt close to it (and Autodesk refers to anything beyond 1 mile from the

origin as not close) then you should choose Manual Centerand follow the steps in the other

post I referred to above, to acquire the coordinate system from the imported DWG.

3. For this example, were going to chooseAuto Center to Centersince our location is

random and no other drawings will be imported which might rely on its position in space.

4. In the middle of the bottom of the dialog box youll see three more options, the first of which

is Colors. Some people like to choose Preserve so they can easily see that, since objects

drawn in Revit are black (by default), any objects in color came from AutoCAD. Most of the

time, I like to choose Black and White. Choose that.

5. The Layers option allows you to choose which layers from AutoCAD you want to

import. Leave this on the default option,All.

6. Finally, Import Units allows you to specify the units of the drawing being imported. This is

important because Revits architectural units arefeetby default while AutoCADs architectural

units are inches. While you can keep this option onAuto-Detect, I like to set it to inches just to

be sure.

7. Finally, the Place atpull-down menu lets you choose on which level you want your drawing

placed. Well leave this on the defaultLevel 1 as well.

8. Click OKto import the file.

9. Next, we need to create Revit objects based on the imported CAD data. Lets start with the

walls. The exterior walls are 6 masonrywalls. On the Design Bar, click Walls and then from

the Type-selector, choose Basic Wall : Generic6 Masonry.

10. We could certainly trace over the lines from the AutoCAD file, but there is a faster way. To

the right of the Type-selector pull-down, click the Pick Lines arrow.

11. Click the pull-down menu next to Heightand choose Level 2.

12. Next to Loc Line, click the pull-down menu and choose Finish Face: Interior. This is telling

Revit that the Interiorwalls that youll create should remain fixed. In other words, the wall will
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grow to the exterior (which is the line from AutoCAD youll be selecting) if you changed it to a

different thickness in the future.

13. Place your mouse over one of the exterior wall lines until it highlights AND a dashed blue

line appears insideyour sketched walls. In many cases, if you now tapped the Tab key, Revit

would try to select all connected walls allowing you to create all of the exterior walls in one

shot. This feature works better when trying to select more than one connected Revitobject as

opposed to an importedAutoCAD line. Click the exterior line and the new Revit wall will be

created.

14. Repeat this process for all of the exterior walls.

15. Well want to repeat the process again for the interior walls with the wall type Basic Wall :Interior4 Partition (1-hr). Since this is not a wall type built into the standard template file,

youll need to duplicate one of the others and modify its structure. Using the method described

in Step 13, use the Loc Line: Finish Face Interiorjust as before and create the interior walls as

in figure 4 below.
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16. Finally, we need to insert the windows and doors. Since part of the doors and all of the

windows are currently obscured by the newly created walls, click the Model Graphics

Stylebutton at the bottom of the Revit window and choose Wireframe.

17. Place doors and the varying sizes of windows using the object snaps available in Revit.


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18. Once finished, if you no longer need to have the DWG as an underlay, click File>

Manager Links.

19. When the dialog box appears, select the drawing file from the list, and click Remove.

The completed Revit model will look as it does in the image below:

If youve got any questions, please feel free to comment on this post and Ill answer as soon as

possible.

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Tips for Importing 2d Dwgs on Revit