Revit DWG Export

Some Background
In the firm I work for, we do not have a person who works on developing revit.  The task of bringing/keeping revit up to date is put onto the engineers working in it.  There are good and bad things that come out of doing it this way.

One of the good things is that the engineers know exactly what we want and how we want it to look.  As we learn more about revit, we learn what it can and cannot do.

The bad... well the bad comes when we get really busy with engineering work (which recently we have been lucky enough to be).  This means we no longer have the time to develop/update families or other standards.  This also means, for the sake of time, we sometimes will do some of our drafting in AutoCAD.  We may do our plumbing and/or hydronic plans in AutoCAD.

The problem comes when exporting the architectural or mechanical background into AutoCAD.  Each update we would need to change the layers in autocad to match our standard plot line weights.  Every background update, it took us A LONG TIME to update the backgrounds in AutoCAD.   That is until export setup was found.

Export Revit to AutoCAD

The file that Revit looks when exporting is a tab delimited text file.  I would recommend editing the file in excel.  I started with the text file named "exportlayers-dwg-AIA.txt".  This file was found at C:\Autodesk\RME 2012. 

- Start by copying the AIA file and naming it something new (I just replaced "AIA" with my companies initials).
- Open the file with excel.
- The columns are as follows
    - Column A:  Category Name (Do not change)
    - Column B:  Subcategory Name  (Do not change)
    - Column C:  AutoCAD Layer name (These can be changed, I just left the layer names as the default.)
    - Column D:  AutoCAD Color  (Change to desired color)
    - Column E:  Cut layer name (I left as default.)
    - Column F:  AutoCAD Color  (Change to desired color)
- When you are finished editing, go to File>Save as... -  Make sure to save the file as type "Text (Tab delimited).
- Open desired revit project.
- Go to a plan view.
- R > Export > CAD Formats > DWG
- Click on the ellipsis to the right of the "Select Export Setup".

- On the layers tab, load layers from standards.  Navigate to file saved above.  Click open.  The file should change the Color ID column to your desired color.
- Change the Export layer options to "Export all properties BYLAYER, but do not export overrides".  If this is not done, I have had problems with some items will not appearing correctly in AutoCAD.
- You can now save this export setup by clicking on the symbol, on the bottom left of the window, that looks like a page with a star.
-  Select the drawings you would like to export.
- Click Next...
- Choose a location, name the file, and I like to uncheck "Export view on sheets and links as external references".

Done!

Feel free to ask me any questions.  I would be glad to help.

Next post... Imported/Linked AutoCAD line weights.

Halftone / Underlay

Halftone / Underlay settings in Revit are a fairly useful tool in getting a model to appear properly.  These settings (found at Manage>Additional Settings>Halftone/Underlay) allow you to set new line weight, line style, or adjust the brightness of objects set as an Underlay.

Revit will automatically apply these settings to items outside of the current view's "Discipline".  For example, if the discipline is set to "Mechanical" then the architectural background automatically utilizes any overrides set in the Halftone/Underlay settings.

Another way to set this (New to Revit 2012) is to go to VV > Revit Links tab and click the box for "Underlay" for each background you would like to use the settings used in Halftone/Underlay. 

A couple of notes:

• If an item is set to halftone, and no underlay overrides are used, the line weights will still be applied.  Good, or bad, this will allow Object Styles, Visibility Graphics settings, and filters to determine the line weight.
• If you want a linked model to show up with the same line weight or pattern throughout, override the weight in pattern in the Underlay settings.
• Regardless of if you check the box in the Revit Links tab of VV.  Items outside of the view discipline will utilize the Halftone/Underlay settings. 
• If you have set model categories (in VV) to halftone, the tone can be adjusted using the Halftone/Underlay settings.

Phasing Graphic Overrides vs View Filters

BACKGROUND

In our AutoCAD system every mechanical item had three different line weights depending on the "phase". New is thicker than demolished; demolished is thicker than existing.

New and existing architectural items were different line weights, but were both lighter than any mechanical item.

ENTER REVIT!

In Revit MEP 2012, there are 4 ways to set an items (such as ductwork, or equipment) lineweight. I have listed below the 4 ways. As you move down the list, the items above are overridden. (Note: each of these will override graphics of a linked model if the model has "Display Settings" of "By Host View")

• Object Styles: These are your base settings for the entire project. If no other overrides are applied, all objects will appear at the line weight, color, and pattern listed here. These can be edited by going to Manage > Settings Panel > Object Styles. They can also be accessed through the "Visibility/Graphic Overrides" window. At the bottom left of the window, click on "Object Styles..."


• Phase Graphic Overrides: These apply to the entire project. These can be used to directly override your graphics for items that are existing, demolished, new, or any other phase you decide to create. This will override Object Styles. These can be found by going to Manage > Phasing Panel > Phases - Graphic Overrides Tab.


• View Filter: These only apply to the current view and therefore, must be applied to each view.View filters can be used to override objects by parameters in the object (i.e. System Classification, Mark, Type, etc.). These can be useful if you, say, need your exhaust ducts to show up thicker than your supply.


• Graphic override by element: Individual items can be overridden. This is done by clicking on the element and going to Modify > View > Override Graphics in View (looks like a paint brush). This is extremely useful when trying to get individual items to show up correctly. Think of it as a touch up tool.

PROBLEM

Here is my problem. Our... more experienced engineers want the existing ductwork to show up lighter and a thinner lineweight than supply ductwork. That would be easy to do if they didn't also want the return to show up thicker than the supply.

TEMPORARY SOLUTION

I hope there is a better way to do this, but this is how I have fixed the problem.

Object Styles: No overrides
Phase Overrides: Existing items are overridden to show up a tone of grey (127-127,127).
View Filter: I have used the view filters to filter supply ducts and return ducts separately. This allows them to be different line thicknesses. No override is done for color to allow the phase override to be applied.

The reason I call this a "Temporary Solution" is that the existing duct now appears at the same line thickness as the new duct. The project must be printed in grey scale for the difference in color to matter.

Other links: Revit Object Graphic Controls