Friday, May 21, 2010

STRIP REFERENCING & Exporting from Revit to CAD (AND back) V1.0

This document outlines the processes of
  • Exporting Revit to CAD
  • Matching Revit output in CAD
  • Detailing in CAD to reimport to Revit
  • STRIP REFERENCING (For Reimporting to Revit)



Cad Export Process (After bare-bones & Materials are assigned)
Revit Icon> Export> CAD Formats > DWG


































Select set to export (Or Insession)


Select sheets/views to filter in the list. Sort by name to itemize everything by drawing type and its name


Set up CAD Layer naming (If not already set)




This may require selecting one of the read-only layer exports and resaving it under a different Name. Revit ADDS ALL LAYER NAMES from linked drawing files- to prevent this list from becoming too large we made it read only.


Strip everything off the 'tail' of the file name so the project number (and building identifier if necessary) are the only  elements left to use as a prefix. Revit will add a "-" after this prefix.


Make sure the [ ] Xref views on sheets is unchecked. This places all elements with the sheet in one file.


*If files and borders are to be xrefed for continuity- editing in CAD must be done to setup the xbdr files and other base files.


You can then use Renamer to further clean up and refine the file names (If you have several to do at once) A preset for Bay Pines exitst here:
S:\Healthcare\3683a-00 VA Bay Pines\2.0 Drawings\2.4 Revit\4.0 Publish\4.3 DWG\4.3.1Renamer_Presets\03683a-00-VA_BAY_PINES-new.rnp


Mass-renaming of files should only be attempted by those who are certified to use it. If you have any questions or need someone else to clean up the DWG file names contact Ron Allen (Apsis0215@gmail.com)



When exporting to CAD Revit creates PCP files containing the pen weight information. As there are a number of customizations that occur in Revit between differently scaled views. (Need validation - Test  to see if the best option to maintain visual fidelity may to use the PCP file for the sheet layout.)


STRIP REFERENCING
On exporting from Revit [  ] xref views on sheets should be selected to create separate drawing files to reference back into Revit.


Detailing in cad is intended to enhance the elements in those files using the elements as markers and locators when Revit resources are not available and CAD is the only resource available or is an only option.


Under no circumstances should the original location or base points in the drawing file be changed or the elements relocated in the file. The base points should ensure critical for re-referencing will match when the CAD files are brought back into Revit. (Need validation multiple tests to verify  origin-to-origin matches back up in Revit details)


If STRIP REFERENCING is not being used- this sub-section can be skipped. To use STRIP REFERENCING (for bringing the enhancements back into the Revit views:
  • Renaming utilities should be avoided as this will upset the link reference back to the original Sheet references exported from Revit to CAD.
  • Open an individual detail file
  • Save the file back out appending "-CAD" to the end of the file name. (IE "03683 - IDT3‑1G-301T - CASEWORK-CAD.DWG"
  • Move all the line work and hatching from the file away from the original location- this will be used for quick reference and eventually deleted.
  • XREF the original detail file (ie "03683-IDT3‑1G-301T-CASEWORK.DWG") back into the drawing as an overlay


Detail over the elements using:
  • The layers exported by Revit
  • The line types exported by Revit
  • The hatch patterns exported by Revit


Avoid the use of:
  • Masking regions
  • AEC Objects
  • Objects requiring proxy elements in earlier versions of AutoCAD. Proxy objects don't always translate. Keep it simple.
  • Match text styles, heights and dimension styles if possible


The "–CAD" version of the file should x-reference back into the CAD sheets at the same origin point in model space.


The -CAD version of the file should also reference back into the Revit drawing detail as origin-to-origin. This will bring in the additional detailing from CAD over the Revit detail. Because the views were exported as x-refs from Revit- the titles of the CAD files should match the view titles in Revit.

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