« Multi-user editing for DWG files | Main | Brief Interview with John Fox about Solid Edge ST9 »

Sep 12, 2016


Kelly Janz

RFA files are Revit families - the equivalent of AutoCAD blocks and can be whatever size the family requires. RFA families are used inside the host RVT file and cannot be used alone.

Kelly Janz

It would be huge if the software could take AutoCAD entities (especially text and Mtext blocks with leaders) and translate them to true Revit entities. For firms with large existing libraries of details, the current best Revit practice is to redraw in Revit over top of the DWG link. Ditto for the standard CAD details that manufacturers offer on the web. Inserting the DWG and then exploding it is a nightmare. Even just linking the DWG into the RVT does not give 100% visual compatibility (specifically with text and polylines). Autodesk doesn't seem to care and the bumpy road between DWG and RVT does not seem to have improved significantly in the past 5 versions, so the road for a third party tool seems wide open at this point.


What about the precision problems? DWG is much more accurate than rvt. Also the design extents mismatch.

Ralph Grabowski

What the ODA is doing is a way to read and write Revit files. It is not a translator to and from DWG.

OTOH, PDF is not particularly accurate either, but it seems to do well enough in the CAD world.


"What the ODA is doing is a way to read and write Revit files. It is not a translator to and from DWG"

Interesting. So, the revit file will exist in the dwg editor built using Teigha tools... be edited by the dwg editing tools and NOT translate the revit file into dwg format?

If so, this seems a bit unwieldy. Most users would convert the revit file once and either XRef the Revit file in dwg format to avoid having to wait for the conversion every time; or convert and edit the revit elements in dwg.

PDF is a good comparison. You would only use PDFs as a graphic background. Apparently only single precision. It is not used as a primary source of information.

Apparently, revit won't display lines shorter than 1/32in. I suppose this is not a problem for a Teigha user in a dwg environment, but what happens when he saves to revit format? All those fine screw threads would disappear? Or would the dwg info be preserved in revit file for later use?

It would be interesting to see how this is handled.

Ralph Grabowski

It is up to ODA members to decide what they want to use the new Teigha BIM API (aka Revit API) for.

So far, the ODA has heard that they want to use it to run external programs that make use of the data stored in Revit files. Right now, these programs have to run inside Revit, which requires a Revit license.

Doing drawing translation between DWG and RVT is a possibility but not the #1 use-case.


I understand the need to be able to interact with Revit files but I don't understand why this is under the "Teigha BIM" label. To be BIM compliant in any way you have to be able to interact with a BIM model and that means .ifc or .ifcxml - Revit is just not relevant in this context.

Ralph Grabowski

My guess is that the ODA cannot use 'Revit' in the name (Autodesk has been very litigeous) and 'BIM' is recognizable to the people in our industry who need to know what Teigha BIM does.

Alexandros Bertzouanis

Is that still applicable? Could anyone provide any information about how to access the binaries of rtv and rfa files? The http://teigha.com/ site is not currently working.

Ralph Grabowski

The site to visit is www.opendesign.com

Ralph Grabowski

Dear Grabowski,

I received the following email after registering to your website.

I am looking for ways of reading or writing a Revit file formats.

Could you please provide any information regarding the above and if there is any documentation available?

Kind regards,


Alexandros Bertzouanis​Computation SpecialistWilkinson Eyre Architects33 Bowling Green LaneLondonEC1R 0BJT: +44 (0)20 7608 7900E: a.bertzouanis@wilkinsoneyre.comW: www.wilkinsoneyre.com
Coronavirus (COVID 19): WilkinsonEyre has now put in place remote working arrangements for all its employees. If you wish to contact us, please call our normal switchboard number and our reception team working remotely will be happy to assist you. WilkinsonEyre are committed to the health and safety of our staff, clients and their families as well as our responsibility as a business in preventing the further spread of the virus. We will continue to monitor the situation and respond to further official advice as necessary.

From: Grabowski <grabowski@telus.net>
Sent: Friday, September 25, 2020 11:45 PM
To: reply-3P3N5JFXYNZI_6RZCG4D3UA2E@typepad.com <reply-3P3N5JFXYNZI_6RZCG4D3UA2E@typepad.com>
Subject: Re: [WorldCAD Access] Alexandros Bertzouanis submitted a comment to "Exclusive! Open Design Alliance opens up the Revit file format"


The site to visit is

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Your comment could not be posted. Error type:
Your comment has been saved. Comments are moderated and will not appear until approved by the author. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.


Post a comment

Comments are moderated, and will not appear until the author has approved them.

Your Information

(Name is required. Email address will not be displayed with the comment.)


Search This Blog



Thank you for visiting!