Exporting to AutoCAD - Problem with Block names

[gurhan]

Hello,

When I export our Revit models to AutoCAD, every single structural column comes with a different block name. This happens for doors and other Revit objects as well. So I have 20 instances of the same column in Revit, but in AutoCAD they are all different blocks with different names. I have searched this issue in the forums briefly, and found out that Revit converts each object with its specific ID number, when it is exoporting to AutoCAD.

I am desperately wondering if anyone came accross a workaround for this? Is there a way to have all the Revit objects exported as copies of the same block, with same block name? I would really appreciate if any one can provide some further insight on this. The subject is very crucial to our work.

We're using Revit for certain tasks in the office and we deliver the construction documents in AutoCAD. Therefore, we frequently export our models to .DWG format. We have our own export settings to match with the CAD standards of the office, so the exported files match with our AutoCAD drawings without any problems.

Thanks in advance,
Gurhan

[JohnCAVogt]

My experience, from the architectural side, was that Revit had to be able to do this, so that a Revit family instance that was partially obscured by some other 3d element could be displayed in the dwg the same as it showed in the Revit view. For example, in an elevation, a window that is partially covered up by something in the foreground has to export as a different 2d block from the one next to it that is displayed with nothing covering it up. So, at least, that partially explains why Revit does this. For me, it exports all instances that appear the same (not obscured by something) as the same block name. It's a goofy name, but they're all the same. Why, for you, it doesn't export all instances as the same block definition in the dwg when they all look the same in the Revit view, I don't know. Maybe something is different about structural, that it thinks each column is different?

[Revitaoist]

Using Revit Arch 2012, I just created a new project and exported 3 structural columns to CAD, and they are all the same block.

[gurhan]

Using Revit Arch 2012, I just created a new project and exported 3 structural columns to CAD, and they are all the same block.


My experience, from the architectural side, was that Revit had to be able to do this, so that a Revit family instance that was partially obscured by some other 3d element could be displayed in the dwg the same as it showed in the Revit view. For example, in an elevation, a window that is partially covered up by something in the foreground has to export as a different 2d block from the one next to it that is displayed with nothing covering it up. So, at least, that partially explains why Revit does this. For me, it exports all instances that appear the same (not obscured by something) as the same block name. It's a goofy name, but they're all the same. Why, for you, it doesn't export all instances as the same block definition in the dwg when they all look the same in the Revit view, I don't know. Maybe something is different about structural, that it thinks each column is different?

Thanks for your quick responses. Revitaoist's comment was helpful to me that I realized I didn't actually indicate that I was referring to Structural Columns those are Concrete. As a matter of fact, yes, when I export "M_Double C-Channel-Column - 2C380X74" steel columns they all come with the same block name in the exported .DWG (which is M_Double C-Channel-Column - 2C380X74-3223-Level 1). However, when I export "M_Concrete-Rectangular-Column - 300 x 450mm" concrete columns they all come with different block names such as:

M_Concrete-Rectangular-Column - 300 x 450mm-2600-Level 1
M_Concrete-Rectangular-Column - 300 x 450mm-V1-Level 1
M_Concrete-Rectangular-Column - 300 x 450mm-V2-Level 1

In reference to JohnCAVogt's comment, I have basically tried to disable the Analytical Model checkboxes for the concrete columns to test if it makes any difference, but the result was no. And I tried this on a clean plan view, in a new project which I created without a template, where no other object was created but only 3 structural concrete columns.

Well, does anyone has any other suggestions?

[david_peterson]

I think some of that reason you're getting so many different names, is that they are different in revit's mind. I'm guessing you're getting a block for each column of a different type and different instance. If they have different offsets from top level or bottom level, you'll get a different block name. It also may be picking up any columns below the floor, as I believe it will export every object within the view's range.
IMHO any drawing you get that's been exported from Revit for use in cad, is just about useless. You get lots of ****, lots of lines over lines....... junk. Yet every client seems to still want cad drawings at the end of the day.

[gurhan]

Thanks for your pessimistic reply Dave ;)

Well, just to clarify I want to add the following: When you open a new project and create three concrete structural columns from standard revit families with all their family, type, and instance attributes exactly the same, they are converted to AutoCAD with different block names.

I realized that, in every instance of a structural column, the column hatch is cropped in a different position. That should be why Revit thinks those blocks should be named separately. This also explains why you don't have this problem with the steel columns. Your comment was helpful for me in realizing that I should ask the question what can be the difference between those instaces. And the difference was in the cropping positions of the hatch pattern. Unless those concrete structural columns look exactly the same in the exported .dwg, they will be named differently as CAD blocks.