gbXML export to Trace700: wall geometry problems

[brian.zellmer]

Hi. First post.

The data made its way into Trace700 mostly fine but there are two main problems I noticed immediately:

1. The wall heights of all my rooms are set too low (8'-0"). Does anyone know which parameter in the Revit model correlates to wall height? Is this something our architects should be trained about?

2. The export/import translation completely misses the boat on handling walls. First, it gives me exterior walls on interior rooms, even though the wall Properties dialog indicates they are interior. Second, for almost every room it seems to think there are many tiny walls even when there is really only one (or even none) - sometimes as many 10-20 walls in one room, in all 4 directions. Does anyone have an tips on how to correct this? It seems like a pretty basic function.

(and I already know better than to ask about importing room names - grrrrrrrr.)

Thanks,
Brian

[kyle.bernhardt]

Brian,
Check our Green Paper on using Revit for Building Performance Analysis. I posted a thread previously on it, http://forums.augi.com/showthread.php?t=60687.

Cheers,
Kyle B

[brian.zellmer]

Brian,
Check our Green Paper on using Revit for Building Performance Analysis. I posted a thread previously on it, http://forums.augi.com/showthread.php?t=60687.

Cheers,
Kyle B


well, no progress on this.

for experimenting & training purposes i tried another export on a different project that was done much more thoroughly by our architect and i'm getting the exact same two basic problems i described above.

i don't really see how to resolve this unless i dig very deeply into Revit Building to understand the architectural procedures and how they correlate to the garbage i'm getting from the export (which i don't think should be my job).

and Kyle, i'm sorry to report this paper did not address either of my issues.

so i'm left to simply hope i retire before i have to use Revit on a real project.

[kyle.bernhardt]

Sorry you're having such issues.

I'm surprised the White Paper doesn't address your concerns, from my reading of your stated issues, it seems like it would have. Did you read all of it?

I'll give it a shot.


1. The wall heights of all my rooms are set too low (8'-0"). Does anyone know which parameter in the Revit model correlates to wall height? Is this something our architects should be trained about?

The heights of walls in the Analytical Model depends on the height of the Room that those walls bound. If the Room Upper Limit is the next level, you should be okay, if it's at the default height, 8', you'll get short walls. We cover this in page 9 of the White Paper. Cutting a section of the Room and Turning on Room visibility can help you visualize this in RAC, or just isolating the room in the RME Heating & Cooling Loads dialog.


2. The export/import translation completely misses the boat on handling walls. First, it gives me exterior walls on interior rooms, even though the wall Properties dialog indicates they are interior. Second, for almost every room it seems to think there are many tiny walls even when there is really only one (or even none) - sometimes as many 10-20 walls in one room, in all 4 directions. Does anyone have an tips on how to correct this? It seems like a pretty basic function.

The number of surfaces in the Analytical Model that represent a wall in Revit depends on the shape of the wall as well as the room adjacencies.

The way that gbXML works, walls are converted to flat surfaces. So, if a wall is curved in Revit, it is going to convert into multiple Surfaces in the Anlaytical model. We cover this on page 3. In other complex wall situations, like Curtain Walls, we will also create many surfaces to represent a wall.

The Room Adjacencies also impact how a wall is represented by surfaces. This is explained pretty well on the top of page 4. In short, there will be multiple surfaces for one wall if it has multiple rooms (more than 2) adjacent to it. We have to account for situations where the conditions are different among the different rooms, as we cannot model heat transfer with different conditions on the same side of one surface.

As I've said before on this one, a good architectural model is the only way to really be successful with this workflow. As my professor in college used to say, **** in...**** out. I also think this is something that is new to most, and requires a commitment of time to understand and gain experience. Only then are you going to be successful.

Hope that Helps,

Kyle B

[buzz]

Here is what I did to fix this problem...

I export as gbxml from Revit... For whatever reason, it decides to put the Room Number under "Name" and the Room Name under "Description"...

...so, I open up the .xml file with wordpad (or other editing program)

Menu > Edit > Replace

Find what: "</Name><Description>"
Replace with: " - "
click Replace All

then...

Find what: "</Description>"
Replace with: "</Name><Description>Dang Revit, this is a description, not a roomname</Description>"
click Replace All

Then save the xml file and import it into HAP or Trace - It should bring in the spaces with the space names in the format of "101 - Office"

-Buzz