topic Re: ifc export accuracy? in Collaboration with other software

ifc export accuracy?

Anonymous — Thu, 07 Sep 2006 03:15:42 GMT

I created structural model with columns and beams in Archicad 10. All of the beams are lined up and snapped to the corners of the tops of the columns.

I saved my structural model in the IFC 2x2 format to open in CadWork (we use CadWork to produce automated shop drawings for CNC machines).

When I open the IFC file in CadWork, the beams are 1/64" away from the columns in the x and y planes.

I figured out that Archicad has a 1/64" accuracy in it's model units etc.
Is there a setting in the IFC translation or in Archicad that I can change so that the IFC model will open in CadWork and be as accurate and the columns and beams will be lined up as they appear to be in Archicad?

Thanks!

Manny Jasus

Re: ifc export accuracy?

Anonymous — Thu, 07 Sep 2006 14:34:17 GMT

Make sure you are inputing dimensions when placing/positioning things in Archicad. Some users will look at the dimension in the coordinates box/traker and assume it represents the actual dimension (makes sense). Unfortunately this is not the case. Another option is to enable the grid snap and set the gird to 1/2" or whatever works in your situation. This will assure everything is where you assume it should be.

Re: ifc export accuracy?

Chazz — Thu, 07 Sep 2006 15:27:22 GMT

Frightening if true. In fact, this would sort of kill any use of IFC as an interchange standard. Manny, if you look at the relationships in AC, and zoom way way in do you see any of these discrepancies?

Re: ifc export accuracy?

Anonymous — Thu, 07 Sep 2006 16:05:51 GMT

Chazz wrote:
Manny, if you look at the relationships in AC, and zoom way way in do you see any of these discrepancies?

I zoomed way way WAY in and did not see any discrepencies . . . everything appears to be lined up correctly.

But when I save as IFC and open in CadWork, everything is off. Today it is 3/64" off (see screen shots)

And the 3 1/2" wide beams I created in Archicad are 3 15/32" wide.

The 5 1/2" x 5 1/2" post in Archicad is 5 7/16" x 5 15/32" in CadWork.

Re: ifc export accuracy?

Anonymous — Mon, 11 Sep 2006 18:57:57 GMT

Any other thoughts on this accuracy issue?
I don't understand why the beams I created a certain width in FrameWright are now not the same size when I open the IFC file I created. I typed the exact dimensions I wanted the members assuming that 5 1/2" is in fact 5 1/2" . . . if it's not, why should we use Archicad? And who's to say that my 90-degree walls are in fact 90-degrees? If I have a 30 foot wall or beam and I open the IFC in CadWork (or other program) and try to send the data to a CNC machie to cut and notch, then everything will be inaccurate and the precisely milled joints will not fit. Besides this obvious fact, it just looks really messy and is not acceptable to open posts and beams I thought were "tight" and find out they are loosey goosey . . .

anyway, thanks for all the help and suggestions . . .

mjasus

Re: ifc export accuracy?

Richard Morrison — Mon, 11 Sep 2006 19:37:02 GMT

Manny,

Just to check, see if both Working Units AND dimensions are set to 1/64". If you have dimensions set to a "cruder" value than the working units, you may not realize that there is an inaccuracy in the dimension that you are seeing displayed.

Re: ifc export accuracy?

Anonymous — Mon, 11 Sep 2006 19:56:08 GMT

Hi Richard,
Both my Working Units and Dimensions were set to 1/64 before I started modeling. It's still 3/64" off or misaligned when I import the IFC file into CadWork.

Could it be an IFC setting on the Archicad end? Maybe it's translating to IFC less accurately than it should be? I looked in the "IFC 2x Edition 2 Options" (File--File Special--IFC 2x2--Options) and didn't a setting for accuracy or tolerance.

Thanks again for the suggestion. Is there an official Archicad/Graphisoft support email I should try too?

Manny

Re: ifc export accuracy?

Anonymous — Mon, 11 Sep 2006 20:08:01 GMT

Manny,
Here are some e-mail addresses and phone numbers
for Graphisoft US in Boston.
Graphisoft US Tech Support 1-800-238-3992
David Tauer dtauer@graphisoft.com
Graphisoft U.S., Inc 1-617-485-4203
Peter Devlin

Re: ifc export accuracy?

Anonymous — Tue, 12 Sep 2006 14:42:07 GMT

Hi Peter . . .
I sent an email to David with these questions . . . I'll repost when I hear from him.

Thanks for the info . . .

Manny Jasus

AC 10 (trial - 3 days left!)
XP Pro
3.59 GHz
2.00 GB MEMORY
NVIDIA Quadro FX 1400 - 128MB, 256-bit, 19.2GB/sec.
dual 19" Planar PL1910Ms

Re: ifc export accuracy?

Djordje — Tue, 12 Sep 2006 18:43:07 GMT

It is under investigation ...

Re: ifc export accuracy?

Anonymous — Tue, 12 Sep 2006 19:36:07 GMT

Hello Djordje,
This is good to hear. Thank you for letting us know.
Manny has a serious problem and he has put a lot
of excellent effort into trying to solve it.
Also, thank you for getting rid of those posts about card games.
Peter Devlin

Re: ifc export accuracy?

Anonymous — Wed, 08 Nov 2006 15:27:39 GMT

FYI . . .
Cadwork has addressed the IFC accuracy issue.
It was an IFC import precision issue.
They have produced an updated IFC .dll file that fixes this problem.

Now we are able to import Archicad created IFC files in Cadwork and do not have to worry about pieces being misaligned.

Oh happy day!

Manny

Re: ifc export accuracy?

Anonymous — Wed, 08 Nov 2006 18:02:03 GMT

Hello Manny,
That's good news.
Thanks for the update.
Peter Devlin