topic Re: Serious issues importing 3d Cad or IFC file in Revit Structure Forum

Serious issues importing 3d Cad or IFC file

omarekbergvik — Sat, 11 Jan 2020 18:06:32 GMT

Hello,

I've come up against a problem that has consumed many hours of my time and still not getting desired results.

The problem: I have a 3d DWG file that was produced in AutoCad MEP. The file contains a system of pipes I need the geometry of the pipes loaded into Revit. IF anyone knows a good workflow the help me get the geometry into revit I will be forever grateful.

Part of what is so frustrating is that our team uses Navisworks for coordination, and both my model and the MEP model show very nicely in Navis works. But here begins the issues.

FIrst issue. When I load the navisworks file. I cant align to any surfaces, or properly position the model with mine. I believe this is just a general symptom of using coordination files in revit. But this is not really my issue.
THe bigger issue is that when I load any coordination file, dwg, or IFC of the Cad MEP model, the graphics are heavily distorted. so badly that it is impossible to use.

What I have tried so far is - And the result.

Navisworks File - Badly Distorted, Cannot Align
3d DWG - Badly Distorted, Aligns Fine
IFC File - Badly Distorted, Aligns Fine
Importing the 3d DWG as a mass model - Badly distorted

From what I have read on the cad forums, there is most likely a problem with the project origin etc. This project has been modeled in what the Cad manager calls the real coordinate system. Because of this, everyone models have an origin that is thousands of feet away from the modeled information.

To try to combat this problem:

I adjusted the UCS in the 3d DWG using autocad MEP
I also adjusted the project coordinate system in revit.
I also tried linking the same cad file with modified UCS to a new revit project.

No matter what I have tried so far I am still getting these terrible graphics.

The team keeps insisting that the files they are providing me should work and I want to believe them but nothing I try works!!!

Let me show you guys some info from the models I'm working with to illustrate the issue.

First the Beautiful Navisworks Coordination model: (NOTE THE PIPE HAS A FACE ASSOCIATED WITH IT)

Re: Serious issues importing 3d Cad or IFC file

omarekbergvik — Sat, 11 Jan 2020 19:25:51 GMT

Navisworks view:

Autocad MEP View: (note that the pipe is a proxy entity)

The pathetic render found in revit of the same region. It appears that the import doesnt show a solid or a face. But instead a series of lines with very poor resolution that leads to distortion and makes this unusable in revit. This is in 3d views or in plan views.

Im open for any suggestions as to work arounds. I just need to see the pipes clearly in revit.

Re: Serious issues importing 3d Cad or IFC file

ToanDN — Sat, 11 Jan 2020 19:49:31 GMT

You need to export the CAD mep drawing to vanilla AutoCAD drawing in order to link it properly in Revit.

Re: Serious issues importing 3d Cad or IFC file

omarekbergvik — Sun, 12 Jan 2020 18:10:59 GMT

Is there a special command to do this? Using File -> Export -> Autocad -> Autocad 2000 has no effect on the link view in Revit.

I will now export each of the file types possible and see if I can link any of them successfully.... Still no good workflow from Autocad MEP to Revit?

Re: Serious issues importing 3d Cad or IFC file

omarekbergvik — Sun, 12 Jan 2020 19:46:52 GMT

Okay. As indicated in my first Post, I was suspect that the internal origin of the project had something to do with the issue. These models were made to be great distances away from the internal origin (I think this is a poor choice but whatever).

When I tried adjusting the UCS in autocad the problem was not resolved so I moved to looking for other solutions.

Along the way I found that the Object Enabler for Autocad MEP and Fabrication was missing from my build. So I got that which exposed the pipe parameters and properties in both Autocad Vanilla and Autocad MEP.

With this I was able to see, that even though the UCS was moved in the file, the pipework still was defined in the original coordinate system. The ends of the pipe had coordinates with massive values.

Effectively this huge numbers for the coordinates eat up all of the available decimal places in Revits graphical representation of Linked Drawings. So the detail of the pipe was completely lost, causing the problem I reported to be distortion.

THE FIX!

1.) Export from Autocad MEP to Autocad Vanilla.

2.) Make a block with the entire drawing information you want to import to revit. Set the origin of the block close to the geometry.

3.) Make a new 3d DWG file.

4.) Insert the block to the new file at point 0,0,0.

5.) Explode the block.

6.) Explode everything in the file one more time. This releases the pipe entitys and turns them into 3d elements defined in the new UCS. (I know this is usually a bad choice, but see here https://knowledge.autodesk.com/support/revit-products/troubleshooting/caas/sfdcarticles/sfdcarticles/Revit-3D-solids-and-text-are-missing-in-3D-view-when-dwg-file-is-imported-into-Revit.html)

7.) Link to Revit and Align.