Archicad 3D model export to CATT acoustic software

[judeswings]

Hello!

I am currently trying to export a 3D model of a small room from Archicad to CATT-Acoustic, which only accepts DXF. or .OBJ file formats, but for some reason the 3D model is read as polylines rather than faces/singular surfaces and gives this wonky look.

Here's what I've done so far:

1) I tried saving the file as a .3DS and opening it in Autocad to save it as a .DXF, then converting it in CATT--which gave over 1000 polylines and corners and ultimately made the program crash.

2) I tried converting the 3D model into a morph, saving the file as a .3DS and opening it in Autocad to save it as a .DXF, then converting it in CATT--which gave less polylines than the previous, but still, the program crashed. 

3) I tried converting it to an .OBJ file format, then downloading an extension (obj2catt) to convert it, but that gave a bunch of errors and crashed the system.

4) I tried opening the .OBJ and importing it to my embedded library as a new object in Archicad, then exporting it to Autocad, then CATT.

5) I tried exporting the 3D morph to Blender and Autocad to try joining the polylines or creating a singular planar surface, but since its imported, it couldn't merge them (or maybe I am too inexperienced to figure it out)

and God know what else I've tried...I'm open to ANY ideas PLEASE because every solution I've come up with has given me the same result. 

 

Operating system used: Windows

[Laszlo Nagy]

Why don't you just save an OBJ file from the 3D Viewpoint in Archicad?

[marcoariveross]

[Barry Kelly]

I see DXF in the save from 3D list as well.

Barry.

[judeswings]

I did that in 3), but the surfaces were still triangulated and warped to the extent where the CATT program crashed upon opening the file.

[judeswings]

When I tried opening the saved file in CATT, it was too warped and crashed the system.

[judeswings]

Yes, the problem is that when Archicad exports the 3D model, its exported as a mesh--and CATT is a program that reads/works with planar surfaces. I am trying to think of a program(s) to piggyback off of to easily convert the created model into simple planes.

[CosminF]

A quick google search got me thinking: you can export the file from Archicad into Blender as .fbx or .obj (Blender is open source, free), you can simplify the geometry (apply decimate modifiers to it) and then use a free import/export plugin from Blender to CATT.

It is a very roundabout way to transfer the geometry but it might just work. 

[judeswings]

Hi! I tried that in point 4) but because Blender is also a mesh-based program, it gave me a similiar triangulation result 😕

[judeswings · Accepted solution]

Hi everyone! I eventually figured out a solution--it's a bit more work than preferred, but if you're stubborn and in the same boat as me; here's what I did. 

I exported a DWG file from Archicad to AutoCAD and then I converted it all the elements to surfaces using the CONVTOSURFACE command, so I could see the triangulated model that I would usually get in CATT. I used the MERGE command to manually merge each of the triangulated elements of each individual (!!!!) surface, then I exported it as a DXF and used the 'dxf2geo' import option in CATT. Some surfaces were still triangulated for some reason (floor and ceiling), but majority of surfaces were finally unified and I manually joined the remaining triangulated surfaces in the CATT geo master file. It's not a full-proof method, but it was the most simplified version I could get it.