I have a polygon in DWG format (a building footprint) and I want to extrude it in Houdini.

first, i exported it in Autodesk as a DXF format file.

then, I imported this DXF polygon in Rhino and exported it in igs format (because import this DXF file in Houdini doesn't work).

thirdly, i imported this igs format polygon in Houdini.

However, it doesn't seem to be a normal polygon exactly because I can't choose or group some of its faces, and it doesn't look like a normal polygon in “flat wire shaded” viewing mode.

How should I convert this imported igs polygon to a normal polygon?

or What's the best way to import DWG file to Houdini?

please see the attached file for the problematic houdini file and the igs file imported.

Thanks!

it's because igs/iges contains nurbs surfaces
so you need to convert it to polygons first
append Convert SOP, and maybe check Interpolate Through Hulls in it
then polyextrude

thanks, tamte!

But when I added a convert sop and check the “interpolate through hulls” option after the xform node, the resulting polygon is till not a normal polygon…

did i miss anything?

dear tamte, here's the houdini file with the convert sop added.

can you help to take a look why it doesn't work?

thank you very much!

Unfortunately Oat there isn't much to work with in your iges file. The only thing that transfer over was the outline. If you use the MMB on the File sop you will see all your groups are empty accept, “Existing_Building_Outline_Active”. You have essentially just a single polygon, so there is nothing to edit accept the perimeter points.

What was wrong with the dxf file? Can you convert it to a .obj file instead?

there was some Cd primitive attribute which was coloring the whole thing to yellow making it impossible for me t see anything so i deleted it with Attribute SOP
i also added Facet SOP at the end to cusp some faces by angle

Thank you so much, tamte! it works!

And to probbins, I got problem with dxf file is that after importing the dxf file exported from autocad, i got nothing in houdini…. but will try the obj file format later. anyway, thanks a lot!