I'm relatively new to Houdini and I'm trying to model using an illustrator file as the basis. After a few tries exporting from illustrator, I got the imported curves to show up, but now I'm having a couple other problems.

First, it doesn't seem to recognize compound shapes, so curves with cutouts in illustrator just seem to extrude as separate curves when brought into houdini.

Second, some of the curves seem to be reversed, meaning when I try to add an extrude, they extrude in the opposite direction as all the other curves.

Any idea how I might fix these problems?

Illustrator support is very lame in Houdini (and other 3D apps). You may not be aware of this but most 3D import routines only support illustrator files up to Illustrator 8. Yes, you read that right, only the features that an AI8 file can support. So all those fancy gradient and fill stroke tricks are off the table.

Try saving your file out as a legacy AI8 file. Also make sure you have outlined all shapes and fonts.

Another approach I use is to save the actual illustrator file out as a 300DPI PNG file with alpha (File/Export). Then use a Trace node to read that .PNG file instead of the .AI file. You may also want to follow up the trace with a Hole node to punch out those solid areas (lower the distance tolerance) that are supposed to be hollow, like the center of an “o,p,r,a,e” etc..

I was doing an illustrator trace yesterday, the image shows my node stack.