@skyways128 said:

@ Jim: I emailed my client, but he hasn't replied yet. If he's okay with it, I'll attach the file here asap.

I didn't mean to imply you should share the file here; you could PM or email it if your client is more comfortable with that.

@d12dozr said:

@skyways128 said:

So, I work in meters and export in mm? Got it.

Nope ❗

Import as meters, work in meters, export in meters...do everything with Sketchup using meters. When you open the model in another app for 3D printing, THEN you import as mm and the scale will be correct.

Whoops! 😳 Thanks for the clarification!

Chris and TIG, many thanks for the replies!

As per your advice, I tried up-scaling the model to 1000 times it's actual size, and the empty triangles stopped appearing.

The only leak solid inspector shows now is the open side of the head, which will go away once I mirror the other half of the head and merge them.

Thanks again!

Thanks, Gilles!

That did the trick.