Sketchup is very good for preparing patent drawings. I have used it. The Office did make some complaint (can't remember what it was), but it was easy to remedy. You can see the drawings at US 9,181,924.

@taffgoch said:

There's a limitation to patent illustrations that could be problematic for SketchUp. The sample image that Mike provided demonstrates it well. Do you see it?

Patent illustrations must be line drawings, with no shading. Or more precisely, shading must be depicted using lines or solid-black; no shades of grey. You can see how this is done in Mike's example image.

I suspect that SketchUp can be manipulated into not using shading/shadows, but it looks like those 'shading lines' are going to have to be added 'manually.' Still, SketchUp could take a lot of the workload out of producing an accurate orthographic line drawing for a patent.

I reproduced a patent image (posted here in a discussion last year) that demonstrated SketchUp's ability to depict the proper orthographic view. (Images on the left taken from a patent.) The SketchUp image, on the right, would have to be further cleaned up, to remove the variable shades from the conic surfaces. Otherwise, it's a near-perfect match.
[attachment=0:3n0diwct]<!-- ia0 -->Conics.jpg<!-- ia0 -->[/attachment:3n0diwct]
I'd vote yes - SketchUp can more-than-adequately do the job. Perhaps, even a 'style' could be defined that would automatically take care of most of the shading work.

Regards,
Taff