I'm using Autodesk Inventor, and the perspective drawings look great. However, upon closer inspection, some lines aren't perfectly touching, likely because the part curves and a solid line would be faux.

How picky is the patent office? When zoomed out and printed, this is barely perceptible. My school hand-drafting teacher would have a conniption fit. From experience, would the patent office prefer I try to fake these missing lines with free-drawing?

Drawing lines do not completely touch

  • I’d just clean things up manually. You’ll probably be adding annotations any ways.
    – Eric S
    Sep 30, 2022 at 15:47
  • Also, if Inventor is giving you gaps, you probably have problems with the actual model.
    – Eric S
    Sep 30, 2022 at 18:27
  • @EricS Will do, and thanks.
    – Drakes
    Sep 30, 2022 at 19:48
  • @EricS Yes, gaps make sense when a part cuts into another part. In this case the gaps are on curved/beveled parts that are all by themselves. I suspect the profile of the curves are not being fully drawn because they are not true edges.
    – Drakes
    Sep 30, 2022 at 19:59
  • @Drakes that should be indicated by diagonal lines even if this may work for everyday purposes to convey the idea. Also do mean literally free hand drawing, why would you not use a function that extends the actual curve? Oct 3, 2022 at 3:46

1 Answer 1


This looks like it represents your indented drawing close enough that if you get a notice to fix it you can just fix it.

These are the USPTO drawings rules for national applications. The drawing rules for PCT applications are more strict.

A popular book is How to Make Patent Drawings: Save Thousands of Dollars and Do It With a Camera and Computer

A more straightforward patent drawing book

How to Make Patent Drawings: A Patent It Yourself Companion

  • 1
    this is funny, I think this is exactly what I used to be doing unaware of this book — I presume the idea is that one takes a photo, convert it to black & white, increase contrast than generates a vector graphic drawing from which some minimal touch-ups and one has demonstrative drawings, or figures. Oct 3, 2022 at 3:48
  • “artistically and competently executed” - I’m going to ready that gem of a phrase next time I need to give polite feedback.
    – Drakes
    Oct 3, 2022 at 7:36

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