3D cutting planes do it nicely, but I need it for 2D documentation.
3D views are a really valuable aspect of documentation created with AC...so don't be afraid to use them, even if they are (unfortunately) unlinked once annotated.
With the 3D window view that you want - which I presume is a top-down axo view, internal engine, hidden line mode and appropriate cutting plane:
Select the marquee tool, then select the 'flat marquee' method (simple rectangle).
Marquee the view, issue Copy command/shortcut: you'll get a dialog asking if you want a scaled image, etc...
Open an independent Worksheet (AC11) or Detail (AC9 or 10) and Paste the content there. It should be to scale. Annotate as desired. Just have to make a note to yourself to remember to copy/paste again if the model changes since this is not 'live'.
Same process works nicely for axo views that correspond to building sections - to provide a useful small 3D 'key' drawing adjacent to sections in your document set that helps clients and builders really understand where the section cut is...
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AC 26 USA and earlier • macOS Ventura 13.4, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB