The edits Revit makes harder than they should be.

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Drag a box to cut conduit, tray, pipe, duct, or lines.

If you've ever had to rip out the middle of a run (split each segment, delete the bits, fix the ends), you know how long that takes. Power Knife does it in one drag. Anything fully inside the box gets deleted, anything crossing the edge gets trimmed, and it doesn't leave fittings behind. Works in Plan, RCP, Elevation, Section, and 3D Orthographic.