the knife displays the size measure
The knife displays the size "Measure settings"
In blender, there is no way to find out the diameter or radius of an object made by other images and not from a primitive.
This would be a convenient addition to the "Knife" tool.
1 Comment
Now you need to press S key to have measure option (length and angle) with knife tool. Is it really needed to have measure value displayed all the time? Just asking. If it will be optional (to turn off in preferences - no problem with that). If not - it will clutter the view - especially with small objects, imo.