I’m in for true circles as guide circles. This wouldn’t interfere too much with SketchUp’s philosophy with segmented arcs and circles for real geometry, thus keeping the types of basic entities limited for the inferencing engine. (think of extruded segmented circles versus real cylindrical shapes)
If however you can get away with intersecting segmented guide arcs and circles in your workflow, this may be of help:
- draw the desired arcs and/or circles, one at the time.
(- if wanted, use ‘Find Center’ in the right click context menu). - per acr/circle entity right click on it and select ‘Convert to Construction Line’ in the context menu (see *).
‘Convert to Construction Line’ could even be assigned to a new shortcut key to speed up the process. (Edit/Item/Conver to Construction Line > to key)
Now all intersecting guide ‘circles’ and arcs’ will also be deleted as easily as straight guides.
(*) ‘Convert to Construction Lines’ should be downloaded as a plugin to see the command in the context menu.