Based on this report T41562,
Simple example of the problem:
- Add a Circle
- Enter EditMode
- Select Face Mode
- Select All (AKey)
- Grab (Nothing happens)
If you have a mesh without faces in edit-mode and use face-select for example,
Quite a lot of tools don't work usefully.
(same for edge select-mode on a mesh containing only vertices, but for purpose of discussion - just talking about faces for now).
Lists of tools which fail when edges/vertices are selected but no faces exist.
- Transform Grab/Rotate/Scale does nothing.
- Extrude does nothing.
- Inconsistent de-select-all verts and edges (AKey) - (but border/circle/mouse select dont work).
- ...Likely others exist, off hand these are the ones I can find...
There are some possible solutions.
- Automatically switch out of face mode (when entering edit-mode - doesn't solve problem completely since you can remove all faces while editing)
- Make tools support this configuration (need to check how to support for each tool).
- Make tools report a warning when its not supported (or add support when it makes sense), otherwise - assume users know what they're doing and not attempt to second-guess their actions.
For this design issue, Id like to come to some agreement on a good way to handle this case.
Some things to consider regarding automatic select-mode switching:
- Users may temporarily remove all faces, so changing select-modes automatic for the users could disrupt their workflow.
- Switching modes automatically could break scripts (and generally give unpredictable behavior).
- Checking if the mesh has faces isn't really reliable since you may have hidden faces which is like having no faces from the users POV.