[Bf-committers] "correct" edge selection state?

[Ton Roosendaal]

Hi,

The problems in the flushing code are partially because of the slow  
migration from vertex-only to vertex/edge/face selecting. Not all tools  
are edge/face selection aware yet... adding to the confusement. :)

What I tried to achieve with the flush calls, is that (de)selecting  
always gives the desired result for the highest available selection  
mode (first face, then edge, then vertex). The 'lower' selections then  
can become inconsistant yes, but at least the top level then is fully  
controllable.

Tools should try to use the same 'highest selection' convention where  
possible.

-Ton-


On 26 Apr, 2006, at 19:36, Geoffrey Bantle wrote:

>> Seemingly simple question:
>
>> When a mesh edge is selected/deselected with Edge
> Select
>> mode, and the vertices of neighboring edges are
> already
>> selected, should the neighboring edges become
>> selected/deselected also?  Should vertex selection
> state
>> have any impact on the edge selection state?
>
> The answer to this is that 'it depends'. In edge
> exclusive mode, its possible that an edge may have
> only one of its vertices selected (this is a bug). In
> vert+edge or vert+edge+face mode (but not edge+face!),
> if two selected edges share a vertex and one edge is
> deselected then the neighbor edge is also deselected.
>
> Got a headache yet? :)
>
>> Another way to ask: is edge/face selection dependent
>> or independent of vertex selection state?
>
> The short answer is 'yes'. The longer answer is that
> the current state of blenders vert/edge/face selection
> methods is a bit complicated.
>
> Right now in blender when a face is
> deselected/selected with 'EM_select_face' all of its
> vertices and edges are deselected/selected as well.
> Similarly when an edge is deselected/selected with
> 'EM_edge_select'  its vertices are deslected/selected.
>
> Furthermore when the vertices of an edge are selected
> in vertex or multiselect mode the edge becomes
> selected. Also when the vertices or edges of a face
> become selected in either vertex, edge or multi-select
> mode the face and its edges become selected. This is
> handled through the 'EM_select_flush' and
> 'EM_selectmode_flush' functions in editmesh_lib.c.
>
> Unfortunatley the behavior of EM_select_flush and
> EM_selectmode_flush makes multiselect mode 'broken' in
> about a couple dozen ways. One user I spoke to
> summarized the problem very succintly when he said
> 'You can't actually select what you want with
> multi-select mode'. As far as I can tell this problem
> is entirely due to blenders 'flushing' Multi-select
> and flushing behavior should probably be
> reviewed/revised soon.
>
> Ton, can you comment on this?
>
> Cheers,
> Geoff Bantle
>
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------------------------------------------------------------------------ 
--
Ton Roosendaal  Blender Foundation ton at blender.org  
http://www.blender.org