topology mirror does not work with unconnected meshes (eg. Suzanne eyes) #39409

New Issue

Alessandro Padovani · 2014-03-25T12:57:25+01:00

Alessandro Padovani commented

2014-03-25 12:57:25 +01:00

blender 2.70 release

it seems topology mirror has problems handling not connected meshes
for example it doesn't work with Suzanne eyes

it also seems the problem was fixed in 2.67 but now it is back, see
https://developer.blender.org/T35551

steps:

place Suzanne in the scene
turn on x mirror and topology mirror
select one eyes and play around with the geometry

blender 2.70 release it seems topology mirror has problems handling not connected meshes for example it doesn't work with Suzanne eyes it also seems the problem was fixed in 2.67 but now it is back, see https://developer.blender.org/T35551 steps: - place Suzanne in the scene - turn on x mirror and topology mirror - select one eyes and play around with the geometry ![t-mirror.jpg](https://archive.blender.org/developer/F82526/t-mirror.jpg)

Alessandro Padovani commented

2014-03-25 12:57:25 +01:00

Changed status to: 'Open'

Alessandro Padovani commented

2014-03-25 12:57:25 +01:00

Added subscriber: @padone

Campbell Barton was assigned by Sergey Sharybin

2014-03-28 09:15:29 +01:00

Sergey Sharybin commented

2014-03-28 09:15:29 +01:00

Added subscribers: @ideasman42, @Sergey

Sergey Sharybin commented

2014-03-28 09:15:29 +01:00

@ideasman42, you know this area better than anyone else :)

Campbell Barton commented

2014-03-29 07:00:39 +01:00

Changed status from 'Open' to: 'Archived'

Campbell Barton closed this issue

2014-03-29 07:00:39 +01:00

Campbell Barton commented

2014-03-29 07:00:39 +01:00

Topology based mirror relies on unique topology, which isn't the case around Suzanne's eyes.

Closing.

Topology based mirror relies on unique topology, which isn't the case around Suzanne's eyes. Closing.

Alessandro Padovani commented

2014-04-05 09:58:28 +02:00

thank you for your reply Barton,

if this is the case then this limit should be documented, so Blender users could know about it and stop claiming this as a bug. Indeed the official wiki manual takes Susanne as example for the topology mirror, but doesn't mention any limit of this kind. This may be a misleading example especially for new users.

http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Meshes/Editing/Basics/Mirror
" For an example of how to use Topology Mirror open up a new Blender scene, then delete Blender's default cube and add a Monkey Object to the 3D Viewport. "

Also, I wonder if you could fix this limitation and add unconnected meshes support to the topology mirror tool. I don't know how to deal with the Blender code, but conceptually it could be something like this.

REM identify geometry islands (unconnected meshes)
while there is some geometry left
  select one polygon
  select the connected mesh
  mark island and remove geometry from search

REM apply topology mirror to all islands
if topology mirror is active
  for every island
    apply topology mirror

Well the concept is easy, but I don't know if this approach of marking islands could be easily implemented in the actual code. This is another story. Please let me know if you think this idea may be useful.

Bye, Alessandro :)

thank you for your reply Barton, if this is the case then this limit should be documented, so Blender users could know about it and stop claiming this as a bug. Indeed the official wiki manual takes Susanne as example for the topology mirror, but doesn't mention any limit of this kind. This may be a misleading example especially for new users. http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Meshes/Editing/Basics/Mirror " For an example of how to use Topology Mirror open up a new Blender scene, then delete Blender's default cube and add a Monkey Object to the 3D Viewport. " Also, I wonder if you could fix this limitation and add unconnected meshes support to the topology mirror tool. I don't know how to deal with the Blender code, but conceptually it could be something like this. ``` REM identify geometry islands (unconnected meshes) while there is some geometry left select one polygon select the connected mesh mark island and remove geometry from search ``` ``` REM apply topology mirror to all islands if topology mirror is active for every island apply topology mirror ``` Well the concept is easy, but I don't know if this approach of marking islands could be easily implemented in the actual code. This is another story. Please let me know if you think this idea may be useful. Bye, Alessandro :)

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topology mirror does not work with unconnected meshes (eg. Suzanne eyes) #39409