vertex.select=False does not work, but vertex.select=True does work
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System Information
Win7 64 bits with sp1

Blender Version
Broken: official 2.76b 64 bits

Exact steps for others to reproduce the error
I want to select/deselect some vertices based on some conditions, for example

for the default scene, we enter the EDIT mode and can find that all the 8 vertices of the cube are selected. Then run this script

import bpy
for obj in bpy.data.meshes:
    bpy.ops.object.mode_set(mode="OBJECT")
    for vertex in obj.vertices:
        if vertex.co.x<0:
            vertex.select=False
            print (vertex.select)
    bpy.ops.object.mode_set(mode="EDIT")
    bpy.context.scene.update()

We find that nothing changes, and all 8 vertices are still selected!

now we deselect all vertices by hand( A-key in 3d window), and run this

import bpy
for obj in bpy.data.meshes:
    bpy.ops.object.mode_set(mode="OBJECT")
    for vertex in obj.vertices:
        if vertex.co.x<0:
            vertex.select=True         #Please note this is True, but above code is False
            print (vertex.select)
    bpy.ops.object.mode_set(mode="EDIT")
    bpy.context.scene.update()

we can find 4 vertices are selected now.

We can repeat case 1 and 2 many times as you wish. So I am puzzled, why does Blender operate "vertex.select=True", but omit "vertex.select=False"? For consistency, if one operation is allowed, why not allow another? Or blender should ban 2 operations by make vertex.select is a read-only atributes?

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Lee June (retsyo) created this task.Nov 9 2015, 3:36 AM

Lee June (retsyo) raised the priority of this task from to 90.

Lee June (retsyo) updated the task description. (Show Details)

Lee June (retsyo) added a project: BF Blender.

Lee June (retsyo) edited a custom field.

Lee June (retsyo) added a subscriber: Lee June (retsyo).

It is necessary to perform deselecting of all in EDIT mode before choosing something.
You should choose a necessary thing in OBJECT mode afterwards.
For example, in this way.

import bpy

C = bpy.context

bpy.ops.object.select_all(action='DESELECT')
for ob in bpy.data.objects:
    if ob.type == 'MESH':
        C.scene.objects.active = ob
        bpy.ops.object.mode_set(mode='EDIT')
        bpy.ops.mesh.select_all(action='DESELECT')
        bpy.ops.object.mode_set(mode='OBJECT')
        ob.data.vertices[0].select = True

This is caused by selection flushing on changing modes.

If you remove all edges and faces the examples work as expected.

You can either set the edge and face selection states. or use the BMesh API which has selection flushing functions.

http://www.blender.org/api/blender_python_api_2_76_release/bmesh.types.html#bmesh.types.BMesh.select_flush

closing.

vertex.select=False does not work, but vertex.select=True does workClosed, ArchivedPublicActions

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vertex.select=False does not work, but vertex.select=True does work
Closed, ArchivedPublic
Actions