EntitiesObserver Weirdness

kwalkerman

OK. I have repeatable steps for the Sketchup:EntitiesObserver that show some STRANGE behavior.

Use this code:

` class KW_EntitiesObserver_Weirdness < Sketchup::EntitiesObserver
def initialize(*args)
super
@m = nil
end
def onActiveSectionPlaneChanged(entities)
end
def onElementAdded(entities,entity)
end
def onElementModified(entities,entity)
puts "onElementModified: #{entity}"
if entity.is_a? Sketchup::Material
@m = entity
end
puts "material is #{@m}"
end
def onElementRemoved(entities,entity)
end
def onEraseEntities(entities)
end

def method_missing(meth,*args,&block)
end

end`

Materials Weirdness:

In Sketchup, draw a few faces. Enclose them in a group
Load the code above
Select the group
Do the following in the ruby console:

s = Sketchup.active_model.selection s[0].entities.add_observer KW_EntitiesObserver_Weirdness.new

Now change the material of one of the faces in the group. The observer will fire (at least) twice. In my case it sometimes fires three times - the first two times for the material. The console output should look like this:

onElementModified: #<Sketchup::Material:0x9c2328> material is #<Sketchup::Material:0x9c2328> onElementModified: #<Sketchup::Face:0xa77588> material is

For some reason, the material that was stored as @m after the first observer call has been lost. Even more strange, if you add the observer, to Sketchup.active_model.entities everything works fine. The steps for this are:

In Sketchup, draw a few faces.
Load the code above
In the ruby console:

Sketchup.active_model.entities.add_observer KW_EntitiesObserver_Weirdness.new

Now change the material of one of the faces in the group. Again, the observer fires (at least) twice. In my case it sometimes fires three times - the first two times for the material. In any case @m maintains the reference to the material:

onElementModified: #<Sketchup::Material:0x98b3c8> material is #<Sketchup::Material:0x98b3c8> onElementModified: #<Sketchup::Material:0x98ae28> material is #<Sketchup::Material:0x98ae28> onElementModified: #<Sketchup::Face:0x98b680> material is #<Sketchup::Material:0x98ae28>

Dan Rathbun

What happens if you hold a reference to your observer instance?

kwalkerman

Hi Dan,

Holding a reference does't make any difference. The only time the reference held by @m is actually stored is when the observer is assigned to Sketchup.active_model.entities.

Also, I noticed that in cases where I have a new file, and I first add the observer to a group's entities collection, the observer does not alert onElementModified for the material. It only alerts for the face.

Thanks,

--
Karen