DC instance make unique

jolran

I got it. Stupid missunderstanding.

If comps is an array of entities I add to the group. It's THEM I should explode. Not give the group entities a new name and
try to explode that object.


	if comps
          gp2=ents.add_group(comps)
          comps.each{|e|   # does NOT like gp2.to_a CRASH!
	     next if not e.valid?
		  e.explode if e.class==Sketchup;;ComponentInstance 
	   }

It's funny I always find the solution 1 min after typing it on this forum.

TIG

Never use ents.add_group() with amy objects within the ()... UNLESS ' ents' is the active_entities.
If it's not then you must add objects to the ents AFTER creating the group as an 'empty group ()'...

jolran

Ok, thanks for reminding me. It even say so in the API, groups should not be created that way.
But I don't know how to do otherwise, if not creating some new entities..

So how do I do it in this case. gp2=ents.add_group(). How do I add comps to gp2? comps=gp2.entities will not work will it?

TIG

gp=ents.add_group()

assuming comp1 is a component-instance

comp2=gp.entities.add_instance(comp1.definition, comp.transformation)

comp1.erase! so it's 'moved' into the group.

OR if it's just a definition and you have a transformation called 'tr'...

comp=gp.entities.add_instance(definition, tr)

IF it's s group it's slightly more convoluted to move it into a group that's not in the active_entities...

gp=ents.add_group()
gp2=gp.entities.add_instance(gp1.entities.parent, gp.transformation)
gp1.erase!
gp1=gp2

you have effectively moved gp1 into gp...

jolran

Thank's a lot TIG! This is new to me and very useful. This only work's with 1 object, no? But I might have multiple components in an array. I will investigate..

Strange I haven't picked this up earlier, been reading this forum very much lately. There is so much to learn...

jolran

This did the trick! I mean created multiple instances inside group.

if comps
           gp2=ents.add_group()
		    cents=gp2.entities
             comps.each{|e|
             		 
	         cents.add_instance(e.definition, e.transformation) 
	   }
	        cents.each{|e|  
	        #if e.class==Sketchup;;ComponentInstance #obselete?
	         
            e.explode
	   }
        end

Edited: Aahh heck... Faced with the same problem again. Can only explode 1 instance in the group..
And if I explode the group gp2.explode it crashes. Added the change to the snippets..

jolran

Yeyy! Now I have exploded all instances inside the group. Changed from cents.each to cents.to_a.each

I know about that method. Stupid did not think about doing that earlier...

Main thing here. Working with instances it is important to get them exploded?

Even if I added 2 instances to gp .Exploded 1 of the instances. Then made a group copy like gp1=gp.copy.
I got splats erasing first group called gp.
Now when every entities is exploded, I can remove the original group safely after copying it.

TIG

Stop iterating entities collections that you will be changing during the iteration !
Fix the list with entities.to_a then all is well even when you explode/erase or otherwise change things...

jolran

Yes

Anyway. Now it's possible to collect edges, faces even materials etc. Nice!

Dan Rathbun

@tig said:

If it's a DC whenever you add an instance of it it's already made unique! It's a DC thing.

This is not true in manual mode. Adding another instance from the Components dialog, does just that.
Afterward... editing one of then, edits them all.

So.. NEW Question:

I do not see a dedicated boolean API method to test a Group or ComponentInstance for uniqueness.

I suppose it would be ...
obj.definition.instances==0
for a ComponentInstance

.. and for a Group:
model.definitions.any?{|d| d.group? && d.instances.length==0 && d.instances.include?(obj) }

I wonder if any of us would like a way to always force a definition to clone itself, so that all instances are always unique.
maybe a force_unique attribute?

jolran

@unknownuser said:

I do not see a dedicated boolean API method to test a Group or ComponentInstance for uniqueness.

Interesting reading.

That confuses me how groups work in SU. It feels like they are Component "light", where they logically(in my head) should only be a group of geometry, and not more than that.

I guess uniqueness has an importance when working with nested DC's. Sometimes find them hard to explode.

Dan Rathbun

@jolran said:

That confuses me how groups work in SU.

Sometimes I confuse myself, as well.

@unknownuser said:

](http://code.google.com/apis/sketchup/docs/ourdoc/group.html)":1yyw26bz]Groups in SketchUp are very similar to Components, except that there is no instancing of groups. That means that you always will have one and only one of each of your groups.

Now that's not correct.

Take an empty model. (It helps to purge the "person" component.)
Draw a cube, and group it.
Then select it, and choose "Copy" from the Edit menu.
Then select Paste from the edit menu, and put the copy somewhere.
Do it again, so there are 3 of them.
Then in the console:
d = Sketchup.active_model.definitions d[0]

#Sketchup::ComponentDefinition:0x6227580
d[0].group?
true
puts d[0].instances
#Sketchup::Group:0x62487bc
#Sketchup::Group:0x62487a8
#Sketchup::Group:0x6248794

Of course, they share the same primitives...
g = d[0].instances g[0].entities.to_a == g[1].entities.to_a

true

@jolran said:

It feels like they are Component "light", where they logically (in my head) should only be a group of geometry, and not more than that.

Your on the correct track ....

@unknownuser said:

](http://code.google.com/apis/sketchup/docs/ourdoc/group.html)":1yyw26bz](In the actual implementation, SketchUp keeps track of groups as a special kind of Component that combines properties of definitions and instances, ...

If you compare the method lists, between Group and ComponentInstance, you'll see they have nearly the same methods.
The difference? A Group cannot be saved out to a file (directly) for use in other models, and it's easier to get at a ComponentInstance's definition, because there's an API method for it.

jolran

That's all very interesting, and probably quite important for us new to Sketchup Ruby to understand how groups and components works.

@unknownuser said:

If you compare the method lists, between Group and ComponentInstance, you'll see they have nearly the same methods.
The difference? A Group cannot be saved out to a file (directly) for use in other models, and it's easier to get at a ComponentInstance's definition, because there's an API method for it.

I was wondering about behaviors? I noticed that if you have a face, draw a square on it and 3pl click to select. Then make a group out of that, it will behave like a cutting component onto that face. You can even unglue it if you rightclick.
However there is no "glue_to" method for groups in the API.

Dan Rathbun

@jolran said:

However there is no "glue_to" method for groups in the API.

Right.. and you should not use a Group, for the job of a ComponentInstance.

Groups are best used for temporary editing both manual and in scripting.

By collecting objects together into a Group, you can:

move them from one edit context to another,
protect them from being modified by crossing edges,
apply a tranform to a set of objects all at once (where they move, scale or rotate all together.)

I would say, that when you get a "set" of objects the way you want, and then wish to use that set multiple places in the model, it's best to then convert them into a ComponentInstance. Especially if your going use scripting, to manipulate them, or glue them to faces.