Best way to iterate all nested entities
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Lets say I've got a model full of nested groups/components.
And I want to find all faces with a particular property in that model .
What is a good solution to this problem?
I tried:
entities.each { |ent| if ent.is_a? Sketchup;;ComponentInstance or ent.is_a? Sketchup;;Group #group ent.entities.each { |ent| if ent.is_a? Sketchup;;ComponentInstance or ent.is_a? Sketchup;;Group #nested group ent.entities.each { |ent| if .. end } end } end }
But I don't know how deep I have to dig!!
Other solution I was thinking of: keep exploding everything until everything is free, then get my faces, undo the exploding part
and move on..Any ideas are appreciated,
thnx liquid
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@dan rathbun said:
So it is much more efficient to iterate the model's
DefinitionList
collection, and access the instances through a definitionsinstances
collection.ah... that makes sense!
@dan rathbun said:
It is their definition that has the entities collection. (The group.entities() method is a shortcut that often deceives novices into thinking that the group instance has entities. It actually is a wrapper method for group.parent.entities )
I'll remember that one , thank you!
Liquid
Extra :
@model.definitions.each { |d| if d.group? puts d.instances[0].class #==> Sketchup;;Group end }
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### IF they aren't inside a context other than the model.entities matching_faces=[] Sketchup.active_model.entities.each{|face| next unless face.is_a?(Sketchup;;Face) ### check for compliance with some 'property' and then matching_faces << face if match } ### then find all others... Sketchup.active_model.definitions.each{|defn| defn.entities.each{|face| next unless face.is_a?(Sketchup;;Face) ### check for compliance with some 'property' and then matching_faces << face if match } }
'matching_faces' is now the array containing ALL matching faces in the model and all components...
Useif ! defn.instances[0]
if you want to skip its inclusion because it is 'unused'... -
@tig said:
if ! defn.instances[0]
you might want to skip its inclusion because it is 'unused'...Which would inserted as line 9.5 (above):
next if defn.instances.empty?
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Correct.
We can't of course anticipate exactly what he wants - my method returns ALL matching faces - even those not included in the current model [or other container's entities]...
By including what I/you suggested he can skip unused definitions usingnext
... -
Yup.. he should be on the right track now.
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When iterating the definitions of a model keep in mind that Image entities also has definitions, and you dont really want to mess around with the entities of this special definition. So make sure to test for
definition.image?
.I've detailed SketchUp definitions and instances in this article: http://www.thomthom.net/thoughts/2012/02/definitions-and-instances-in-sketchup/
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Gentlemen,
Thanks! I wrote my code indeed along the lines TIG wrote..
edit:
Thomthom ok I'll do that!, thnx -
TT makes a good point because Images do not have a '.entities' method - unless you create one...
so at the start of the code dealing with definitions use... Sketchup.active_model.definitions.each{|defn| next if defn.image? defn.entities.each{|face|.....
to skip all Images.
Similarlydefn.group?
spots a 'group
', while anything else in thedefinitions
is a 'component
'... -
This method is fine if you are iterating over the entire model. I have situations when I only want to iterate over a selection. There is no definitions method in that case. I've been using recursion to iterate over a list of components/groups in the selection.
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matching_faces=[] Sketchup.active_model.selection.each{|e| if e.is_a?(Sketchup;;Face) ### check for compliance with some 'property' and then matching_faces << e if match elsif e.is_a?(Sketchup;;Group) e.entities.parent.entities.each{|face| next unless face.is_a?(Sketchup;;Face) ### check for compliance with some 'property' and then matching_faces << face if match } elsif e.is_a?(Sketchup;;ComponentInstance) e.parent.entities.each{|face| next unless face.is_a?(Sketchup;;Face) ### check for compliance with some 'property' and then matching_faces << face if match } end }
etc...
You can of course use the matching to do any number of things... that's up to you to decide... -
@david. said:
I've been using recursion ...
The bad news is that recursion is bad in Ruby, and worse in embedded Ruby.
It can cause a stack overflow, which crashes Ruby, and in the case of SketchUp embedded Ruby, will then crash SketchUp.
The good news is that you can write a method to collect the definitions whose instances are present in the selection.
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@dan rathbun said:
@david. said:
I've been using recursion ...
The bad news is that recursion is bad in Ruby, and worse in embedded Ruby.
It can cause a stack overflow, which crashes Ruby, and in the case of SketchUp embedded Ruby, will then crash SketchUp.
The good news is that you can write a method to collect the definitions whose instances are present in the selection.
I posted examples in a separate Code Snippet topic:
[ Code ] (Iterating) Finding Definitions -
In reality,... instances (Group or Component,) do NOT really have entities collections.
It is their
definition
that has theentities
collection. (Thegroup.entities()
method is a shortcut that often deceives novices into thinking that thegroup
instance has entities. It actually is a wrapper method forgroup.entities.parent.entities
)Also a the
Group
class is a special kind ofComponentInstance
class.Both have a parent
ComponentDefinition
So it is much more efficient to iterate the model's
DefinitionList
collection, and access the instances through a definitionsinstances
collection.
EDIT: Fixed second paragraph,
group.entities.parent.entities
wasgroup.parent.entities
in error. -
@dan rathbun said:
@david. said:
I've been using recursion ...
The bad news is that recursion is bad in Ruby, and worse in embedded Ruby.
It can cause a stack overflow, which crashes Ruby, and in the case of SketchUp embedded Ruby, will then crash SketchUp.
The good news is that you can write a method to collect the definitions whose instances are present in the selection.
I use recursion for digging into nested components levels - because the recursion level is not going to max out the call stack unless you have a model that was designed to crash it. Nobody nests geometry that deep.
Recursing when traversing over connected geometry on the other hand will quickly hit the limit of the call stack.
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@tig said:
> elsif e.is_a?(Sketchup;;ComponentInstance) > e.parent.entities.each{|face| > next unless face.is_a?(Sketchup;;Face) > ### check for compliance with some 'property' and then > matching_faces << face if match > } > end > }
One comment: This section of the code for components didn't work for me. It wasn't giving any error messages, it just wasn't making any changed to the components in my model. I changed the second line to e.definition.entities.each .... and that worked.
One question: I'm not processing faces like this example, but edges. I'm modifying another script from TIG to delete all vertical edges in my model. I need it to also recurse into groups and components, so I've combined it with the script here.
So ... the first time I run the script, it deletes all vertical lines that are not within groups/components. From groups/components, however, it leaves one vertical line in each. (This is run on a simple test file that has three cubes, one is ungrouped, one is a group, the last in a component.) If I run the script a second time, it deletes the remaining vertical lines from the groups/components. I'd appreciate if anyone could explain what's going on here, and if there is a way to write the code such that each vertical edge is dealt with in the first go.
Many thanks,
Shannon -
The API's
Entities
collection(s), is/are actually thinly-exposed (to Ruby,) C++ collection(s).You CANNOT safely both iterate such a set AND delete items from the set AT THE SAME TIME.
Doing so creates a "fence post error" in which the iteration reference skips one (or more) items in the set.
This has been covered so many times before. (Here and in other forums.)
Seems every newbie must fall for this boo boo.
Use the standard Ruby
to_a()
orgrep()
method to take a "snapshot" Ruby array copy of API collections.
Then iterate THAT Ruby copy, viz:
entities.grep(Sketchup::Edge).each {|e| e.erase! if is_vertical?(e) }
is_vertical?()
is a hypothetical utility query method within your plugin's class or module.Would be something like:
def is_vertical?(edge) vec = edge.start.position.vector_to(edge.end.position).normalize vec == [0,0,1] || vec == [0,0,-1] end
Note that some of those old examples were written before we knew how very fast the
grep()
method was.
USE it to filter collections when you want only one class of object. It is FAST!
(This method comes from the mixin moduleEnumerable
, which is mixed into many collection classes.) -
When "drilling down" into the entities of component or groups, it is so very much faster to go through the model's
definitions
collection, checking each definition if it'sinstances
collection hassize > 0
, (and possibly if it isimage? == false
,) and if so...... delete from the definitions entities collection, and all instances are changed.
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.grep
is an iterator itself - so no need for.each
:entities.grep(Sketchup::Edge) {|edge| edge.erase! if is_vertical?(edge) }
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Saying that - bulk methods is much faster than individual actions. Use entities.erase_entities when you erase multiple entities - it also avoids the pitfall of erasing the collection you are erasing from.
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