Group moves to origin when I doubleclick to select component

Dan Rathbun

It happens because when you are in the group's edit context, you are within the group's co-ordinate system. So the SketchUp interface shows you the axis anchored on the group's origin.

BUT... the world origin remains unchanged.

Dan Rathbun

See group.transformation.origin
and the Geom::Transformation class, in the online docs.

bobdiya

Dan, Thank you for your reply.

Origin of the group g.transformation.origin is (150, 10, 3). One of the corners' (say P) coordinate of RectangleBox is (19, 0, 0). (RectangleBox is ComponentInstance and belongs to the group.

Seeing the value (19,0,0) and the position of the point P, it is clear the coordinate is with respect to the Group's coordinate system. So I need to add the group's origin to get the coordinates of P in Sketchup coordinate system. That would be - (169, 10, 3).

Question: This looks like the hard way. Is there any direct way?

Let me give you the actual picture.
Problem I am trying to solve: Find all the faces that are touching (in contact with) other faces in the selection.

The approach

I get all the plys (RectangleBoxes i.e., ComponentInstances) in the selection (Recursive solution).
Then I get all the faces of the plys
I go on to compare each face against every other face to see if they are in contact. If they are then I add it to the resulting array.

**Another query:**In get_extremes_of_face method face.vertices returns vertices with respect to the Group's origin. And this is where i will need to offset the origin of the group to get the 'absolute coordinates'. But is there a better way to do this?

      def get_all_faces(ply)
        entities = ply.definition.entities
        all_faces = []
        for entity in entities
          if entity.instance_of?(Sketchup;;Face)
            all_faces << entity
          end
        end
        return all_faces
      end
      
      def is_face_coplanar_to_another?(face1, face2)
        face1_extremes = get_extremes_of_face(face1)
        face2_extremes = get_extremes_of_face(face2)
        if(face1.area > face2.area)
          val = check_if_one_extremes_contain_another(face1_extremes, face2_extremes)
        else
          val = check_if_one_extremes_contain_another(face2_extremes, face1_extremes)
        end

        return val
      end

      def get_extremes_of_face(face)
        vertices = face.vertices
        i = 0
        array = []
        x_value1 = []
        y_value1 = []
        z_value1 = []
        for ii in (0..3)
           array[i] = vertices[ii].position
           x_value1[i] = array[i][0]
           y_value1[i] = array[i][1]
           z_value1[i] = array[i][2]
           i += 1
        end
        x_min = x_value1.min
        x_max = x_value1.max
        y_min = y_value1.min 
        y_max = y_value1.max 
        z_min = z_value1.min 
        z_max = z_value1.max
        value = {;x_min => x_min,;x_max => x_max,;y_min => y_min,;y_max => y_max,;z_min => z_min,;z_max => z_max}
        return value
      end

      def check_if_one_extremes_contain_another(ex1, ex2)
        if (ex1[;x_min] <= ex2[;x_min] && ex1[;y_min] <= ex2[;y_min] && ex1[;z_min] <= ex2[;z_min])
          if(ex2[;x_max] <= ex1[;x_max] && ex2[;y_max] <= ex1[;y_max] && ex2[;z_max] <= ex1[;z_max])
            return true
          else
            return false
          end
        end
        return false
      end

Dan Rathbun

OK some basic Ruby. Most Ruby collection classes have the Enumerable mixin module included within them.

You can always check via the ancestors() method (which will list mixed in modules, at the point in the class hierarchy when they were mixed in.)
Sketchup::Entities.ancestors %(#004040)[>> [Sketchup::Entities, Enumerable, Object, JSON::Ext::Generator::GeneratorMethods::Object, Kernel, BasicObject]]
(Notice also that module Kernel is mixed into every Ruby class, by it being mixed into Object.)

So, use the grep() method from module Enumerable, because it is very fast.
It can replace this entire method:


def get_all_faces(ply)
  entities = ply.definition.entities
  all_faces = []
  for entity in entities
    if entity.instance_of?(Sketchup;;Face)
      all_faces << entity
    end
  end
  return all_faces
end

with:
all_faces = obj.entities.grep(Sketchup::Face)

If grep() does not find any objects of that class, or it's subclasses, then it returns an empty array.

But, grep() also has an optional block form, in which the result array is passed into a block if supplied:

all_faces = obj.entities.grep(Sketchup;;Face) {|faces|
  faces.each {|face|
    # check something about each face here
  }
}

Dan Rathbun

@bobdiya said:

Seeing the value (19,0,0) and the position of the point P, it is clear the coordinate is with respect to the Group's coordinate system. So I need to add the group's origin to get the coordinates of P in Sketchup coordinate system. That would be - (169, 10, 3).

Question: This looks like the hard way. Is there any direct way?

Nope. (It is something coders have asked for forever, but has not been added to the API.)

So coders need to apply each nested level's transformation to get the world co-ordinate:

worldcoord = inst.transformation.origin.transform(grp.transformation)

Dan Rathbun

@bobdiya said:

The approach

I get all the plys (RectangleBoxes i.e., ComponentInstances) in the selection (Recursive solution).

Then I get all the faces of the plys

I go on to compare each face against every other face to see if they are in contact. If they are then I add it to the resulting array.

Component Instances do not "have" faces, because they do not "have" entities collections.

It is the Component Definition that has the entities collection.

ALL instances of THAT definition shares the entities. Edit one of the instances, and you edit them ALL.

So you need only get the faces once, and hence the relative vertices once.

Dan Rathbun

I would think it faster to use Face.classify_point() to check if vertices of one face, lie upon another face.

tt_su

@dan rathbun said:

@bobdiya said:

Seeing the value (19,0,0) and the position of the point P, it is clear the coordinate is with respect to the Group's coordinate system. So I need to add the group's origin to get the coordinates of P in Sketchup coordinate system. That would be - (169, 10, 3).

Question: This looks like the hard way. Is there any direct way?

Nope. (It is something coders have asked for forever, but has not been added to the API.)

Given a single vertex you cannot return a world coordinate since it could belong to an Entities collection that might appear several places in the model.
You need to have the combined transformation of the specific path you want the world coordinate for. I don't see what type of method would improve over what one already do (collecting the nested transformation.) Suggestions are welcome.

Dan Rathbun

@tt_su said:

You need to have the combined transformation of the specific path you want the world coordinate for. I don't see what type of method would improve over what one already do (collecting the nested transformation.) Suggestions are welcome.

You know that is exactly what we'd like.

We would like the heavy work done on the C-side, so it is fast, and we only need call a single method.

tt_su

Like an optional argument in Vertex.position perhaps - that takes a transformation argument?

tt_su

Also, do anyone have a test script where current solution is slow?

Dan Rathbun

@tt_su said:

Like an optional argument in Vertex.position perhaps - that takes a transformation argument?
Brainstormin'

Umm. I was thinking more of a .world_position() instance method for Group and ComponentInstance classes.
But this may not be the most helpful.

Maybe think more of working in "Local" and "World" modes.
And we gave a block form world and (maybe) local methods.
(Sort of the old "with this do that" construct.)

component_instance.world {|inst|
  # any vertice, point3d, vector3d, etc.,
  #  accessed within block is in world co-ordinates
}

?

slbaumgartner

@dan rathbun said:

@tt_su said:

Like an optional argument in Vertex.position perhaps - that takes a transformation argument?
Brainstormin'

Umm. I was thinking more of a .world_position() instance method for Group and ComponentInstance classes.
But this may not be the most helpful.

Maybe think more of working in "Local" and "World" modes.
And we gave a block form world and (maybe) local methods.
(Sort of the old "with this do that" construct.)

component_instance.world {|inst|
>   # any vertice, point3d, vector3d, etc.,
>   #  accessed within block is in world co-ordinates
> }

?

Seems to me that to avoid complete chaos for Components, it would need to be necessary either to make any "world" version of the Component read-only or else to intercept all of the setter methods on Entities and apply the reverse transformation back to the ComponentDefinition's "local" coordinates. Otherwise, any modifications made to the "world" version within the code block would create a mess in the ComponentDefinition! This seems like a terrible amount of complexity and risk of bugs!

Here's a different idea: what if there was a "export_to_world" method on ComponentInstance that would create a new Group containing copies of the ComponentDefinition's Entities transformed into "world" coordinates per that ComponentInstance's Transformation(s)? Because the copy's Entities would no longer be shared with the ComponentDefinition, there would be no risk of messing it up. Alterations made to the Group would not affect the ComponentDefinition or any of its ComponentInstances.

Steve

Dan Rathbun

Steve, my original idea is morphing into something overly complicated.

I never wanted to imply a "world edition" of any Group or ComponentInstance instance object.

I really meant that the origin (which is actually a property of a transformation object,) be returned in world co-ordinates instead of local co-ordinates. (So the instance object is not changed.)

But this only within some scope mechanism. (A method block is only one such example.)

Copying an instance into the world model entities, is easy enough now.

I did not intend something that modified the model directly. I was aimed at simplifying virtual calculations.

Dan Rathbun

@dan rathbun said:

@tt_su said:

Like an optional argument in Vertex.position perhaps - that takes a transformation argument?

Umm. I was thinking more of a .world_position() instance method for Group and ComponentInstance classes.

Oh.. sorry (brain fart)

Yes the position() method is on the Vertex class, so the proposed world_position(), would also have to be upon this class.
I do not known what would be better, a new method, or adding an optional :world symbol (or "world" string,) argument. (I DO know I hate positional boolean args, so I'd rather not see a default false arg, that we need to pass true in order to get world co-ordinates.)

Above, where I ponder about a scope (or method block,) ... creating any of the "virtual" dimension classes (in module Geom,) would return new object using world co-ordinates,. instead of local co-ordinates.

So in such a block edge.start.postion (for an edge that was nested at some level,) would return a new Geom::Point3d instance, but it's x, y, z would be set to world co-ordinates.

slbaumgartner

@dan rathbun said:

Steve, my original idea is morphing into something overly complicated.

I never wanted to imply a "world edition" of any Group or ComponentInstance instance object.

I really meant that the origin (which is actually a property of a transformation object,) be returned in world co-ordinates instead of local co-ordinates. (So the instance object is not changed.)

But this only within some scope mechanism. (A method block is only one such example.)

Copying an instance into the world model entities, is easy enough now.

I did not intend something that modified the model directly. I was aimed at simplifying virtual calculations.

So I guess I miss the point of the code block you suggested...what would it be iterating over?

Dan Rathbun

There is NO rule that states that code blocks must be iterative!

For example, normal begin ... end or do ... end code blocks are not themselves iterative. Nor are def ... end code blocks iterative.

A block of code is a scope mechanism. It can be iterated by calling it multiple times from an iterative expression such as for. Or a method block, can contain a for expression that calls a passed code block using a yield expression.

What I am proposing is most like the new Ruby 2.0 using keyword, and the refinement construct. In fact I said that above, where I called it a "with this do that" concept.

tt_su

@dan rathbun said:

Yes the position() method is on the Vertex class, so the proposed world_position(), would also have to be upon this class.

But you cannot return a single world position for a vertex unless you have some extra info. If the vertex belong to a definition with multiple instances there are multiple possible world positions.

And there was some mention of performance concern - did anyone have a sample script of this?

Dan Rathbun

@tt_su said:

But you cannot return a single world position for a vertex unless you have some extra info.

RIGHT.. I gotcha'

We would need to let Ruby know the parent instance's transform. (Not automatic unless in user edit mode.)

I guess we can do this now. We just create a copy of the instance's transformation, call it **t**:
world_pt = edge.start.position.transform(t)
I guess I was pondering how to automatically call #transform(t) upon all newly created Geom::Point3d instances, within a code block scope.

So, yes I suppose an optional "tranform" class argument for Vertex#position would be handy. (It could be a Geom::Transformation instance, a Geom::Vector3d in world context, OR either an Array or Geom::Point3d offset from ORIGIN.) So it could look like:
world_pt = edge.start.position(t)

(2) So lets say you have collected a series of vertices (in an array verts.) And you want their world co-ordinates:
world_pts = verts.map {|v| v.postion(t) }

We have to use map, because the API's Array#tranform() and Array#tranform!() methods, refuse to apply a transform to an array with anything other than than 3 numerics.
Even though each individual element has a transform method.

Example, you have an array of Geom::Point3d objects, and you want to transform ALL elements the same.
The Array class transform methods should do this IF the the elements are not numeric, and they respond_to?(:transform). (Add: Any element that does not "respond_to" is returned unchanged.))