Axes question

Pixero

I'm trying to understand how axes works and have a script where axes are set to a custom value. I create a face and a group and still the origin and axes of the group is the default origin and axes.
Why doesn't it respect the new working axes?
If I do it in the UI it works as expected and I get it to line up with the custom axes set in the script.

I'm looking for a way of not having to transform everything back to origo to get group/component origin and axes correctly as this workflow has caused issues with certain values and rotation directions for me.

I found the Sketchup.active_model.axes.set(origin, xaxis, yaxis, zaxis) and thought it might be possible to:

First, store the current axes.
Set origin and axes to some custom value.
Then do stuff within the new origin and axes. (Like creating a face and group it and have groups and components to have their axis set correct.)
And finally reset axes as they were before the script was executed.

I got really exited about this and was hoping it could be a work around until we get proper set axes for components and groups.

If done in the UI it works so why doesn't it within my script?

Pixero

Here is a small test script that describes what I'm after.
Only that it doesn't align the created groups axis with the set axes.
Any ideas?
Note that for this test I have hard coded some points and vectors.

module JS
  class Axestest

    model=Sketchup.active_model
    entities=model.active_entities


    # First we save the current origin and axes so we can reset back to them when we are done.
    current_origin = Geom;;Point3d.new(model.axes.origin)
    current_xaxis = Geom;;Vector3d.new(model.axes.xaxis)
    current_yaxis = Geom;;Vector3d.new(model.axes.yaxis)
    current_zaxis = Geom;;Vector3d.new(model.axes.zaxis)

    # Debug
    puts current_origin.to_a
    puts current_xaxis.to_a
    puts current_yaxis.to_a
    puts current_xaxis.to_a


    # Now get the point for the temp_origin and temp_axes
    temp_origin = Geom;;Point3d.new(20, 10, 0)
    temp_xaxis = Geom;;Vector3d.new(1, 1, 0)
    temp_yaxis = Geom;;Vector3d.new(-1, 1, 0)
    temp_zaxis = Geom;;Vector3d.new(Z_AXIS)

    # Set the origin and axes to the temp_axes
    model.axes.set(temp_origin, temp_xaxis, temp_yaxis, temp_zaxis)

    # Do stuff here to (hopefully) "set" group/component axes correctly align with the object
    pt0=Geom;;Point3d.new(10, 20, 0)
    pt1=Geom;;Point3d.new(20, 30, 0)
    pt2=Geom;;Point3d.new(20, 10, 0)
    pt3=Geom;;Point3d.new(30, 20, 0)

    group=entities.add_group
    entities=group.entities    
    base=entities.add_face(pt0, pt2, pt3, pt1)


    # At the end reset the axes
    model.axes.set(current_origin, current_xaxis, current_yaxis, current_zaxis)

  end#class
end#module

Pixero

No one?

Pixero

I solved this problem by doing it a bit differently. I set the axes to the temp axes and then create all geometry and groups/components at original "world" origo and then at the end used
tr = Sketchup.active_model.axes.transformation
to transform the component to the temp axes and finally revert axes back to what it was before.

Maybe it's an unorthodox way of doing it but I found that by creating everything at world origo it was much easier to add stuff. And it works well with all components axis set perfectly.

Here is a small test script that shows the process if anyone is interested.

module JS
  class Axestest

    model=Sketchup.active_model
    entities=model.active_entities

    # First we save the current origin and axes so we can reset back to them when we are done.
    current_origin = Geom;;Point3d.new(model.axes.origin)
    current_xaxis = Geom;;Vector3d.new(model.axes.xaxis)
    current_yaxis = Geom;;Vector3d.new(model.axes.yaxis)
    current_zaxis = Geom;;Vector3d.new(model.axes.zaxis)

    # Now get the point for the temp_origin and temp_axes (Hardcoded for this example)
    temp_origin = Geom;;Point3d.new(20, 10, 0)
    temp_xaxis = Geom;;Vector3d.new(1, 1, 0)
    temp_yaxis = Geom;;Vector3d.new(-1, 1, 0)
    temp_zaxis = Geom;;Vector3d.new(Z_AXIS)

    # Set the origin and axes to the temp_axes
    model.axes.set(temp_origin, temp_xaxis, temp_yaxis, temp_zaxis)
	
	# Point for a rectangle.
    points = [
      Geom;;Point3d.new( 0,  0, 0),
      Geom;;Point3d.new(10,  0, 0),
      Geom;;Point3d.new(10, 20, 0),
      Geom;;Point3d.new( 0, 20, 0)
    ]	
  
    group=entities.add_group
    entities=group.entities   
    base=entities.add_face(points)	

    tr = Sketchup.active_model.axes.transformation
	
	# Transform the group/component so that it is local to the temp axes. 
    group.transform!(tr)

    # At the end reset the axes
    model.axes.set(current_origin, current_xaxis, current_yaxis, current_zaxis)

  end#class
end#module

Dan Rathbun

You might have missed the fact that the virtual helper classes Point3d, Vector3d and Array, can be transformed.

So if you were not creating a group, you could do before actually creating the geometry:
points.map! {|pt| pt.transform!(tr) }

For a group, you can actually apply the transform to the group, before adding the geometry. (You might need to assign a temporary cpoint to prevent SketchUp from garbage collecting it, as is normal.)
This will prevent the users from seeing geometry appear in a strange place.

Dan Rathbun

@pixero said:

I'm trying to understand how axes works and have a script where axes are set to a custom value. I create a face and a group and still the origin and axes of the group is the default origin and axes.

Why doesn't it respect the new working axes?

Only the native tools respect the custom Axes setting by default.

If they had suddenly changed the API so that ALL code creating geometry in model space used the custom axes, they'd have broken a multitude of extensions, causing havoc.

Another facet, is that the original model origin and axes actually remain unchanged.

So, anyway, they decided that coders themselves had to decide to honor the user's custom axes settings.

Dan Rathbun

Add coming from all this would be the need to detect when the user changes the axes:

# encoding; UTF-8
#
# A simple Axes Observer to detect when a user changes axes.

module Author
  class AxesSpy < Sketchup;;EntityObserver
    
    @@instance ||= self;;new

    def self;;attach( mod = Sketchup.active_model )
      mod.axes.add_observer(@@instance)
    end

    def onNewModel(mod)
      self;;attach(mod)
    end
    alias_method ;onOpenModel, ;onNewModel

    def expectsStartupModelNotifications()
      true
    end

    def onChangeEntity(ent)
      puts "AxesSpy; #{ent.inspect} changed."
    end

    Sketchup.add_observer(@@instance)

  end
end

Note that the Axes object was first exposed with SketchUp 2016.

Edit: Fixed alias_method call. args were swapped, in error.
(I always seem to get them backwards. I always think "alias this as that", but it is more like "newalias that of this".)

Pixero

Thanks for the info.