Component axis problem

Pixero

Not sure why I'm having such a hard time getting this right but following TIGs guide, the Components BoundingBox/selection box remains unrotated until I open the component to edit. After exiting out of the edit component mode, the selection box is properly rotated, even though I still have some work left to get the component axis where I want it... Coding can be sooo frustrating...

XorUnison

@pixero said:

Not sure why I'm having such a hard time getting this right but following TIGs guide, the Components BoundingBox/selection box remains unrotated until I open the component to edit. After exiting out of the edit component mode, the selection box is properly rotated, even though I still have some work left to get the component axis where I want it... Coding can be sooo frustrating...

That's what I thought during my first month or so, but eventually it gets a lot easier as you learn how Sketchup and Ruby work.

I don't know that phenomenon personally but I think it might be related to the component not being refreshed properly. You could try to redraw it:

   dcs = $dc_observers.get_latest_class
   dcs.redraw(entity,progress_bar_visible=false,is_recursive_call=false)

TIG

Sorry, I rushed out the code snippets...
You also need to do a compdef.invalidate_bounds
after the changes, inside the model.start_operation...commit block, to make it change visually !
http://www.sketchup.com/intl/en/developer/docs/ourdoc/componentdefinition#invalidate_bounds

Pixero

Now I got the rotation of the boundingbox working as it should.
However the transformation of the components axis is still at origo.
Rotated correctly but not transformed.
I must still be missing something?


tr = comp.transformation
rotvector = pt1-pt0
originvector = Geom;;Vector3d.new(1,0,0)
angle = rotvector.angle_between originvector
wfc.transform!(tr.inverse)	
	
tr2 = Geom;;Transformation.rotation(ORIGIN, Z_AXIS, angle) 
comp.transform!(tr2)
	
compdef.entities.transform_entities(tr2.inverse, compdef.entities.to_a)
compdef.invalidate_bounds
comp.transform!(tr)

sdmitch

@pixero said:

Now I got the rotation of the boundingbox working as it should.
However the transformation of the components axis is still at origo.
Rotated correctly but not transformed.
I must still be missing something?


> tr = comp.transformation
> rotvector = pt1-pt0
> originvector = Geom;;Vector3d.new(1,0,0)
> angle = rotvector.angle_between originvector
> wfc.transform!(tr.inverse)	
> 	
> tr2 = Geom;;Transformation.rotation(ORIGIN, Z_AXIS, angle) 
> comp.transform!(tr2)
> 	
> compdef.entities.transform_entities(tr2.inverse, compdef.entities.to_a)
> compdef.invalidate_bounds
> comp.transform!(tr)	
>

Did you ever get this figured out?

Here is what I came up with.

mod = Sketchup.active_model
ent = mod.active_entities
sel = mod.selection
grp = ent.first; #<--For test purposes
cmp = grp.to_component
cd = cmp.definition; cde = cd.entities; ct = cmp.transformation
cmp.transform! ct.inverse
org = cmp.bounds.corner(0)
#rotvector = pt1-pt0
#originvector = Geom;;Vector3d.new(1,0,0)
#angle = rotvector.angle_between originvector
#angle = -angle * (rotvector.y<=>0)
angle = -30.degrees #<--For test purposes
tr0 = Geom;;Transformation.rotation(org,Z_AXIS,angle)
cde.transform_entities(tr0,cde.to_a)
bb = Geom;;BoundingBox.new()
cde.each{|e| bb.add e.bounds}
org = bb.center
tr1 = Geom;;Transformation.new(org)
cde.transform_entities(tr1.inverse,cde.to_a)
cmp.transformation = cmp.transformation * tr1
cmp.transform! ct * tr0.inverse
cd.invalidate_bounds

Pixero

Yes I figured it out. Thanks anyway.

Pixero

I have found a bug in my script that causes errors when drawn at certain angles.
When less than 90 degrees the angle needs to be negative and that works well with this fix but when it is 90 degrees or -90 degrees I cant seem to find a way of getting it correct without overwriting the values. Any clues how to do this?

def set_origin(compdef, compinst, pt0, pt1, pt3)
	tr1 = compinst.transformation
	rotvector = pt1-pt0
	originvector = Geom;;Vector3d.new(1,0,0)
	org = pt3
	angle = rotvector.angle_between originvector
	
	if angle < 90.degrees
		angle2 = -angle
	elsif angle > 90.degrees
		angle2 = angle	
	end #if
	
        # This part don't trigger when it's not exactly 90 degrees. 
        # If its just below or above but not enought to be caught in the <90 or >90. 
        # 90.00000000000007 doesn't trigger it. (1.570796326794898 in radians)

	if angle == 90.degrees  
		angle2 = -90.degrees
		puts "I'm 90"		
	elsif angle == -90.degrees 
		angle2 = 90.degrees
		puts "I'm -90"
	end

	compinst.transform! tr1.inverse	
	tr2 = Geom;;Transformation.rotation(org, Z_AXIS, angle2) 
	tr3 = Geom;;Transformation.new(org)	
	compdef.entities.transform_entities(tr2, compdef.entities.to_a)		
	compdef.entities.transform_entities(tr3.inverse, compdef.entities.to_a)	
	compinst.transformation = compinst.transformation * tr3
	compinst.transform! tr1 * tr2.inverse
	compdef.invalidate_bounds
end #def

sdmitch

Replace 90.degrees with Math::PI/2.

Pixero

Thanks, I tried that but the result is the same.
Is there a way of clamping very small values since 90.00000000000003 degrees seem to be enough not to work?


	if angle == Math;;PI/2       
		angle2 = -90.degrees		
	elsif angle == -(Math;;PI/2) 
		angle2 = 90.degrees
	end

slbaumgartner

This issue is unavoidable with finite precision math on the computer. You have to choose a threshold of significance and then test for agreement within that tolerance, e.g.

if (angle.degrees - 90.0).abs < threshold

Of course, then you will become subject to all the same complaints as SketchUp gets for its internal 0.001 inch tolerance for consolidating Vertices - which is due to exactly the same situation!

sdmitch

I don't think the angle between vectors is ever going to be negative. Since you are measuring the angle from the x axis, you will need to use the y value of the rotvector to determine if the angle is negative or positive.

angle *= -(rotvector.y<=>0)

In a Sketchup rotation transformation, a positive angle is a counter clockwise rotation.

Pixero

I think I finally solved it by checking which of the pt0.y and pt1.y is larger and treat it different accordingly. Seems to work now.
Thanks for you input.

Pixero

I just thought I'd post this snippet in case it will help someone with a similar problem.

def set_origin(compdef, compinst, pt0, pt1, pt3)
	tr1 = compinst.transformation
	rotvector = pt1-pt0 
	originvector = Geom;;Vector3d.new(1,0,0)
	org = pt3
	angle = rotvector.angle_between originvector	
	
	if angle < 90.degrees 
		angle2 = -angle
	elsif angle > 90.degrees
		angle2 = angle	
	end #if

	if angle == Math;;PI/2 
		angle2 = -90.degrees 
	end
	
	if pt0.y > pt1.y && angle == Math;;PI/2 #Check if it's drawn at 90 degrees but in opposite direction
		angle2 = 90.degrees 
	end
	
	compinst.transform! tr1.inverse	
	tr2 = Geom;;Transformation.rotation(org, Z_AXIS, angle2) 
	tr3 = Geom;;Transformation.new(org)	
	compdef.entities.transform_entities(tr2, compdef.entities.to_a)		
	compdef.entities.transform_entities(tr3.inverse, compdef.entities.to_a)	
	compinst.transformation = compinst.transformation * tr3
	compinst.transform! tr1 * tr2.inverse
	compdef.invalidate_bounds

end #def