[Code] Print the transformation matrix

[thomthom]

Hi, I'm trying to print a transformation matrix, I tried the following:

pointdd = Geom::Point3d.new 11,22,33
tdd = Geom::Transformation.new pointdd
a = tdd.to_a
text="-------------------------------------------------------\n"
4.times do |b|
4.times do |e|
if ((e+1)%4==0)
text << a[e*4+b].to_s+"\n"
else
text << a[e*4+b].to_s+" "+" "+" "+" "+" "+" "+" "+" "+" "+" "
end
end
end
text<<"------------------------------------------------------\n"
UI.messagebox( text, MB_MULTILINE)

I wanted to hear suggestions of more elegant ways to do this. (I wrote several times +" " for failure to escrbir several spaces followed here)

thank you for your attention.

[danielbowring]

Code: Select all

def inspect_transformation(t)
    ta = t.to_a
    return (0...4).collect() {|i|
        ta[i*4, 4].join(', ')
    }.join("\n")
end


Code: Select all

>>> point = Geom::Point3d.new 11,22,33
>>> tdd = Geom::Transformation.new pointdd
>>> puts inspect_transformation(tdd)
1.0, 0.0, 0.0, 0.0
0.0, 1.0, 0.0, 0.0
0.0, 0.0, 1.0, 0.0
11.0, 22.0, 33.0, 1.0


Edit: And if you like things to line up:

Code: Select all

def inspect_transformation_adv(t, args={})
    format = "%.#{args[:places] || 3}f"
    ta = t.to_a.map() {|i|
        format%[i]
    }
    maxlength = ta.max() {|i, j| i.length <=> j.length }.length
    ta = ta.map() {|i|
        i.ljust(maxlength)
    }
    return (0...4).collect() {|i|
        ta[i*4, 4].join(args[:separator] || ', ')
    }.join("\n")
end


Code: Select all

>>> point = Geom::Point3d.new 11,22,33
>>> tdd = Geom::Transformation.new pointdd
>>> puts inspect_transformation_adv(tdd)
1.000 , 0.000 , 0.000 , 0.000
0.000 , 1.000 , 0.000 , 0.000
0.000 , 0.000 , 1.000 , 0.000
11.000, 22.000, 33.000, 1.000


Edit: although that's not the orientation you use

[danielbowring]

Here's one in your format, although you should probably use one of the ones above (More info here)

Code: Select all

def inspect_transformation_adv(t, args={})
    format = "%.#{args[:places] || 3}f"
    ta = t.to_a.map() {|i|
        format%[i]
    }
    maxlength = ta.max() {|i, j| i.length <=> j.length }.length
    ta = ta.map() {|i|
        i.ljust(maxlength)
    }
    return (0...4).map() {|i|
        (0...4).map() {|j|
            ta[j*4+i]
        }.join(args[:separator] || ', ')
    }.join("\n")
end

Code: Select all

>>> point = Geom::Point3d.new 11,22,33
>>> tdd = Geom::Transformation.new pointdd
>>> puts inspect_transformation_adv(tdd)
1.000 , 0.000 , 0.000 , 11.000
0.000 , 1.000 , 0.000 , 22.000
0.000 , 0.000 , 1.000 , 33.000
0.000 , 0.000 , 0.000 , 1.000
>>> puts inspect_transformation_adv(t, {:separator => ' '})
1.000  0.000  0.000  11.000
0.000  1.000  0.000  22.000
0.000  0.000  1.000  33.000
0.000  0.000  0.000  1.000


[thomthom]

Is it to visually inspect the matrix of entities, if so you can use this tool: viewtopic.php?t=44859

[Dan Rathbun]

Here's my simple brute force method:

Code: Select all

  def trans_matrix_text( gt )

    return "Not a trnasformation object!" unless gt.is_a?(Geom::Transformation)
   
    a = gt.to_a
   
    w = 3  # width
    a.each{|n| s = n.to_s.size; w = s if s>w }
    l = (w*4)+3
   
    # create a line output format string:
    fmt = "  | %#{w}s %#{w}s %#{w}s %#{w}s |\n"
   
    text = "\n"
   
    text << (32.chr*2)<<151.chr<<151.chr<<(32.chr*l)<<151.chr<<151.chr<<"\n"
    text << fmt % [  a[0].to_s,  a[1].to_s,   a[2].to_s,  a[3].to_s ]
    text << fmt % [  a[4].to_s,  a[5].to_s,   a[6].to_s,  a[7].to_s ]
    text << fmt % [  a[8].to_s,  a[9].to_s,  a[10].to_s, a[11].to_s ]
    text << fmt % [ a[12].to_s, a[13].to_s,  a[14].to_s, a[15].to_s ]
    text << (32.chr*2)<<151.chr<<151.chr<<(32.chr*l)<<151.chr<<151.chr<<"\n"
   
    return text

  end # def

  pt = Geom::Point3d.new( 11,22,33 )
  text = trans_matrix_text( Geom::Transformation.new(pt) )
 
  UI.messagebox( text, MB_MULTILINE, "Tranformation Matrix" )


I have tweaked my system by copying Consolas font to the font used by dialogs, so I have monospaced text output. (It was easier than tweaking the resources in the executable after each update.)

trans_matrix_MB.png

trans_matrix_IO.png

[dacastror]

Thanks for responding, I have helped a lot.

  me a question arises about the transformations. if I need to apply a transformation to an object but not in the principal coordinate axes, but the coordinate axes of a group (rotated) what should I use?

(sorry for my bad English)

[thomthom]

You mean, transform an object around its own axis and not world axis?

[dacastror]

You mean, transform an object around its own axis and not world axis?

yes, exactly

[thomthom]

Create a local transformation and apply with with .transform!( tramsformation ) instead of setting the .transformation matrix manually. Or am I missing something?

[dacastror]

Create a local transformation and apply with with .transform!( tramsformation ) instead of setting the .transformation matrix manually. Or am I missing something?

How to create a local transformation? I would like to see some sample piece of code to guide me

[dacastror]

I wonder if there is any way to know the orientation of a group with respect to the axis of the world

[TIG]

You have the model's axes from X_AXIS etc and ORIGIN.
Then you have group.transformation.axes or group.transformation.xaxis etc... and group.transformation.origin too...
So you can find the relative locations [which are points3ds] and angles between axes [which are vector3ds] - see the methods for those types...

[thomthom]

Create a local transformation and apply with with .transform!( tramsformation ) instead of setting the .transformation matrix manually. Or am I missing something?

How to create a local transformation? I would like to see some sample piece of code to guide me

Code: Select all


point = instance.transformation.origin
vector = instance.transformation.yaxis
rotation = Geom::Transformation.rotation( point, vector, 30.degrees )
instance.transform!( rotation )
 

[dacastror]

thank you very much Thomas and Tig that prompt reply!

I will try to implement your suggestions right now