Issue mirror transformation

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Old 11 November 2013   #1
Issue mirror transformation

I never really had any issue mirror rotation until I stumbled onto this:
how to "mirror" those 2 points:

point transform:(matrix3 [-0.0744505,0.102782,-0.991914] [0.900617,-0.420165,-0.111136] [-0.42819,-0.901608,-0.061286] [-41.0417,2.50814,301.575]) name:"LeftPoint"
point transform:(matrix3 [0.110613,0.061457,-0.991962] [0.958345,0.257846,0.122839] [0.263323,-0.964229,-0.030376] [41.0417,2.50804,301.575])name:"Rightoint"


What I'm actually looking for is to mirror the local X axix rotation value

so let's say that point001 is rotated 15 degree on the x axis I need to have the opposite roll value on the other side.

I need to keep the overall same direction (don't flip axis) SHould I just mirror the whole thing and fix the axis back as to how I want them ?
 
Old 11 November 2013   #2
quick and dirty method

tm = $.transform;
     tm[1] *= -1;
     $.transform = tm;


sorry just read the final part of your post but to actually "mirror" you need to flip an axis otherwise your just rotating 180 degrees around the z axis which is not the same ?

$.transform = ((eulerangles 0 0 180)  as matrix3) * $.transform 

or
$.transform = prerotateZ  $.transform 180;

which is the same thing and the same as rotating 180 degrees about the local z axis in the viewport and very similar to the axis flip above but with the additional flipping of the y axis.

Last edited by Klunk : 11 November 2013 at 08:59 PM.
 
Old 11 November 2013   #3
thanks, but those solution doesn't give me the desired result

I managed to get the desired "mirror" effect using this function

fn MirrorRollAxis Source Target = (
	
	pointParent 			= point name:"Point_Parent"
	pointSource 			= point name:"Point_Source"
	pointSource.parent 		= pointParent
	pointSource.transform 	= Source.transform
	pointParent.transform  	= prescale pointParent.transform [-1,1,1]
	pointSource.transform  	= prescale pointSource.transform [1,-1,1]

	target.transform = pointSource.transform
	delete pointParent;delete pointSource
)

But I dont like having to create node just to get the desired result :/
 
Old 11 November 2013   #4
post the scene and say what objects you want to mirror

(please give a file with max version <= 2012)
 
Old 11 November 2013   #5
the situation might vary. it depends on:
# are mirroring objects children of the same parent
# are they originally flipped against each other
# can they be translated (rotated, scale)
# etc.

the math is simple... you have to multiply transform one with mirror matrix.
for x axis in absolute coordinate system it's:

 
 x_mirror_tm = matrix3 [-1,0,0] [0,1,0] [0,0,1] [0,0,0]
 
 delete objects
 p1 = point name:"R point" pos:[10,0,10] rotation:(eulerangles 45 60 70) axistripod:on box:on cross:off wirecolor:green
 p2 = point name:"L point" axistripod:on box:on cross:off wirecolor:yellow
 	
 p2.transform = p1.transform*x_mirror_tm
 

Last edited by denisT : 11 November 2013 at 10:03 PM.
 
Old 11 November 2013   #6
Originally Posted by mrfred:

  point transform:(matrix3 [-0.0744505,0.102782,-0.991914] [0.900617,-0.420165,-0.111136] [-0.42819,-0.901608,-0.061286] [-41.0417,2.50814,301.575]) name:"LeftPoint"
  point transform:(matrix3 [0.110613,0.061457,-0.991962] [0.958345,0.257846,0.122839] [0.263323,-0.964229,-0.030376] [41.0417,2.50804,301.575])name:"Rightoint"
  


I need to keep the overall same direction (don't flip axis)


in your case the method should be modified a little:

x_mirror_tm = matrix3 [-1,0,0] [0,1,0] [0,0,1] [0,0,0]

 delete objects
 
 p3 = point transform:(matrix3 [-0.0744505,0.102782,-0.991914] [0.900617,-0.420165,-0.111136] [-0.42819,-0.901608,-0.061286] [-41.0417,2.50814,30.575]) name:"LeftPoint" wirecolor:red
 p4 = point transform:(matrix3 [0.110613,0.061457,-0.991962] [0.958345,0.257846,0.122839] [0.263323,-0.964229,-0.030376] [41.0417,2.50804,30.575]) name:"Rightoint" wirecolor:blue
 
 p5 = copy p3 transform:(p3.transform*x_mirror_tm) wirecolor:orange
 p5.transform = prescale p5.transform [1,-1,1]
 resetscale p5
 
 
Old 11 November 2013   #7
or ...
x_mirror_tm = matrix3 [-1,0,0] [0,1,0] [0,0,1] [0,0,0]

delete objects

p3 = point transform:(matrix3 [-0.0744505,0.102782,-0.991914] [0.900617,-0.420165,-0.111136] [-0.42819,-0.901608,-0.061286] [-41.0417,2.50814,30.575]) name:"LeftPoint" wirecolor:red
--p4 = point transform:(matrix3 [0.110613,0.061457,-0.991962] [0.958345,0.257846,0.122839] [0.263323,-0.964229,-0.030376] [41.0417,2.50804,30.575]) name:"Rightoint" wirecolor:blue

p5 = copy p3 transform:((prescale p3.transform [1,-1,1])*x_mirror_tm) wirecolor:orange
 
Old 11 November 2013   #8
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