Interpreting the transformation matrix and axis tab

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TinaTina
Posts: 1
Joined: Thu Jul 20, 2017 6:15 am

Interpreting the transformation matrix and axis tab

Post by TinaTina »

I aligned 2 set points clouds export from AutoCAD (UCS &WCS), they are pair control points.
After I aligned the two clouds by these pair picking pair points, I got a transformation matrix form the properties tab.

0.13709860 0.99055743 0.00005005 -8.10097122
-0.99055731 0.13709860 -0.00047631 31.27651978
-0.00047867 0.00001573 0.99999988 -1.70254374
0.00000000 0.00000000 0.00000000 1.00000000

What does these value mean?
How can I extract Euler angles from transformation matrix? A rotation matrix from Euler angles is formed by combining rotations around the x-, y-, and z-axes. So the cloud compare transformation matrix is in X-,Y-,Z-axes rotation order?
A process by Mike Day: https://d3cw3dd2w32x2b.cloudfront.net/w ... ngles1.pdf
According to this method, I calculated the rotation angles, get the result as attachment:
It's quite different to the second tab result.
Attachments
Transformation matrix from Cloud Compare
Transformation matrix from Cloud Compare
cc.PNG (6.21 KiB) Viewed 2848 times
Result  By  Mike Day Method
Result By Mike Day Method
bb.PNG (7.26 KiB) Viewed 2848 times
What does the Axis/Angle mean?
What does the Axis/Angle mean?
aa.PNG (5.43 KiB) Viewed 2848 times
daniel
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Re: Interpreting the transformation matrix and axis tab

Post by daniel »

You can copy the transformation (either with CTRL+C directly in the Console, or from the 'Transformation history' section of the cloud properties); then paste it in the 'Edit > Apply Transformation' tool. In this tool you can view the transformation under several modes (matrix, rotation axis and angle + translation, or Euler angles).

Also mind that the rotation axis / angle form is not unique.
Daniel, CloudCompare admin
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