Transformation Matrix

[garnero]

Cattura.JPG (31.57 KiB) Viewed 1614 times

I'm sorry, I tried to look in this blog but I can't find the solution, ... can you help me?

I'm rotating LAS files and I can't understand where the rotation takes place.
To understand it, I built the rotation matrix with a rotation of 30° with respect to the Y axis and I find the situation that I enclose: where the rotation take place?
Can I choose and modify it in any way?

This is the Matrix, in Attach the result
0.866025 0 -0.5 0
0 1 0 0
0.5 0 0.866025 0
0 0 0 1

THANK YOU

Gabriele

[daniel]

The rotation is always about (0, 0, 0) by default.

The transformation is composed of a rotation and a translation (P' = R.P + T). So you can theoretically 'recenter' the cloud at the end of the process.

However, this can be hard to guess, so you can do this in 3 steps:
1) translate the cloud so that its center is in (0, 0, 0)
2) rotate the cloud
3) apply the inverse translation (1)