[Interest] Plane rotations

Igor Mironchik igor.mironchik at gmail.com
Wed Apr 5 14:50:54 CEST 2017

```Hi,

05.04.2017 15:13, Sean Harmer пишет:
> Yes, just use the dot product.

You want to say, that QVector3D::dotProduct() will give me an angle?
>
> Sean
>
> On Wednesday 05 April 2017 14:59:48 Igor Mironchik wrote:
>> Hi,
>>
>> I Googled it and found:
>>
>> The cos of angle between vectors is:
>> |(ax*bx + ay*by + az*bz)
>>
>> -------------------------------------------------------- sqrt(ax*ax +
>> ay*ay + az*az) * sqrt(bx*bx + by*by + bz*bz)|
>>
>> 05.04.2017 14:52, Igor Mironchik пишет:
>>> 05.04.2017 14:45, Igor Mironchik пишет:
>>>> Hi,
>>>>
>>>> 05.04.2017 14:29, Paolo Angelelli пишет:
>>>>> Just cross N and M to get the vector around which to rotate.
>>>>>
>>>>> Then use a QQuaternion to set the rotation in the Qt3DCore::QTransform,
>>>>> and construct it with fromAxisAndAngle(const QVector3D &axis, float
>>>>> angle)
>>>> Ok, I can rotate around the right axis. But what angle should I rotate?
>>> This is my question.
>>>
>>>> And how can I calculate new normal to the rotated plane?
>>>
>>> I just need to know what angle should I rotate.
>>>
>>>>> On Wed, 5 Apr 2017 14:18:56 +0300
>>>>>
>>>>> Igor Mironchik <igor.mironchik at gmail.com> wrote:
>>>>>> Hello,
>>>>>>
>>>>>> Let's say I have two vectors - N (normal vector to plane P1) and M
>>>>>> (normal vector to plane P2).
>>>>>>
>>>>>> How to calculate x, y, z axis rotations angles for plane P2 to make
>>>>>> plane P2 parallel to P1?
>>>>>>
>>>>>> How to calculate x, y, z axis rotations angles for plane P2 to
>>>>>> rotate it
>>>>>> around vector N?
>>>>>>
>>>>>> Thank you.
>>>>>>
>>>>>> And what is the measurement of angle in rotationX() of
>>>>>> Qt3DCore::QTransform?
>>>>>>
>>>>>> I need to calculate angles in this units.
>>>>>>
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```