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# how to Rotate Model

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Hi every one ...

i want to rotate my 3dmodel in roll-pitch-yaw axis

i have just axis(x,y,z) vector and up(x,y,z) vector

so how to rotate my model by axis(x,y,z) vector + up(x,y,z) vector values?

 D3DXVECTOR3 * axis=new D3DXVECTOR3; axis->x = -0.14; axis->y = -0.99; axis->z = -0.04; D3DXVECTOR3 * up=new D3DXVECTOR3; up->x = -0.99; up->y = 0.14; up->z = 0.07; D3DXMATRIXA16 mWorld; /////////////////////////////////////////////////////////////////// D3DXMatrixLookAtLH(&mWorld,g_Camera.GetEyePt(),axis,up); //////////////////////////////////////////////////////////////////// mWorld *= *g_Camera.GetWorldMatrix(); D3DXMATRIXA16 mProj; mProj = *g_Camera.GetProjMatrix(); D3DXMATRIXA16 mView; mView = *g_Camera.GetViewMatrix(); D3DXMATRIXA16 mWorldViewProjection; mWorldViewProjection = mWorld * mView * mProj; V( g_pEffect9->SetMatrix( g_hmWorldViewProjection, &mWorldViewProjection ) );

is there any way or formula to convert :
[size="1"]axis(x,y,z) & up(x,y,z) vectors to (roll - pitch - yaw) ?

also you know we need use "axis" and "up" vector both together to calculate. because in some direction of y we must change place of x value by z ....

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i have just axis(x,y,z) vector and up(x,y,z) vector

What are you representing with these vectors? What is the purpose/meaning of the axis vector? Are you representing the axis of rotation? Have you packed an Euler triplet into a vector? What is the purpose of the up vector? Are you representing the direction the local up axis should map to in world space?

is there any way or formula to convert :
[size="1"]axis(x,y,z) & up(x,y,z) vectors to (roll - pitch - yaw) ?

also you know we need use "axis" and "up" vector both together to calculate. because in some direction of y we must change place of x value by z ....

Technically, given a single fixed axis of rotation vector, and a single localup->worldup mapping, it is possible to solve a unique rotation (unless the fixed axis is perpendicular to localup X worldup), but I am guessing you did not intend this, since you are asking "how to rotate my model by axis(x,y,z) vector + up(x,y,z) vector values?"

An axis vector alone does not define a rotation. You need to also specify the amount to rotate about that angle. See http://en.wikipedia.org/wiki/Axis-angle_representation . Alternatively, see other representations of rotation http://en.wikipedia.org/wiki/Rotation_representation_(mathematics) . Perhaps you were looking to generate a LookAt matrix here? ( http://stackoverflow.com/questions/349050/calculating-a-lookat-matrix ).

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