Gidday, Hope you are all well. I have been playing with a Camera class that I found on the net some time ago, it works fine. I now need to extract the camera rotation angle, I know how to convert from radians to degrees already, but the problem I have with the attached code is, so far I am using m_vFacing.z. Now this gives me 1.0 facing forward to +z, if I turn 45 deg it is now 0.5, 90deg = 0.0 135 deg -0.5 180 deg -1.0 225 deg -0.5 and so on. How could I convert this to 0 - 360 degrees, or just plain radians? HRESULT hr; D3DXMATRIX matTotal; D3DXMATRIX matRotAboutUp, matRotAboutRight, matRotAboutFacing; // bail if we haven''t moved since the last update if (!m_bMovedSinceLastUpdate){ return S_OK; } // get the rotation matrices for each rotation D3DXMatrixRotationAxis(&matRotAboutRight,&m_vRight,m_fRotAboutRight); D3DXMatrixRotationAxis(&matRotAboutUp,&m_vUp,m_fRotAboutUp); D3DXMatrixRotationAxis(&matRotAboutFacing,&m_vFacing,m_fRotAboutFacing); // concatenate them to form a total rotation matrix D3DXMatrixMultiply(&matTotal,&matRotAboutUp,&matRotAboutRight); D3DXMatrixMultiply(&matTotal,&matRotAboutFacing,&matTotal); // transform 2 of the vectors by this matrix and get the third using the cross product D3DXVec3TransformCoord(&m_vRight,&m_vRight,&matTotal); D3DXVec3TransformCoord(&m_vUp,&m_vUp,&matTotal); D3DXVec3Cross(&m_vFacing,&m_vRight,&m_vUp); // are these two still perpandicular? if (fabs(D3DXVec3Dot(&m_vUp,&m_vRight)) > 0.01){ // these suckers aren''t perpandicular anymore - get another using the cross product D3DXVec3Cross(&m_vUp,&m_vFacing,&m_vRight); } // remember to normalise vectors before putting them into the view matrix D3DXVec3Normalize(&m_vRight,&m_vRight); D3DXVec3Normalize(&m_vUp,&m_vUp); D3DXVec3Normalize(&m_vFacing,&m_vFacing); // used to compute the bottom row of the view matrix float fView41,fView42,fView43; fView41 = -D3DXVec3Dot(&m_vRight,&m_vPosition); fView42 = -D3DXVec3Dot(&m_vUp,&m_vPosition); fView43 = -D3DXVec3Dot(&m_vFacing,&m_vPosition); m_matView = D3DXMATRIX( m_vRight.x, m_vUp.x, m_vFacing.x, 0.0f, m_vRight.y, m_vUp.y, m_vFacing.y, 0.0f, m_vRight.z, m_vUp.z, m_vFacing.z, 0.0f, fView41, fView42, fView43, 1.0f ); // update the device - if we fail then return the error code hr = MyMilk3.m_pd3dDevice->SetTransform(D3DTS_VIEW,&m_matView); if (FAILED(hr)){ return hr; } // reset the various variables to reflect the new update m_fRotAboutUp = m_fRotAboutRight = m_fRotAboutFacing = 0.0f; m_bMovedSinceLastUpdate = false; return S_OK; Thanks in advance for any help TakeCare

that''s the normalize at vector, you need an axis of reference and an angle of reference then just use 2 of the 3 components of the at vector (x,y,z) that you mention and a litle bit of geo/trig and you got your angle.

Thanks for your response nhatkthanh,

what do yo mean by axis of reference?
Is that my Up y reference ?
Thanks
TakeCare.