What is the implication of dotting a vector and a matrix and resulting in another vector like this?

D3DXVECTOR3 dot(D3DXVECTOR3 t1, D3DXMATRIX t2) { // x = ax + by + cz // y = px + qy + rz // z = ux + vy + wz double x = t1.x * t2._11 + t1.y * t2._12 + t1.z * t2._13; double y = t1.x * t2._21 + t1.y * t2._22 + t1.z * t2._23; double z = t1.x * t2._31 + t1.y * t2._32 + t1.z * t2._33; return D3DXVECTOR3(x, y, z); }

When dotting a vector against another vector, I get a scalar, it tells me how the vectors are separating.

But I don't know the true meaning of dotting a vector against a matrix that results in another vector of sums

Thanks

Jack