   from model space to camera space
  ok! if i were to have the light direction in camera space,all i have to do is to multiply the direction by the view matrix??thx!edwinz 
  1) WORLD matrix moves from   OBJECT (MODEL) space into WORLD space.2) VIEW matrix moves from   WORLD space into CAMERA space.3) To go the opposite way for either, you multiply by the inverse of the matrix. If the matrix is orthogonal (i.e. no scales/skews), you can multiply by it''s transpose.So to move an object from MODEL SPACE into CAMERA SPACE you''d multiply by the WORLD matrix then the VIEW matrix (or usually once the concatenation of the two).Usually lights are defined in world space, and geometry is defined in object space (sometimes static scenery geometry is also in world space). To simplify the computation of things like specular, lighting is often performed in camera space (i.e. the light is transformed from world space into camera space and the geometry is too). --Simon O''Connorex  -Creative AsylumProgrammer &Microsoft MVP;  hmm..okiethx alot!edwinz 