Reading through a tutorial i learned that in 3D space the matrix math helps to represent it as x,y,z,w. That is a matrix of 4 x 4. It says that the extra W (Values 0001 at the bottom of the matrix) helps make things like movement easier to deal with and that the value of W will always be 1. But i don't understand what this additional row 4 i.e. 0001 has to do in the calculation when its value is always 1 and how it results in easier movement. what will happen if we remove row 4 making the matrix 3 x 3 and do the matrix multiplication. Any help! Row 1 - > 1 0 0 0 Row 2 - > 0 1 0 0 Row 3 - > 0 0 1 0 Row 4 - > 0 0 0 1 Thanks & Regards, Pramod

Thanks for the reply. Let me take an example for addition. Let be tx=5, ty=5 and tz=5. This would add 5 to x, y and z.

Row 1 - 0 1 0 0 tx -> ( x' = x + tx )
Row 2 - 0 0 1 0 ty -> ( y' = y + ty )
Row 3 - 0 0 0 1 tz -> ( z' = z + tz )
Row 4 - 0 0 0 1

and here i got new values for x,y,z in x',y',z' after the addtion. Now what row 4 has to do here as i have already got the new required values. i am sorry i am little weak in maths!. i know that i am trying to understand something, which is difficult for me do. But it seems it would be really interesting if i understand it completely.

Thanks

pramod