Hi thanks for the reply it is really apreciated

I am really confused now though

if i have a square

x1,y1 x2,y2
---------------
| ................. |
| ................. |
| ................. |
| ................. |
----------------
x4,y4 x3,y3

and quad

u1,v1 u2,v,2
'''''_______|
/...........|
|............|
|............|
\_______|
u4,v4 u3,v3
<apologies for the quad im not too good at askii art

is there anywhere to use these coords to be able to map the contents of the square into the quad so it still holds the same shape ?

again sorry if this is obvious or i have missed the point