a point that has the coordinates 20,20,10 for example should be projected with help of:

translate(transx,transy,transz);
rotateX(rotx);
rotateY(roty);

if(projection==true){
        rotx=0;     
        roty=0;    
        transx=width/2;     
        transy=height/2;     
        transz=300;   

}

 

translateZ = 300 is the standard value. this point projected should have the coordinates 20,20. but it doesn't..

that seems to be a problem of the "viewpoint" or something like that..