I have an math problem in Isometric projection. I have reading an article: Axonometric projections - a technical overview. For the Isometric projection part, it give an mathematical formula for conversion 3D point into 2D point for the x part the formula is:
x' = ( x − z ) cos(30);
But i also check for wiki for Isometric Projection so i use the rotation matrices which the wiki giving, calculate myself
x' = x*cos(beta) - z*sin(beta)
The beta is define by the wiki(Y axis rotation angle, and it should be 45). So what's wrong with my math? Or is there something that i don't know about the Isometric projection?