Thanks for your reply Mirko.

I did try navigating thru that stuff many times before and I always find myself lost trying to make sense of it. If for example I want to know the pressure exerted on a wall patch, how would I find out the right class/method/whatever that I need to implement just by using the source code documentation that you referred me to? Also, I dont fully understand how those arrow charts can help me. I will appreciate any hints. Thanks again