bemfarmer
Thank you! I'll fix it. :)

Karsten
>>Unfortunately the function gives confusing results and crashes in particular situations
Which parameters could cause a crash?

>>After a look in the code I saw one thing that causes definitely a problem:
>>ry = -Math.asin(frame.zaxis.x);
What's wrong with this line? The frame.zaxis.x value is always in [-1...1]