www.kraytracing.com

I have executed the Tutorial of 1.7. Very helpfull, thenk you.

At the end I do not get a clean image, the area were the ceiling matches the back wall has noise, like montecarlo noise...

Can someone tell me what parameter can be twaked to get the solved out?

Thank you in advance....

( on the tutorial it apperas clean.... I have literaly done the tutorial 3 times exactly )

Have you changed paths to larger than zero (1) to get rid of lightleaks?
Pathtracing can need quite alot of FG rays to render smooth especially in corners if you have strong indirect lights. Maybe you can upload a testimage so i can look at it.