I have been trying tweaking properties and settings but cannot find the solution. The problem is that the solid RED balls are visible through the GREEN walls which is really very unwanted.
Please have a look at the image for better understanding.
I want that the red balls should come out from the opening that has been made, and not from the walls of the alphabet L. please suggest appropriate measures and also explain why is this happening.
It might help to play around with the dynamics settings. You can get there by pressing CTRL-D for the project settings and selecting the "Dynamics" -> "Expert" tab. Try increaseing the "Steps per Frame" value. This sets how often the dynamics are calculated per frame and gives you a more precice calculation - of course it does take more time for the dynamics to calculate.