Hello,

I want to define boundary condition for an object which is on a surface and we give it heat and it can expand. At first I selected the bottom surface of cube and set X=Y=Z but then I realized that the results are not what I want and are not correct. At second try I defined a reference point at the bottom surface in the middle and I used " rigid body " constraint and selected reference point and bottom surface with "pin" constraint, but still the results were not correct. I know this might be a really simple problem but I'm struggling and I would really appreciate your help on how to define boundary condition correctly. 

Thank you