Hello,

Is there a way to foresee, in which direction will the surface be thickened? 

The question might sound trivial but I wanted to post it here for your expert opinion to understand the logic behind shell thickness assignment. 

I am trying to mimic the already known Drop-Test of a Camera problem from SOLIDWORKS Simulation Professional manual. I have modelled the Ground as a surface body exactly tangent to the camera body at one point.

While assigning the shell thickness in section properties, it is not obvious in which direction will be the shell "extruded". I am aware of the fact that one can change the Offset Definition under Advanced options. If I do not change anything, the Offset Definition is by default "None", it is assumed that the modelled geometrical surface is the Midsurface and the thickness would be assigned halfway in both surface normal directions and I have to cater for the gap in my modelling. Later on I am not flexible to specify thickness greater than the geometric gap without introducing interferences in the model. If I change the Offset Definition to Top or Bottom, it is not clear whether the surface would be thickened (in attached screenshot) towards the camera or away from the camera. Also the color coding remain unchanged. 

I would be thankful for your advices.