I am currently doing a design study to optimize heat fins. The variables are the spacing, thickness and height of the fins. For convection, I would pick the surfaces of the heat fins. The problem is that as the program simulates the different scenarios, the number of fins changes and the convection surfaces are not picked accordingly. Is there any way to get around this? This happens even when I use the “select all exposed surfaces” option and de-select faces I do not need.