Custom polymers crashing the game

Well, I was originally going to ask what the line would be for specifying a Poisson's ratio as someusername6 suggested to do (just PoissonsRatio, or Poisson_sRatio, or something else?), assuming it's even been programmed in for the game to read, but I figured if it's not much trouble then all bases could be covered, as it were, to ideally make the game more stable under these conditions. The main other things would be cost and thermal diffusivity. Maybe electrical conductivity too, but I don't know enough about electricity to say whether that would have a use case.