On 02/10/2014 01:28 PM, Matthias Goldhoorn wrote: > Don't know that this results in a problem: > > State.buoyancy = Robot.buoyancy_def! > > it's only a cache for me i could save "true" here instead... As always, it should either be OK or raise when you assign. But yes, that is the line that cause problem right now. Sylvain