I like to print in PETG and use PLA for my dense support... but I recently got a heater fault which I believe was caused by the cooling fan blowing air into the object which then directed the air back to the nozzle. I realized that the cooling fan was on and at 100% for the PETG tool. Not at all what I wanted. But it seems ... at least with S3D... that you cannot control the downward fan per tool. It's whatever the setting is and it goes to all the tools. Is this just mine and my use of S3d or is this controllable using another slicer??? Edit: DOH! Forgot about the fan control line in the tpost files!