Reply To: The collision physics are not rendering. The smoke is just going through the floor but when I play it back in the viewport render it looks correct. What am I doing wrong?

Yes, indeed, tweaking the settings for the particles can lead to outdated data in the particles cache. Refreshing the cache by changing for example the cache step number and then resetting that  number to the old vaulue (mostly step size “1”) should solve this problem, too. Baking the particle simulation nevertheless should always be done before the final rendering it in order to have all physics simulations in your scene up to date.