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How to simulate smoke with pre-roll in Blender

Category : Animation, Tips and Tricks · (6) Comments · by Jun 30th, 2015

The simulation preroll

In this small tutorial we will create a smoke simulation with pre-roll, that is a cache on the negative frames in order to run the simulation for a specified number of frames prior to the beginning of the actual animation. Because of that the smoke/fire will be already initiated when the animation starts.

  no_preroll with_preroll

I’ve found those questions online and decided to write a tutorial about it, so if you are interested about the original istructions you can find them here:

Simulation issues

Blender is a great tool but sometimes it will disappoint us, not because it lacks some functionality, but because for some features there is a functionIsThereButWorksOnlyAfterBlackMagicActivation feeling…

I’ve worked with simulations in the cloth, fluid and rigid body field and the ongoing revision of the physic system is a really great and challenging task for the Blender foundation (did you said tornado in project gooseberry?)
Well, my new kryptonite was is the smoke simulation and its parameters.

How to create a smoke simulation with pre-roll

In order to do a bake of the smoke domain with a pre-roll of 100 frames(that is sufficient for my purpose, change it for your own task) you have to follow those few simple steps:

  • Set the cache of smoke domain to “External” and starting from frame -100 (desired pre-roll) to frame x (your total simulation)
  • If the smoke is particle generated set the beginning of particles also to -100 or you won’t have anything to simulate
  • Start the bake all dynamics. At the end of this process be careful because you can’t touch the timeline or scroll through time. This because if you move the time blender will rewrite (and lose) that part of the cache.
  • Now from your file system navigate into the cache folder that should be beside your blend file and delete all your negative frames (from -99 to -1)
  • Into blender refresh the cache by choosing the cache folder from “File Path” in the cache settings. This process will update the frame range excluding negative frames (starting from 1)
  • Save and reopen the file to confirm the reload and finally enjoy your pre rolled simulation!


Let me know if you encounter any issue!

This guide is tested with Blender 2.71-2.74

[Python] Add all selected bones to a new Keying Set

Category : addons, Animation, Feature, python · (2) Comments · by May 25th, 2014

Hi everybody! This time I’d like to share with you all a script that I’ve made to help and boost the animation process in Blender 2.5 – 2.6 – 2.7


In order to animate a character or any armature, is easy and fast to use animation shortcuts combined with the character’s keying sets. A Keying Set in Blender is a bunch of properties aggregated with a common name that allows the user to create new keyframest of all that properties just by pressing the key I with the proper keying set selected.