Pyrotechnics, the art of making fire, is possible to add to video and at Cutting Factory we’ve started work on a project which involves creating a fire for an animated character. Every job assignment requires a different approach, either filming or 3D, and for this, we chose the 3D route, because of the control you have over the fire. Also, it’s somewhat safer than it would be to film!

Creating the Pyrotechnics

To create fire we need to use a digital container filled with data, which in this case, uses temperature, density and heat to form the basis of the fire. We use a velocity vector to push the data inside of this container and this reaction gives us a resulting explosion. We use particles as additional velocity to simulate the fire movement. Particles are essentially very small, simulated dots, which are then made to move in particular ways; up, down, left, right and in a randomised way. They are also easy to control, so therefore they are perfect to use in this case. This is what gives the fire it’s real-life effect.

Why can’t I Just Film Fire for an Animation?

Fire is a very detailed process and is not something that can simply be cut out and pasted into a video as someone can with images in Photoshop. The detailed movement needs to be recreated from the bottom up, in order for the fire to be clear and also for there to be controlled as to how much fire you want or need. Filming is also not advised due to the usual logistical issues that come with many things related to filming. It often requires outside space (which is not always easy to come by in a big city), there are safety risks involved and the resulting film is much harder to work with.

What Software do you use to Make Fire?

To make fire, our team uses a program called Houdini which is the software that we use for all detailed movement and assets that need more sophisticated actions. Houdini is the perfect software, as it allows for multiple, complex simulated effects and particle work using their unique node structure of working. This allows our artists to create such works like fire, and even water, wind etc. We’ve also used Houdini to mimic sand and sand movement for a short film focusing around a horse, so it’s uses are very broad.