Module 2 : Matchmove/Tracking_2 EN

3D simulation

FX/CFX/Crowd

Now we’re going to take a look at a key department, FX. Yes, it can all seem a little confusing. At the very beginning of the module, we explained the difference between VFX, FX, CG..., that’s right.Well, there's also a department called FX, within VFX. This is the department that oversees anything and everything that is simulated: fire, water, dust, explosions, destruction, etc. These are 3D elements, but they are not modelled, instead they are 'simulated'. We give an initial state to small points called particles, and then we give them a kind of physical equation to make them behave like water, smoke, a tornado, a blizzard...

Of course, these points will then be transcribed into something visual that realistically resembles water or fire, but the job of an FX artist is above all to find the right parameters so that the simulation looks realistic, or corresponds to the director's vision.While the FX artists do not define the final look in terms of colour and texture, they do give their simulation an appearance, which is then enhanced by lighting and integrated by compositing.The software used, Houdini, is the star of simulation and procedural creation. However, Maya is still used on some productions.Here is a video example of a 3D simulation.

CFX

FX/CFX/Crowd

There are specialities among FX artists. There's CFX: Character FX, Cloth FX, Creature FX. The 'C' is fairly interchangeable depending on the company, but it always refers to the same thing: character-related simulations.This may involve simulating the hair and fur of creatures (Hair and Groom Artists), or the design and movement of clothes (Cloth Artists). CFX's work takes into account the movement created by the animation department and integrates their simulation over it.

Source : sidefx.com

Sometimes it is necessary to go back and forth between the two departments to achieve the desired visual result. The movement of the animation may not be suitable for the simulation.Here is a video showing how to make cat fur in 3D.The software used: Houdini, Marvelous Designer (for clothes).

Crowd Artists

FX/CFX/Crowd

Source : golaem.com

Crowd Artists are FX artists who specialise in crowd generation. The aim is to simulate a large number of people to fill a stadium, streets full of zombies, large shoals of fish, animals... there are so many examples.

CFX is used as soon as it becomes too time-consuming to animate each character separately.CFX consists of bringing a group of individuals to life, giving each of them a different movement to create the illusion that everything is natural.Here is a video showing how to control a crowd and an interesting article here entitled "Body of work: Rodeo FX on how it crafts crowds".The software used : Houdini, Golaem.

Images from the "Game of Thrones" series

Source : beforesandafters.com