This chapter requires that you have Blender version 4.2 or above installed. To download Blender, visit www.blender.org.

You can find the assets for this chapter in this book’s GitHub repository: https://github.com/PacktPublishing/Learn-Blender-4-Simulations-the-Right-Way/tree/main/Chapter%201.

Mantaflow is the framework in Blender for simulating gas and liquid. Mantaflow was introduced in Blender 2.82 and has seen many updates since then. It was first developed back in 2009 at the ETH Computer Graphics Laboratory. Now, it’s being maintained and developed by the Thuerey group at the Technical University of Munich (TUM).

In Blender version 2.81 and below, the smoke and fluid simulations were two completely different things, and they weren’t very compatible with each other. When 2.82 came out, the Blender developers removed these two simulations and introduced Mantaflow. This was a much better system because it combined both the fluid and smoke simulations into one.

To enable Mantaflow on an object, you need to head over to the Physics properties area (it will look like a circle with a dot in the middle) and select Fluid:

Figure 1.1 – Blender’s Physics properties area

Don’t get confused...

You’ve seen me throw around the terms gas, liquid, and fluid, but what are the differences? As mentioned previously, Fluid is used to describe the entire simulation. Inside the simulation, there are two options to choose from:

• Gas: Used to create things such as smoke, fire, or airborne solids
• Liquid: Used to simulate things such as water or honey

Let’s talk about each one separately so that you can understand the differences between them and how each one works.

Gas simulations

Gas simulations allow you to create smoke and fire in Blender. But what can you do with it? Well, you can combine fire and smoke to create a massive explosion. Other examples might include a flame thrower, campfire, steam, mist, or fog.

Figure 1.2 – Flame thrower example

There so are many things that you can create, and the possibilities are almost endless. The following figure shows what we will learn to...

In short, there are two things you will always need for a Mantaflow simulation, as follows:

• A domain object
• A flow object

We will look at each in more detail, along with effectors, which are not mandatory but are still useful.

Domain objects

A domain object is the container for the entire simulation. No gas or liquid will be allowed outside this domain. When the simulation gets close to the edge, it will either collide or disappear, depending on what setting you have set.

The bigger the domain, the more resolution you will need

This will cause the simulation to bake longer. A general rule is to have the domain just big enough to fit the simulation.

The domain object is always going to be the shape of a cube. Even if the domain isn’t a cube, the simulation will treat it as one and will simulate outside the original mesh:

Figure 1.8 – Domain example

The sphere in this...

Now that we understand what creating a Mantaflow simulation in Blender looks like, let’s create one together. In this section, we will go through the entire process of creating a fire simulation in Blender; this process will include doing the following:

• Adding the objects
• Creating the simulation
• Creating a material for the fire
• Setting up the camera
• Rendering the animation

This may sound like a lot but don’t get overwhelmed. I will be going through every step, and together, we will create something awesome! This section is aimed at beginners, but it also assumes you have basic knowledge of Blender’s interface and how to use it.

With that out of the way, let’s get started!

Adding the objects

Let’s start by adding the objects we will need in the scene. Remember, we need a domain object and a flow object for every simulation. With the default scene open in Blender, we already have...

If you have never touched Mantaflow simulations in Blender until today, congratulations on making it through this chapter and creating your first fire simulation!

We covered quite a few topics in this chapter, so let’s recap! First, we learned what Mantaflow is and how it was introduced to Blender. We looked at what creating a simulation is about and the two types to choose from – gas and liquid. We also covered all the objects you can add to your simulations – that is, domains, flows, and effectors.

After that, we worked together and created an awesome fire simulation. Using Mantaflow can be a bit challenging at times but, hopefully, this chapter gave you a clear understanding and a boost of confidence to go and create simulations!

I encourage you to open Blender and try to create a simulation and have fun with it! You can do something interesting such as setting a custom text object on fire and having the color of the flames be purple! Or you...

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