Quick Tips for Artists Jumping into RealFlow for 3D Simulations

RealFlow has established itself as the go-to simulation software for the 3D industry. With an intuitive interface and extremely powerful fluid and dynamic capabilities it can be seen in some of the biggest blockbusters like The Avengers, and The Lord of The Rings. If you're a 3D artist who needs to create some type of liquid simulation, whether it's for water being poured into a glass or a thicker substance like chocolate, RealFlow is a great application to add into your tool bag. Not only is RealFlow great for creating liquid simulations like vast oceans and water splashes but it has very powerful soft and rigid body tools that can be used to create things like buildings crumbling and interactions between rigid bodies and fluid simulations. RealFlow also has the capabilities of working with just about every major 3D application through the RealFlow plug-in. If you haven't used RealFlow before or you have some experience with it, this article will go over some helpful tips for setting up simulations as well as some key workflow techniques.

Exporting and Importing Meshes into RealFlow

Exporting and importing meshes from a 3D application like Maya into RealFlow is actually a pretty simple process made very easy by the RealFlow plug-in. However, there's one key thing that you must keep in mind whenever you're exporting a mesh from Maya or any 3D application: the measurements. For instance, Maya measures in centimeters, and RealFlow measures in meters. This means a mesh modeled in Maya they're modeled under a centimeter scale. So if you create a small object in Maya, for example, a model of dice may only be a few centimeters in size but when brought into RealFlow it's measured by meters. The dice becomes much bigger because what was once a few centimeters is now a few meters inside of RealFlow. This can cause some problems during the simulation process and produce some unexpected results as these objects interact with any particle systems, because RealFlow thinks this object is several meters in size. It's important to remember to re-scale any meshes you create in any 3D application to match the RealFlow scale. You can do this inside the Measure Utility tool in RealFlow which helps you determine how large the objects actually large.

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Simulate the Effects One at a Time

As you begin to create complex simulations in RealFlow that have several different effects going on, like particle systems, RealWaves, and interactions with rigid bodies it’s important that you think logically with how you’re actually going to go about simulating this particular scene.

You could simulate all those different effects at the same time, so the rigid bodies could be simulated at the same time as the particles, and so on. This could work, but it’d mean that your simulation time will be extremely slow. You also won’t have as much control over the simulation and it can be difficult to troubleshoot any issues because you won’t be able to tell clearly what might be causing a problem in your simulation.

Instead, you can simulate one thing at a time, and get each effect looking how you want. For instance, if you have a rigid body that interacts with water you can get the rigid body simulation to fall exactly how you want and cache that information out, and use the cached information of the rigid bodies to affect the particles. And repeat this same process for the particles.

Controlling Particles with Daemons

Daemons in RealFlow are essential for controlling your particle simulations. Daemons can be used to add things like gravity for your scene, so your particle simulations don’t travel off in a straight line, but they can also kill off particles.

For example, if you have a particle simulation of water being poured onto a table you’d want to have the particles die off at some point. If they didn’t get killed off, there’d be a constant build up of the particles that continue sliding across the table until they get to the end, and would continue falling into 3D space.

Without a kill daemon, the particles in this scene will fall into infinity.

In RealFlow, you can tell the difference between a kill daemon and a regular daemon by the prefix “k”. The kill daemons that RealFlow includes are essential for creating realistic simulations and controlling your simulation times. By setting up a killer daemon for your simulation it is basically telling RealFlow that you want these particles to die off at some point during the simulation. Two of the kill daemons you’ll most likely find yourself using are the k Volume and the k Age daemons.

This scene uses a k Age daemon to kill the particles based on how long they've been alive in the scene.

The k Volume daemon creates a bounding box that you can position around your simulation which basically tells RealFlow that whenever a particle leaves the bounding box to kill it. Once a particle has been killed, RealFlow will no longer calculate it within the simulation.

A k Volume daemon is helpful to make sure no popping particles are still being calculated.

A k Volume daemon is helpful to make sure no popping particles are still being calculated.

The k Age daemon allows you to set a frame number that you want the particles to start to die off. For instance, you can tell RealFlow to kill off the particles after they have been in the scene for 30 frames. You can also set variation for this kill daemon so there is some randomness to when the particles are destroyed.

When using a k Age daemon, you can set a variation so not all of your particles die at exactly the same frame.

Using Notify in RealFlow

If you have a simulation that takes a very long time to simulate it can be a time consuming process, especially if you have many other tasks that need your attention. The last thing you want to do is keep checking your system to see if the simulation has completed.

A great feature in RealFlow which is overlooked sometimes, but it can actually be a huge time saver is the notify feature. The notify feature allows you to set up your email, and the RealFlow application will automatically send you a notification to your email when the simulation has completed.

While this might be a simple feature, it’s one that can save a lot of time and allow you to work on other tasks without having to keep tabs on your simulation.

You can use this feature by going into your preferences of RealFlow and under the Notify tab put in your email address and what frame number you want RealFlow to send you a notification. So, if you want to be notified when the simulation is completed put the last frame on the timeline into the Frame Step box.

RealFlow is an extremely powerful application that is a great tool to have in your 3D bag of tricks. Whether you need to create liquid simulations or rigid body dynamics RealFlow can be an excellent way of creating believable simulations in a short amount of time. To learn more about RealFlow check out Introduction to RealFlow 2013, and continue learning with the many other great RealFlow tutorials.