Instancing: A Primer with TouchDesigner

Greetings TouchDesigner developers! In today’s post we will be focusing on one of the most popular and beginner-friendly techniques when you’re first diving into TouchDesigner: Instancing. At first, it might sound complex or technical, but it’s really about making your projects more dynamic and efficient. At its core, instancing lets you duplicate objects without bogging down your computer. This article aims to clear up the basics and answer the questions we’ve seen most beginners grapple with. Whether you’re trying to get a clearer picture of what instancing is or looking for ways to improve your projects, we’ve got you covered.

What is Instancing?

Instancing is a technique widely used in computer graphics to efficiently render multiple copies of the same object. When you’re working with 3D environments, particularly in software like TouchDesigner, instancing allows you to create a multitude of objects from a single source model.

The magic of instancing lies in its ability to use resources smartly; instead of duplicating the object’s data (like its geometry) for every instance, it reuses the same data. This means each “copy” appears in the scene without the need for additional memory or processing power to describe its shape. Instancing can be thought of as a clever illusionist’s trick: it makes the computer think there are many unique objects when, in reality, it’s just one object being repeated. This efficiency is particularly useful in real-time visualizations, interactive installations, or any project where performance and resource management are critical. What makes this even more powerful is that this instancing is done exclusively on the GPU. Once the GPU has one copy of the object, it can spin up hundreds of thousands or millions of copies with ease.

Applications of Instancing

Instancing is not just a technical trick; it’s a practical solution applied across a broad range of fields. For example, in video game development, it allows for the creation of lush, detailed environments filled with flora, fauna, and other objects without straining the system. VFX artists use instancing to populate scenes with countless particles, like raindrops or snowflakes, making scenes come alive realistically.

By leveraging instancing, creators significantly optimize their workflow and resource management, making it possible to handle complex scenes with many objects efficiently. This efficiency is crucial in projects that require real-time interaction or high levels of detail, as it ensures smoother performance and a better user experience without compromising on visual quality. One thing most beginners notice when they look at professional TouchDesigner projects is how much instancing techniques get used to create all kinds of content and effects. Mastering instancing is a necessity in immersive media development.

The Origins of Instancing

The origins of instancing trace back to the early days of computer graphics when rendering detailed 3D environments was a significant challenge due to limited processing power. One of the earliest and most notable uses of instancing was in the video game industry, where developers sought ways to create rich, immersive worlds without overloading the system. A pioneering example can be found in the 1980s and 1990s video games, where instancing was used to populate landscapes with multiple identical objects, such as trees and enemies, to save memory and processing resources. This technique allowed games to run smoothly on the hardware of the time while still offering visually engaging experiences. As technology advanced, instancing evolved, supporting more complex implementations, utilizing the parallel power of GPUs, and became a standard practice in real-time graphics and beyond.

Benefits of Instancing

Instancing offers numerous benefits that make it indispensable for us digital creators! Here are three key advantages:

Efficiency in Resources: By using a single set of data to render multiple instances, it significantly reduces the memory and processing resources required. This is especially critical for complex scenes or real-time rendering projects.

Performance Boost: Instancing minimizes the workload on the CPU generally and takes full advantage of the graphics processing unit (GPU), which does parallel processing of data sets with ease, allowing for smoother performance and higher frame rates. This is crucial for applications like video games and interactive installations where user experience depends on real-time feedback.

Scalability: With instancing, creating vast, detailed scenes becomes more feasible. We are able to populate environments with thousands of objects, such as trees in a forest, without a corresponding increase in computational load. It’s the draw people have towards GPU-accelerated particle systems because they take advantage of similar scaling power of GPU data crunching.

Downfalls of Instancing

While instancing brings a host of benefits, there are some limitations and challenges to consider:

Complexity in Management: As the number of instances increases, managing them, especially if they need individual adjustments, can become complex. It is prudent to be mindful of the process from the very beginning, so as to not render an unmanageable environment to work with! In TouchDesigner, this often manifests as complex CHOP networks that can make even a pro dizzy.

Visual Repetition: Over-reliance on instancing can lead to a visually repetitive environment if not combined with other techniques to introduce variety. Fortunately, TouchDesigner offers many ways of introducing variation and visual-relief in instancing setups, like patterns or LFOs for translation, size and animations variances.

Hardware Dependencies: The effectiveness of instancing can depend on the hardware, particularly the GPU’s ability to handle the instances efficiently. This is natural: the more efficient and powerful system you are working with… the crazier you can go in your experiments!

Instancing in TouchDesigner

Before we get into some examples of instancing inTouchDesigner let’s lay down a few foundational concepts:

Geometry COMP: The building block for any instancing setup. You’ll start by creating a Geometry COMP that will house the geometry (SOP) that you want to instance.

Default Instance Operator (OP): From your Geometry component, you’ll use an operator as the basis for your instances. TouchDesigner allows you to use attributes of this operator to drive the position, scale, and rotation of your instances. Often times you’ll see SOPs or CHOPs used for this, but it’s becoming even more common now to see TOPs used for this. Previously there was only one operator which could feed data into the instancing setup but now you can use a separate operator for each attribute you’d like to control, which makes it much easier to manage your network.

Now, let’s go ahead and set up some instancing environments!

Instancing with SOPs and TOPs

Using a SOP (Surface Operator) for instancing involves creating multiple copies of a geometry based on the input from a SOP. You’ll typically use this method to position, scale, and rotate 3D objects in your scene. The setup involves connecting a SOP to a Geometry component and then using instance parameters to control each copy’s attributes, such as their positions or orientations. 

As a simple example let’s instance a Box SOP with a Grid SOP as the instance operator. Here is the setup:

Now, of course there will be a downloadable project file with this network for you to explore as the bottom of the page. Here is the rundown of what is happening in our network:

• We start with a basic shape, such as a box, which will serve as our source geometry for instancing.

• We arrange the instances using a pattern generator, which places each copy of the box at specific points in a grid-like formation. The Grid SOP acts as our instance operator for our Geometry’s translation parameters. 

• Don’t forget to Include a camera view to observe the layout from a particular angle, enhancing the visual understanding of the instancing effect. Perhaps at a later point in time you can animate this camera to explore our instanced object in a more cinematic manner.

• We also incorporate a light source to illuminate the instances, adding depth and shadows for a more realistic appearance. Keep in mind that the material we are using in this case is a Phong operator, which needs a light in order to perform!

• Explore the Phong material to define instance surface characteristics, like color, reflectivity, and texture. Be mindful to explore other materials like PBR or projected TOPs with a Constant operator.

Variance and Animation

Ultimately start exploring other operators to create variance and avoid boring repetition. There are two examples here: 

1. In this case, we are using a Pattern CHOP to display varied scaling for our instanced objects! Since we are using a Ramp pattern, you’ll see that different scale instances are created in an organized manner, from smaller to larger. 

• For this technique, keep in mind that the samples of the CHOP operator must match the number of points of our instance operator. In the case of our pattern CHOP we have referenced the number of points of the Grid to the pattern’s samples. If you miss this step, you’ll get an error in the Geometry COMP.

2. Next, we can use a Noise TOP in order to control the Y scale of our instances. In this case, values from 0 to 1, in channels RGB, determine the scaling.

• In the case of the TOP instancing we have set a resolution of 10 x 10, matching the grid’s number of points!
• By animating our Noises’ Transform in the Z axis, we now have a dynamic setup, making the scale vary according to the RGB values.

For exploring both scenarios simply reference an operator of your choosing: either the Pattern CHOP or the Noise TOP (referencing the null at the end of each chain.) in the Geometry’s Instancing Operators: Scale OP. 

Also, be mindful of choosing your reference channels: in the case of the CHOP it will be p(0), p(1), and p(2). And in the case of the TOP it will be channels R, G, B, A. There is a handy triangle on the right side of these parameters that can help you find the channel names that you need to reference.

Project download

You can download a copy of the example project here:

Wrap Up

Wrapping up, we’ve journeyed through the essentials of instancing in TouchDesigner, from its basics to the practical steps of creating instances with SOPs and TOPs. As you venture into your own projects, remember that instancing is a tool to not only bring efficiency and performance but also to spark creativity. Keep experimenting with different operators, explore variations, and push the boundaries of what you can visualize and animate. May your scenes be as dynamic and resourceful as the instancing technique itself. Until next time!