Scattering – simple on the surface, but below it’s all driven by you know what – attributes. In this course we’re diving deep into controlling attributes using noise and random functions, and learning how to manipulate attributes using colour correction techniques. These are essential skills for creating awe-inspiring environments and richly detailed objects. Best of all, you’ll learn how to precisely control the distribution of values, and it’s this knowledge that will serve you time and time again in all kinds of procedural workflows.

Section 01

Noise Versus Random

They say variety is the spice of life. We say the ability to automate variation is crucial in procedural workflows. A little less catchy, but no less true. Houdini’s noise and random functions help us do this in different ways. We’ll examine their technical differences and cover practical examples for each one – like using noise to create natural and organic distribution, and using random to avoid patterns and trends.

Lessons

1. Noise vs Random: Graphing the Outputs
2. Noise vs Random: Relationships and Trends
3. Noise vs Random: The Organic Nature of Noise
4. Noise vs Random: Comparing the Distribution Ranges

Section 02

Distribution & Density

Strap in! It’s time for a new practical project. This one’s all about controlling the distribution of geometry across surfaces. These are the skills you need to craft realistic environments, like grassy fields, lush forests, or in our case, clumps of mushrooms. We’ll teach you how to combine random functions with point relaxing to get the ideal spread of clumped vs evenly spaced points, and how to create masks with attributes to dictate exactly where your points should and shouldn’t go.

Lessons

1. Exercise Intro & Scattering Points
2. Running Over Numbers & the Clumping Nature of the Random Function
3. Point Relaxing
4. Working with Point Density
5. Controlling Point Density with Attributes

Section 03

Correcting, Adjusting & Compositing Attributes

We’re not done with those mushrooms yet! Picking up where we left off, we’re continuing our practical project and taking you even deeper into attributes. You see, attribute values are a lot like pixel values. All the techniques you’re used to using in image editors like Photoshop can be used to manipulate attributes in Houdini. Neat, huh? We’ll look at three classic colour correction tools in COPs and show you how you can use VOPs to make the same changes to attributes.

Lessons

1. Geometry Resolution and Attributes
2. Comparing Attribute Values to Pixel Values
3. Correcting the Noise Output: Colour Correct & Levels
4. Correcting The Noise Output: Curves & Ramps
5. Compositing Attributes
6. Working with the Mask Controls

Section 04

The Relationship Between Attribute VOPs and Attribute SOPs

Houdini is far more than a set of tools for creating amazing content, it’s also a framework for creating our own custom tools. If the tool we need doesn't exist, we can create our own. In this section, you’ll see how learning essential VOP nodes in the last course has provided you with not only the components you need for building your own operators, but also the knowledge to help you understand and navigate a multitude of new and different SOPs.

Lessons

1. Replacing an Attribute VOP with the Attribute Adjust SOP
2. Houdini as a Framework for Creating 3D Tools
3. Using Noise to Control Size

Section 05

Controlling Random Value Distribution

It might sound counterproductive to try and control randomness, but trust us, generating random values and dictating their distribution can indeed be done with accuracy and finesse. The random function is used by many different surface operators, so to really get to grips with it, we teach you how to use the Gain and Bias VOPs, along with ramp parameters, to command your random values with precision.

Lessons

1. Randomising the Scale Attribute in VOPs
2. Controlling Random Distribution Using Bias & Gain
3. Graphing the Bias & Gain Controls
4. Controlling Random Distribution Using a Ramp Parameter
5. Comparing the Custom Built SOP to the Attribute Randomise SOP

Section 06

The Scatter and Align SOP

Houdini’s tool-building capabilities are in the spotlight once again as we step through a magnificent recent release from SideFX – the Scatter and Align SOP. Brimming with aha moments, this section puts a tonne of your previous learnings into play as you master using this new node to scatter points, control randomness and, most significantly, generate and control the Orient attribute.

Lessons

1. The Scatter & Align SOP: Scattering Points
2. The Scatter & Align SOP: Randomising Rotation
3.The Scatter & Align SOP: The Orient Attribute
4. The Scatter & Align SOP: Adding Attributes to Existing Point Clouds

Section 07

Testing and Optimising

It’s all about improving the efficiency and flexibility of our networks as we wrap up this bumper course. The order of operations comes under the microscope, and point count goes under the knife. Once again, we draw parallels between working with pixels and working with attributes as we use masking and attribute blurring to isolate the regions of geometry we want to operate on.

Lessons

1. Distributing on Different Terrains & Objects
2. Optimising the System - Order of Operations
3. Optimising the System - Region of interest
4. Summary