cmiVFX has released an incredible new Houdini training video where our mentor, Vidmantas Brukstus, leads you through the making of a line-growing effect. The end result is a digital asset that you can use to grow vines, make a slime mold imitation, multiple virus effects and more. The majority of the effect is created within the vex code which is one of the most powerful aspects of the Houdini package. You will learn how to move points that stick to the target geometry and add different behaviors that control their movement. You will also familiarize yourself with the aspects of the vex code that are impossible to avoid in almost any type of vex node. This includes: iterating through geometry points, using arrays, conditionals, getting and adding attributes and more. This training video is made in a way that promotes problem solving skills. We arrive at most of the solutions through a series of trial and error. It's very important to know not only the correct way of doing things, but also the problems that some of the development paths introduce and how to avoid them. For more information read the descriptions of the chapters or check out the teaser trailer.
Chapter Descriptions :
Basic Setup
We'll start by preparing the dynamic network for the point movement. We'll be using vex code to find nearby points and iterate through them in order to find a target for our source point.
Tweaking the Goal Finding Behavior
Using "if" conditionals, storing attributes, dynamically adding and removing points from groups to add behaviors to our source point. These behaviors help define how and when our source point finds new goals and what to do with the goals that where already visited.
Drawing Lines
This chapter explains how to draw lines from the source point travel path. We'll also learn how to spawn new source points dynamically, and lastly, we'll see how to add another behavior that helps our source points to travel in a more straight line.
Adding User Controls for the Point Movement
We'll learn how to influence the movement and spawning of the source points by a color pattern on the geometry. We'll also learn how to blend this behavior with the previously introduced ones, with the help of a user control.
Making the Points Stick
This chapter explains how to stick the points to the target geometry. Later we'll see that this method does not work with animated objects. However, this exercise will later help you to understand why this approach didn't work so well.
Cleaning the Effect
Here we'll be using pragmas to tweak the user interface. Also, adding more control to the traveling points speed and general ideas on how to make the effect complete.
Adapting the Effect for Animated Objects
In this chapter we'll come back to our effect and take a look at what we need to change for it to work on animated geometry. We'll also find out why the previous implementation did not work in such a situation. In the end we'll have an effect that behaves almost the same on static and fast moving geometry.
Digital Asset
We'll revisit the subnetwork that we made in the first part and make a few last minute tweaks. We'll also save out a digital asset.
Geometry from the Lines
In this chapter I'll show you a few ways to make geometry out of the lines. However, I don't go into too much detail here because the main purpose of this chapter is to show you why I chose to visualize the effect with a shader in the end.
Building the Shader
We'll use an inline code node inside of a material shader builder to make the core of our material.
Modifying the Shader
In this chapter we'll take a look at whats wrong with our code and try to fix it. This involves making some modifications on the geometry and exporting some additional files. We'll learn how to make the final node which can be used to give the effect a few different looks.
Using What We've Built
I will use what we've made in the previous chapters with the standard Houdini material nodes to make a material. This will cover the surface model node, using noise on animated geometry, displacements and so on.
