Groom Fundamentals

Jesus FC
Lead Groom TD
Julian CG
Junior Groomer

Before We Start.

Throughout this playbooks, we will be learning the basics of grooming, no matter the software you’re using! 

This playbook is based on the course Groom Fundamentals

We’ll be working with the 3 basics controls: flow, clumps and perstand. And at the end of this course, you’ll have a better understanding of these 3 concepts.

These concepts are extremely important for you to understand, because once you put them into practice, they will make your workflow much faster!

Chapter 1 - Flow

Each type of hair has flow. The flow by itself will be defined by how the hair moves along the way, in other words, the direction of the hair.

We can represent the flow with some guides, and we can see how the guides push other guides, which bends them, creating patterns.

The length will help define the flow, for example, with short hairs, we can see how the shorter hairs in this image have more changes in direction, and the longer hairs do not.

And this is how we are gonna define the flow! 

But the flow is only the first face. 

Let’s see an example!

On this cat, we can see a very strict direction! So before we start making our guides, we need to take a moment to understand the patterns, how the flow is working and see the different variations. Also, in this face, we can analyze the length of the hair. This is the most important step, because this will define all the other aspects!

Here is a little tip! Before starting working on the groom on the software of your choice, take an image, draw the flow, and then copy it on your model.

Chapter 2 - Clump Profile

Now that we have a better understanding of the flow, we’re gonna work with the clumps. Basically, the clumps are the union of different hairs, attracted by a single force. But part of the clump is not just the attraction, we’ll also learn about something called the profile of the clump. 

This profile will define how the attraction builds up, from the first point towards the base of that point of the surface.

Let’s see an example!

For this example, we can see that the hair is reacting as a normal clump, but for the second one, the hair is being attracted towards the center, and for the last one, is being attracted to the root.

But, if you take a closer look at this example, and we rotate to the right, we will get the control that we have on our software!

So basically, those are the controls of the profile that we manage on our software and the basic structures of the clumps.

As we can see on this image, the graph on the right controls the profile of the clump.

Note: One important thing to always keep in mind is, never do 2 clumps exactly the same, try to always change the shape!

Chapter 3 - Clump Systems

Now that we’ve learned how the clumps are generated and based, let’s see what is the structure of the clump itself!

Here’s a question that you might have, can we have clumps inside another clump? 

And the answer is yes! We can have 3 to 5 small clumps inside the big clump.

The small clumps will follow the structure of the big clump. And each small clump will have their own force of attraction.

But we can also break the main force of the big clump to create other shapes.

We can have another clump inside the second clump, but that is for very specific situations. Always try to work with 2 clumps systems, but if at the end you think you need just a little more details, you can add the third clump system.

Chapter 4 - Clump by Clump

Let’s see how all that we have learned about clumps, it’s applied to practice! 

First, we’re gonna create the big clumps.

Then we create another clump system under the one that already exists.

(For this example, we put the profile or the force of attraction almost at the base so you can see the amount of small clumps created under the big clumps.)

This will be the blocking stage of your groom, so you can put the amount of small clumps that you want, under the big clumps. For this we use something called density mask, that we will see in the xgen tutorial.

Chapter 5 - Clump Modifiers

Now that we’ve learned how to create clumps, let's break them! 

First, let’s play with an attribute that at this moment of the course, you’ll be very familiar with, the force. (Mask in Maya/Blend in Houdini)

By changing the force, you’ll be changing how much hair is attracted to the center of the clump.

The force is the first attribute that we can change. The second value or attribute, is the force that we can apply to the strand, also called Noise.

With this attribute or value, we can deform the clump. Also it’s completely different and unrelated to the force! For example, we can still have the deformation and we can change the position of the force.

In this image we can see that the Noise applied to the strand is the same, but the force or mask has changed. 

The Noise has 2 values, the first one is the scale.

The scale dictates how much the shape is going to move along. Also we have something called the frequency, that represents how often the shape of the scale will appear.

In almost every groom, you’re gonna see a mid level frequency, like in this picture! 

So, when you work with the clumps, you can play with the force, the noise and the scale. With these 3 values, you can create simple to very complex grooms!

Chapter 6 - Clump Mask vs Tightness

Now, let’s try to understand the concept behind the clumps.

In the previous chapter we saw how to break the clumps, but now we are gonna see other ways to open up the clumps!

First, we’re gonna create a big clump.

Now that we have our big clump, we’re gonna create a second clump system inside the big clumps.

Once you have created the second clump system, let’s see what happens if we remove the force from the main clump.

The big clump will have no force of attraction, but what will happen to the second clump system?

They will not follow the shape of the big clump, as simple as that! And this is what we get.

And here is where it gets a little trickier. We have 2 forces, the force of attraction (also called mask or blend), meaning the profile that we learn back in this course, that we are gonna represent like this.

This is the force that is produced from the curve or from the center of this curve towards the edge. And we also have the attraction force.

When we reduce the attraction force, it will still preserve the shape that is coming from the noise! But let’s see what happens if instead of reducing the attraction force, we reduce the mask!

The shape of the noise is lost as well as the clump. And this attraction force it’s also called tightness. 

Now let’s see how this looks in a 3D software (Houdini).

First we create our clumps.

Now let’s see what happens if we reduce the blend.

The clumps are not attracted anymore!

But instead of removing the blend, let’s see what happens if we reduce the tightness? In this case it will have the same effect, because our guides are straight, but what will happen if they're not?

The hair will still be affected by the shape of the noise!

Chapter 7 - Clump Break Up by Noise

We just learned how to break the clumps with the mask and tightness, now let’s see how we can break them with noise.

If we have a tight clump we can break it in 3 different ways:

  • Blend
  • Tightness
  • Content behavior (Everything that is inside the clump)

For  example, if we apply noise to a clump, it will break. But with the noise you can decide which part of the clump you want to break, for example, you can only break the tip of the clump, but for that, will need to create an influence mask.

Let’s see an example!

Here we have some basic clumps.

As you can see, the hairs are following the clumps. But, now let’s add noise!

We can see that now the shape was broken, but there are still some hairs following the shape. This will add some texture to your grooms!

Now let’s put it into practice.

First we’re gonna create a 2 system clump.

Then change the frequency of the Frizz (noise) on the big clump.

And now we have a shape that is broken by the noise.

And If we add the noise to the small clumps, the shape will be totally broken.

Chapter 8 - Clump Break Up by Length

In this last chapter, we’re gonna learn other modifications to break the shape of the clump.

The first one is the scale that will increase the shape.

We also have the increment, that will take the shape and increase according to the total length.

Increasing the length can be tricky, so a little advice is to increase the length by preserving the shape. At the moment when the shape changes, it’s time to stop increasing the length!

And the last one is the cut, that will have a shorter amount of hairs and the clump will not reach.

Now that we have seen the 3 options to modify the length of the clump, let's put them together!

But, let’s put it into practice!

First with the scale, as we saw previously, the scale will change the length of the shape as one entity.

But with the increment, we can see how the shape is being broken.

And when using the option to cut, the clumps will not reach the full shape of the big clump.

And the fun aspect of these tools is that you can play with them to create different shapes!

And you can also play with these attributes on the strands, to make more complex shapes, like fuzzy characters.

And now you know the fundamentals to groom your own characters!


Always remember to do a hair flow analysis before opening any grooming software. This will give you a better understanding and will make your job much easier when creating the guides!

Now that you have the basics, it's time to groom your own character! For that, we leave you these playbooks, so you can continue your journey to become a groomer:

  • Houdini for Groomers. And if you want something a little more advanced, go check out Houdini for Groomers, and learn how to groom in Houdini.

Thank you for reaching the end! 

See you on the next one!

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