Generating Distinctive and Dynamic Wrinkles for Toon Characters

Introduction

Greetings, this is Peter Alexander. In this video I’m going to demonstrate how to use the wrinkle system for a stylized character.

Overview

There will be two main sections to this tutorial: one for basic users, and one for advanced. The advanced section will delve into areas of normal map modification.

Software Used

I will be using Character Creator and an image editor known as Krita. I chose Krita because it has a height-to-normal map filter, which is very useful for non-3D generation of normal map details.

Part One: Basics

Understanding Wrinkle Maps

The wrinkle system uses three sets of maps, with 5 main maps in total for each set.

Loading a Wrinkle Map

The process of adding wrinkles to a character is very simple. Just find a preset in the Wrinkle tab of the Content window, which is a subsection of the actor properties.

Character Creator has some facial animations preloaded to the animation player, to allow you to check your wrinkles and other animation properties.

Choosing the Right Set

After experimenting with the realistic sets, I’ve decided to apply the stylized wrinkle presets included in the “Wrinkle Essentials” package.

Keep in mind that you can only apply one wrinkle preset at a time, meaning one preset will overwrite the other; but you can manipulate and combine maps from multiple sets.

Using Wrinkle Settings

Once your wrinkle preset is loaded, you can play around with various settings in the wrinkle panel under Modify.

You can adjust the overall influence of the set, and below that you can select parts of the face and apply strength settings to the active part. The strength settings are divided up by map effect. Normal maps provide much of the detail, while ambient occlusion and redness are significant components, especially for more realistic characters. There’s also the speed of the wrinkle effect, which I do not have much experience in using.

Adjusting the strength for part of the character’s face can be important for a character with, say, a large forehead but a small mouth, or other combinations of exaggeration.

Part Two: Advanced

In this part of the Demo, I’ll show you a method for combining wrinkle map effects with a custom expression.

Where to Find More Info

Without getting into the exact mechanics of this system, which I’d not be fully accurate in describing, I will say that the expression sliders are linked to the data, which triggers the wrinkle effects.

If you want a more in-depth overview of the relationship between the sliders, wrinkle data and textures, I highly recommend going to the Reallusion webpage linked here. There it kind of goes under the hood of the technology and its features. I’d especially point to this breakdown.

These texture maps are the final textures, which generate the wrinkle effects. Below this is the tier of textures I previously mentioned.

Which Map Normal to Edit

It can be a tad confusing, especially if you don’t know what all these textures do. That said, the final texture map is a combination of maps. For example, the character’s normal map, and the normal map, would blend together, like this.

However, you don’t want to edit the result, but the wrinkle part of this equation — which would be this map here:

Using Wrinkles with Custom Expressions

By default, custom expressions are not linked to the data which triggers wrinkles. Even if you were to use sliders with wrinkles and combine them into a new custom slider, the wrinkle data would be lost. There are ways to use wrinkle data with a custom slider, however. I will go over one such method.

Step 1)

Dial in your expression components or utilize one of the presets in the facial editor. These presets are linked to the expression components which trigger wrinkles. Once your expression is dialed in, save it as an expression asset.

Step 2)

Open the facial profile editor. Your expressions will be reset while in this editor for better editing. However, you can apply the expression preset you just created. This will dial in the various sliders which comprise your expression. Send your character to a sculpting application, preferably ZBrush.

Alternatively, you can use the mesh editor, which can perform basic mesh sculpting functions.

Step 3)

As you edit your expression, note that the final expression should be a fix, enhancement or exaggeration of the original expression , as it will use the same wrinkle data.

Step 4)

While still in the facial profile editor, your character should now have the combined expression dials and the sculpted data. Now reset the expression sliders, leaving only the sculpted data.

Step 5)

Bake the remaining changes, the sculpting data, as a custom expression.

Bringing it Altogether

You can apply both your expression preset and the custom slider you just created. This combined data can now be saved as another expression preset, which will trigger the wrinkle data.

This final expression is now a combination of many partial expression sliders, and one custom slider. Each of these can be adjusted independently.

Limitations

Keep in mind that unless another character has a custom expression of the same name, only part of this data will apply to other characters.

Choosing the Right Wrinkles

Now to apply a wrinkle set. I will start by experimenting with some of the realistic sets. While the realistic sets are great, it is not the style I am looking for. The stylized sets have some chiseled wrinkle effects, which suit this character better.

The “Groove” set is almost perfect, so I will export the maps and tweak them slightly in Krita, a free painting application.

Editing Wrinkles in Krita

What I am going to do is add a bit more emphasis to certain areas. I will do this by painting in displacement detail, then converting it to normal map detail with a filter Layer.

Why Krita

Krita is a great tool for 3D artists as it has been developed with texture artists in mind. There is a filter layer called “Height to Normal Map”. Add this layer below the original normal map, and then set the original normal map’s blending mode to “Overlay”. This will combine the two normal maps. A third paint layer will allow you to add height. However, to add negative height, you will need a gray layer below the paint layer. So, I will add a fill layer with gray selected.

The gray layer allows the “Height to Normal Map” filter to read black as a negative value.

I’m now painting on the paint layer with white, and occasionally some black. Black basically allows you to add deep cuts to your normal maps.

The original normal maps in this case are mostly cuts into depth, rather than elevation. As this expression is a boxer being struck in the face, I figured some height would add more emphasis. You can use tools and brushes like smudge and erase to soften and remove detail. The Layer above it calculates the changes, so you don’t have to worry about the technical aspects of painting a normal map. Since there are three normal maps to edit, you get to practice this procedure three times:

Create a gray fill layer.
Add a paint layer for displacements.
Add a filter layer with “Height Map to Normal Map” selected.
And drag your original normal map to the top, with blend mode set to overlay.

Other Methods

I’d also like to point out that you can use ZBrush, 3D-Coat, Blender or other applications to create and edit wrinkle maps. This is probably the best 2D method, but 3D sculpting and texture painting applications have significant advantages. Just remember that you do not have to start from scratch. Use the presets as both a guide and foundation for any changes you make.

Similarly, when crafting a custom expression, you can use the facial presets as a starting point, especially the components of those presets are linked to wrinkle data. Back in Character Creator, you can load the wrinkle maps from the folder containing the changes you were just working on.

Depending on your changes, the effects may be subtle or extreme. It takes a while to get the right look. The changes I implemented are not too extreme, but there is a noticeable difference compared to the originals.