Mia

Character Breakdown

Renan Garcia

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Renan Garcia

Character Artist

Introduction

My name is Renan Garcia, and I'm Brazilian. I've been working professionally in 3D for about 4 years now, but my passion for the field started back in my childhood.
I began "playing around" with level design for games like Half-Life in 1998 and CS 1.6.

Since then, my fascination with game development and 3D creation has only grown, leading me to specialize in creating 3D characters for games and cinematics.

Introduction

In this article, I chose to highlight specific aspects of character presentation, setting aside the detailed modeling process, such as creating clothing and hair, among others.

My focus will be on rigging, facial and body animation, specific VFX material, and the overall physics applied to the character. The article is not intended to be a tutorial but rather to provide a brief overview of the process used at each stage.

Tools

  • ZBrush
  • Maya
  • Blender
  • Marvelous Designer
  • Substance Painter
  • Unreal Engine 5
  • Embergen

References

The context of my character is that of a military woman who suffered a serious accident on her left arm, resulting in amputation. However, the replacement of human limbs with robotic ones was common, and she gained access to a military test mechanical arm.

Taking this into consideration, I searched for references on Pinterest and ArtStation that suited my character. Below, you can see some of these references that inspired me.

The idea is to create something new, without relying on a single reference or even predefined artistic concepts.

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Rigging

This is one of the most important parts of the article, and my intention is to provide an overview of the process for you, the reader. I recognize that it is not feasible to present a detailed tutorial here and cover the entire process, but I hope to convey the essential concepts.

It is important to note that this process requires knowledge in rigging, but there are plugins available that can significantly ease the work.

Rig Facial

As I am using the MetaHuman rig, I chose to use the MetaHuman base mesh and apply the ZWrap plugin to my high-poly face model.

Then, I imported the model into Maya and transferred the rig to my new mesh. After this step, transferring the bone weights from the eyebrow and eyelash region to the corresponding meshes was a challenging task.

I had to redo it several times because distortions occurred when the character moved her eyebrows.

Body Rig

At this stage, the process follows a similar line to facial rigging. I used ZWrap with a MetaHuman’s basemesh on my character’s high-poly model. It is important to highlight that adjustments to the rig were necessary to ensure proper fit and functionality.

For the clothes, the procedure was simpler: I just needed to import them and transfer the weights of the corresponding bones.

Overall, it worked without issues on the first try, requiring only minor influence adjustments. However, the development of the mechanical arm posed a significant challenge.

Each part of the fingers and hand is independent, requiring detailed precision in the bone weights to ensure they correctly influenced the specific responsible parts.
This precision is crucial due to the robotic nature of the arm, which demands realistic and functional movements.

Important Note

When working with MetaHuman, it is crucial to understand that the facial rig will only function correctly if the mesh is identical to the original.
This is due to transferring morphs after using ZWrap and importing them into Maya.

However, in the case of the body, the situation is different and simpler. Since there is no use of morphs, transferring weights between meshes will ensure proper functioning.

Therefore, despite the need for weight corrections, it was possible to use different meshes for the clothes successfully.

Realistic Eyes

MetaHuman itself has incredibly realistic eyes, but if you only add the eyeball to your character, it may appear to have a “lifeless” expression, like that of a fish.

This process is essential to make the face more natural and consists of two complementary meshes: Wetness and Fake AO.

Wetness is crucial to give a moist look to the corners of the eyes and a slight blur in this area.

Fake AO, on the other hand, is essential to create a subtle shadow on the upper part of the eyes, adding depth and realism to the overall appearance.

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Here is the comparison between the applied effect and its absence:

Retarget Anim

In my case, the animations belong to a similar skeleton.

However, if you are using animations from different sources, such as those available on Mixamo, Actor Core, or a different skeleton altogether, you will need to perform the animation retargeting process.

Although it is not a complicated task, providing a detailed description or step-by-step guide for this procedure is beyond the scope of this article. Fortunately, there are plenty of resources available on the internet that delve deeply into this topic.

But if you are using animations from MetaHuman itself but on a similar skeleton, here’s how I did it to make my skeleton reference the animation from another skeleton.

Steps for Retargeting

1: With your animation open, open the skeleton tab.

2: Open the Retarget Source panel (located in Windows).

3: In the Manage Compatible Skeleton option, add the similar or compatible skeleton.

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Note

You can try using animations from the UE4 skeleton or from Manny himself, but I believe errors may occur.
However, retargeting is always useful.

Adding Animations to the Sequence

With your character added to the sequencer, simply add the desired animation to the character’s track. You can do this by dragging the animation directly onto the track or by using the “Add Animation” feature available in the sequence editor.

Repeat the same process to add facial animations if necessary. Facial animations can be added in the same way as body animations, by creating a new facial track and adding the corresponding animations.

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Physics

An interesting technique I used to bring the character to life, in addition to facial and body animations, was the application of physics. The Unreal Engine is very powerful in this aspect and allowed the physics to work very effectively.

In this project, I employed three types of physics: one for the grenade, another for the cloth (applied to the clothing and the fallen fabric of the sword), and a body physics, which was applied to the character’s breasts.

This combination of techniques provided additional realism to the movement. I will leave a link to the documentation of each type of physics used at the end of the article.

Physics Constraints

This type of physics was applied to the grenade in my project.

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Chaos Cloth: I applied this physics to the blouse, boot laces, and fabric attached to the sword.

A_ChaosCloth

Spring Controller: This is the component responsible for applying physics to the breasts. The controllers are added directly to the character’s Animation Blueprint (animBP) and configured by bones, meaning you configure them by choosing a specific bone from the character’s skeleton.

A_Spring-Controller

Here’s another demonstration showcasing all the applied physics in action: [YouTube link]

VFX/Material for the Grenade and Arm

For the material used on the grenade and arm info screen, I sought an animated representation designed to dynamically reflect the current status.

A_VFX

To begin, I created a texture using RGB as a mask, with each color representing a specific part of the UI.

Not only does this approach consolidate multiple elements into a single texture, but it also optimizes performance and greatly simplifies the material creation process.

The material is constructed as if it were made in layers, with three layers utilizing the RGB channels and one for the background itself, providing better control. Knowing this, each layer has its respective distortion and offset parameters so that the desired effect functions properly.

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Below, I show each set of nodes separately.

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Note

To facilitate understanding, I chose to provide the material in case you want to experiment with it.

With all the settings and parameters adjusted, I created an instanced material to have full control over the material, making the setup easier and more flexible.

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Conclusion

Throughout this article, we’ve explored various aspects of the creation and presentation process of a 3D character, from rigging to the application of visual effects and physics.

We began by addressing rigging, then discussed facial and body animation, followed by the exploration of specific VFX materials, which add impressive visual details to the character and applied physics, which provides natural and convincing movements.

Through these processes, we were able to create an engaging and realistic presentation of the character, highlighting her personality and unique characteristics.

By setting aside the technical details and focusing on the final results, I hope you are inspired to further explore the exciting challenges and possibilities of the 3D modeling world.