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Chupa: A New Approach to 3D Avatars

Chupa simplifies creating personalized 3D avatars using images and text inputs.

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Creating 3D digital humans, or avatars, is important in fields like gaming, animation, and virtual reality. These avatars help users immerse themselves in digital spaces. However, making high-quality avatars usually requires skilled 3D artists and a lot of time.

Recent advances in technology have made it possible to create better images, but making 3D humans has been difficult because of the variety in human shapes, poses, and details. To improve this, we introduce a new method called Chupa. This method uses modern techniques to create realistic digital humans more easily and quickly.

Overview of Chupa

Chupa is a system designed to generate realistic 3D humans from images. It breaks the process into smaller steps, first focusing on creating detailed 2D images of the front and back of a human. These images are called Normal Maps, which show details like wrinkles and clothing textures.

Once we create these normal maps, we use them to shape a 3D Model of a human. This model can change to match different poses and appearances. Chupa can also take text descriptions to influence how the avatar looks, allowing users to easily create their own personalized avatars.

Importance of 3D Digital Avatars

3D avatars are essential for many industries. In gaming, players want characters that look and feel real. In animation and virtual reality, high-quality avatars help create engaging experiences.

Creating these avatars is typically a time-consuming task requiring talented artists. Recent tech advancements have made image generation easier, but applying this to 3D humans remains a challenge. Most methods struggle with getting every detail right because they often rely on limited data and can miss important features.

Challenges in 3D Human Generation

Creating a realistic 3D human requires accounting for various aspects such as identity, pose, and fine details. Traditional methods generally focus on either creating images or shapes but not both at the same time.

While some approaches have tried to generate 3D human models, they often produce unsatisfactory results regarding detail and realism. A major issue is the difficulty in gathering enough realistic data for training, which often leads to models that don't perform well when generating new poses or details.

Chupa's Methodology

Chupa tackles these problems by focusing on two main steps: generating 2D normal maps and using them to create a 3D human model. This two-step process makes it easier to achieve the necessary level of detail needed in 3D avatars.

Normal Map Generation

The first part of Chupa involves creating normal maps for both the front and back of a human. These maps provide detailed information about the figure's surface, like where light hits and how shadows fall. By using a method that combines the power of image generation with a focus on 3D Reconstruction, Chupa can create consistent and detailed normal maps.

Once we have the normal maps, we can use them to create a realistic 3D model. This is achieved by adjusting an initial model to match the details in the normal maps. The process involves gradually Refining the 3D model to ensure it matches the normal maps as closely as possible.

3D Reconstruction

After creating the normal maps, we use them to reshape an initial 3D model called SMPL-X. This model serves as a strong base, providing a consistent starting point for creating the final digital human.

The goal during reconstruction is to fine-tune the model so it accurately represents detailed features from the normal maps. This involves a process where we compare the generated normal maps with those from the 3D model and make necessary adjustments.

By continuously adjusting and optimizing the model, we ensure that it not only looks realistic but also maintains the correct proportions and details.

Refining Details

Chupa includes an additional step to refine both body and facial features. This involves rendering the normal maps from various angles to capture more detail. Following this, we can adjust the norms based on these views, ensuring that the final avatar looks good from all perspectives.

The refinement process helps eliminate any artifacts or unnatural appearances that may have arisen during earlier steps. This results in a more polished and realistic avatar, ready for use.

Incorporating Text Input

A unique feature of Chupa is its ability to take text descriptions as input. By integrating a text-to-image model, users can specify certain characteristics, like gender or clothing style, and generate avatars that match those descriptions.

This process enhances the user experience by making it easier to create personalized avatars without needing extensive knowledge of 3D modeling. Users can describe what they want, and Chupa generates a corresponding 3D model that fits the description.

Evaluating Chupa

To measure how well Chupa performs, we've carried out tests comparing it to previous methods. We look at both quantitative metrics, which provide numerical data, and qualitative feedback from users, who evaluate the visual quality of the generated avatars.

In tests involving datasets of various human identities, Chupa consistently produced better results than earlier methods. It showed lower scores in image quality metrics, which indicates that the avatars generated are not only visually appealing but also realistic.

User Preferences

We also conducted user studies to determine which avatars people found more appealing. Participants were asked to compare avatars generated by Chupa with those from previous methods. Most users preferred the avatars created by Chupa for both full-body and facial images.

These results highlight Chupa's effectiveness in meeting user expectations for realism and detail in 3D avatars.

Future Directions

While Chupa shows great promise, there is still room for improvement. Future work could focus on creating avatars with even more realistic textures and features.

Additionally, integrating motion and animation capabilities into the avatars could further enhance their usefulness in various applications, such as gaming and virtual reality experiences.

Conclusion

Chupa represents a significant step forward in the creation of 3D digital humans. By simplifying the process and allowing for the generation of personalized avatars from both images and text, Chupa brings a new level of accessibility to 3D character creation.

This system not only streamlines the workflow for creating engaging digital avatars but also opens doors for a wider range of applications across different industries. As technology continues to evolve, methods like Chupa will likely play a leading role in how we create and interact with digital representations of ourselves.

Original Source

Title: Chupa: Carving 3D Clothed Humans from Skinned Shape Priors using 2D Diffusion Probabilistic Models

Abstract: We propose a 3D generation pipeline that uses diffusion models to generate realistic human digital avatars. Due to the wide variety of human identities, poses, and stochastic details, the generation of 3D human meshes has been a challenging problem. To address this, we decompose the problem into 2D normal map generation and normal map-based 3D reconstruction. Specifically, we first simultaneously generate realistic normal maps for the front and backside of a clothed human, dubbed dual normal maps, using a pose-conditional diffusion model. For 3D reconstruction, we "carve" the prior SMPL-X mesh to a detailed 3D mesh according to the normal maps through mesh optimization. To further enhance the high-frequency details, we present a diffusion resampling scheme on both body and facial regions, thus encouraging the generation of realistic digital avatars. We also seamlessly incorporate a recent text-to-image diffusion model to support text-based human identity control. Our method, namely, Chupa, is capable of generating realistic 3D clothed humans with better perceptual quality and identity variety.

Authors: Byungjun Kim, Patrick Kwon, Kwangho Lee, Myunggi Lee, Sookwan Han, Daesik Kim, Hanbyul Joo

Last Update: 2023-09-15 00:00:00

Language: English

Source URL: https://arxiv.org/abs/2305.11870

Source PDF: https://arxiv.org/pdf/2305.11870

Licence: https://creativecommons.org/licenses/by/4.0/

Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.

Thank you to arxiv for use of its open access interoperability.

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