This post introduces rotors as a practical alternative to quaternions and matrices for 3D rotations. It explains that rotors, like quaternions, represent rotations as a single action around an arbitrary axis, but offer a simpler, more intuitive geometric interpretation based on the concept of "geometric algebra." The author argues that rotors are easier to understand and implement, visually demonstrating their geometric meaning and providing clear code examples in Python. The post covers basic rotor operations like creating rotations from an axis and angle, composing rotations, and applying rotations to vectors, highlighting rotors' computational efficiency and stability.
Augurs is a demo showcasing a decentralized prediction market platform built on the Solana blockchain. It allows users to create and participate in prediction markets on various topics, using play money. The platform demonstrates features like creating binary (yes/no) markets, buying and selling shares representing outcomes, and visualizing probability distributions based on market activity. It aims to highlight the potential of decentralized prediction markets for aggregating information and forecasting future events in a transparent and trustless manner.
HN users discussed Augurs' demo, with several expressing skepticism about the claimed accuracy and generalizability of the model. Some questioned the choice of examples, suggesting they were cherry-picked and lacked complexity. Others pointed out potential biases in the training data and the inherent difficulty of accurately predicting geopolitical events. The lack of transparency regarding the model's inner workings and the limited scope of the demo also drew criticism. Some commenters expressed interest in the potential of such a system but emphasized the need for more rigorous evaluation and open-sourcing to build trust. A few users offered alternative approaches to geopolitical forecasting, including prediction markets and leveraging existing expert analysis.
Meta's Project Aria research kit consists of smart glasses and a wristband designed to gather first-person data like video, audio, eye-tracking, and location, which will be used to develop future AR glasses. This data is anonymized and used to train AI models that understand the real world, enabling features like seamless environmental interaction and intuitive interfaces. The research kit is not a consumer product and is only distributed to qualified researchers participating in specific studies. The project emphasizes privacy and responsible data collection, employing blurring and redaction techniques to protect bystanders' identities in the collected data.
Several Hacker News commenters express skepticism about Meta's Project Aria research kit, questioning the value of collecting such extensive data and the potential privacy implications. Some doubt the project's usefulness for AR development, suggesting that realistic scenarios are more valuable than vast amounts of "boring" data. Others raise concerns about data security and the possibility of misuse, drawing parallels to previous controversies surrounding Meta's data practices. A few commenters are more optimistic, seeing potential for advancements in AR and expressing interest in the technical details of the data collection process. Several also discuss the challenges of processing and making sense of such a massive dataset, and the limitations of relying solely on first-person visual data for understanding human behavior.
Researchers at Tokyo Tech developed a high-speed, robust face-tracking and projection mapping system. It uses a combination of infrared structured light and a high-speed projector to achieve precise and low-latency projection onto dynamically moving faces, even with rapid head movements and facial expressions. This allows for real-time augmented reality applications directly on the face, such as virtual makeup, emotional expression enhancement, and interactive facial performance. The system overcomes the limitations of traditional projection mapping by minimizing latency and maintaining accurate registration despite motion, opening possibilities for more compelling and responsive facial AR experiences.
HN commenters generally expressed interest in the high frame rate and low latency demonstrated in the face-tracking and projection mapping. Some questioned the practical applications beyond research and artistic performances, while others suggested uses like augmented reality, telepresence, and medical training. One commenter pointed out potential issues with flickering and resolution limitations, and another highlighted the impressive real-time performance given the computational demands. Several expressed excitement about the possibilities of combining this technology with other advancements in AR/VR and generative AI. A few questioned the claimed latency figures, wondering if they included projector latency.
Creating Augmented Reality (AR) experiences remains a complex and challenging process. The author, frustrated with the limitations of existing AR development tools, built their own visual editor called Ordinary. It aims to simplify the workflow for building location-based AR experiences by offering an intuitive interface for managing assets, defining interactions, and previewing the final product in real-time. Ordinary emphasizes collaborative editing, cloud-based project management, and a focus on location-anchored AR. The author believes this approach addresses the current pain points in AR development, making it more accessible and streamlined.
HN users generally praised the author's effort and agreed that AR development remains challenging, particularly with existing tools like Unity and RealityKit being cumbersome or limited. Several commenters highlighted the difficulty of previewing AR experiences during development, echoing the author's frustration. Some suggested exploring alternative libraries and frameworks like Godot or WebXR. The discussion also touched on the niche nature of specialized AR hardware and the potential benefits of web-based AR solutions. A few users questioned the project's long-term viability, citing the potential for Apple or another large player to release similar tools. Despite the challenges, the overall sentiment leaned towards encouragement for the author and acknowledgement of the need for better AR development tools.
Karl Guttag analyzes the newly announced "Halliday" AR glasses, skeptical of their claimed capabilities. He argues that the demonstrated "AI features" like real-time language translation and object recognition are likely pre-programmed demos, not actual artificial intelligence. Guttag points to the lack of specific technical details, reliance on pre-recorded videos, and improbable battery life as evidence. He concludes that the Halliday glasses, while potentially impressive AR technology, are almost certainly overselling their AI integration and are more likely sophisticated augmented reality, not AI-powered, glasses.
HN commenters discuss the practicality and potential invasiveness of the Halliday glasses. Several express skepticism about the claimed battery life, especially given the purported onboard processing power. Others question the usefulness of constant AR overlays and raise privacy concerns related to facial recognition and data collection. Some suggest alternative approaches, like bone conduction audio and smaller, simpler displays for notifications. The closed-source nature of the project also draws criticism, with some arguing it limits community development and fosters distrust. Finally, the high price point is mentioned as a significant barrier to entry.
Summary of Comments ( 7 )
https://news.ycombinator.com/item?id=43234510
Hacker News users discussed the practicality and intuitiveness of using rotors for 3D rotations. Some found the rotor approach more elegant and easier to grasp than quaternions, especially appreciating the clear geometric interpretation and connection to bivectors. Others questioned the claimed advantages, arguing that quaternions remain the superior choice for performance and established library support. The potential benefits of rotors in areas like interpolation and avoiding gimbal lock were acknowledged, but some commenters felt the article didn't fully demonstrate these advantages convincingly. A few requested more comparative benchmarks or examples showcasing rotors' practical superiority in specific scenarios. The lack of widespread adoption and existing tooling for rotors was also raised as a barrier to entry.
The Hacker News post titled "Rotors: A practical introduction for 3D graphics (2023)" has generated a moderate discussion with several interesting comments. Many commenters praise the article for its clarity and insightful approach to explaining rotors.
One commenter appreciates the visual explanation of rotor interpolation, stating that it finally made the concept click for them. They highlight how the article demonstrates how rotors avoid gimbal lock, a common problem with other rotation representations like Euler angles. This comment emphasizes the practical value of the article for those struggling with 3D rotation concepts.
Another commenter points out the connection between rotors and quaternions, explaining that rotors are essentially a different way of looking at quaternions, specifically using a geometric algebra perspective. They delve a bit into the mathematical background, mentioning how rotors represent rotations as oriented arcs of great circles on a 3-sphere. This adds a layer of theoretical depth to the discussion, connecting the article's content to broader mathematical principles.
Further discussion revolves around the practical applications of rotors. One commenter mentions their use in game development, specifically for character animation and camera control. This highlights the real-world relevance of the topic and the potential benefits of using rotors in practical 3D graphics applications.
Another commenter expresses a preference for rotors over quaternions, arguing that they are easier to understand intuitively and visualize. They appreciate the geometric interpretation of rotations provided by rotors. This comment contributes to a small debate about the relative merits of rotors versus quaternions.
Finally, some commenters mention other resources for learning about rotors and geometric algebra, expanding the scope of the discussion and providing further avenues for exploration. They provide links and suggest books, giving interested readers more opportunities to deepen their understanding.
Overall, the comments section reflects a positive reception of the article, praising its clarity and practical approach to explaining rotors. The discussion touches upon the theoretical underpinnings of rotors, their practical applications, and their relationship to other rotation representations.