Procedural characters interacting with the environment. Work of ESR 3, Rafael Andrés Blanco Guerra (UPC).
Social activity which took place in Saint Malo, during the 2nd training workshop in Rennes, France.
Photo of the ESRs’ presentations, during the 3rd training workshop in Barcelona, Spain.
Virtual characters for realistic scenarios A variety of skills are required to develop realistic virtual characters. The aim of the CLIPE project is to train the next generation of researchers in virtual humans and make more realistic virtual characters that are capable of interacting naturally with humans, as Yiorgos Chrysanthou, Nuria Pelechano, Nefeli Andreou and Rafael Blanco explain. The market for augmented reality (AR) and virtual reality (VR) technologies continues to grow, with people across the world playing games that bridge the real and virtual worlds, a trend which demands the development of sophisticated and realistic virtual characters. There are also many applications in education, architecture, medicine and engineering that require immersive collaborative VR experiences populated with virtual characters. This issue lies at the heart of the EU-funded CLIPE project, an initiative bringing together academic and commercial partners from across Europe to provide training to early stage researchers (ESRs). “We´re creating the technology to generate digital characters. We’re trying to make them more realistic and to improve the way that they interact with humans,” says Nuria Pelechano, an Associate Professor at UPC in Barcelona, a member of the CLIPE team. The primary focus here is on the behaviour and animation of the virtual characters, rather than their visual appearance. “We’re interested in developing virtual characters that can populate virtual environments or move around us, within an environment populated by physical agents, in a way that is as human-like as possible,” explains Professor Pelechano.
CLIPE project Making the characters behave in a more realistic way is central to establishing trust between a human and a virtual character. If virtual characters don’t have naturallooking facial expressions then a human might struggle to trust them, which hinders interaction. “Then it’s hard work to establish communication between a physical agent
46
and a virtual character,” points out Professor Pelechano. Making these characters more realistic is a correspondingly important aim in the project. “We develop algorithms, evaluate them, and identify what is missing – we look at what works and what doesn’t. Then we can go back and improve the algorithm,” says Yiorgos Chrysanthou, Professor of Computer Science at the University of Cyprus, coordinator of CLIPE. “We are working to improve the animations of different characters, when immersed in virtual reality worlds. It may be that there are trade-offs, where we have to assess what’s more important in terms of the realism of the virtual character and
with a large number of humans, how can you do that more easily so that you don’t need to spend lots of time minutely specifying each person and each aspect of their behaviour? So we are also looking at procedural authoring of crowds for example,” he says. “The state-ofthe-art in virtual humans is quite advanced, but this is one of the areas that could be improved further.” A major challenge here is that the behaviour of a group of individuals can be difficult to simulate. While somebody may have left their home with a clear agenda, those plans are subject to change at any point. “An individual might meet somebody in the street and start
We’re developing the technology, the digital characters. We’re trying to make them more realistic and to improve the way that they interact with humans. interactivity, for example between how much to use pre-captured movements or computer generated ones.” The ideal scenario would of course be to fix all of the different aspects at the same time, but typically there are trade-offs involved and decisions have to be made. Rather than simply deciding what specific features to focus on, Professor Chrysanthou says perceptual data is used to identify priorities. “It might be that we particularly want to get the facial expressions right,” he outlines. Beyond making the virtual characters look more realistic and conveying facial expressions and emotions, Professor Chrysanthou and his colleagues in the project also work on the ease of defining certain things. “For example if you want to populate a large environment
talking about the major topic of the day, or maybe they’ve forgotten something at home, and decide to turn around abruptly. That kind of behaviour can be difficult to incorporate in a virtual crowd,” explains Professor Pelechano. The movement of a crowd also varies according to the situation, an issue which Professor Pelechano is taking into account in her research. “We have sophisticated methods to learn about the movement of a crowd and to copy it,” she says. “A crowd on a busy subway station for example doesn’t behave in the same way as a crowd in a shopping centre, or a crowd in a pub. We can try to build stronger foundations so that we can then extrapolate to different situations.” This would make it much easier to populate an environment with virtual characters,
EU Research
giving the appearance of a real crowd without the need to laboriously create each individual within it. This would benefit many different application domains, helping accelerate development. “It would help the game industry, the movie industry as well as simulation and training industries,” says Professor Pelechano. This would also make virtual characters more accessible to people who maybe don’t have a technical background or limitless resources to spend on animation. “We are trying to combine different techniques that can make the process of populating a different environment easier for the general public,” continues Professor Pelechano. “This is also important with the concept of the metaverse. People are working to create normal surroundings for the metaverse, like cities, houses and environmental features, but you will also want to see people in there.” Indicative photo that was taken during the visit to Immersia labs, as part of the 2nd training workshop activities that took place at Rennes, France.
www.euresearcher.com
Training The ESRs in the project gain a grounding in a wide range of different techniques, equipping them with the skills required to develop realistic virtual characters, for which demand is growing. There are several industrial partners involved in the project, testament to wider interest. “There is the special-effects industry for movies, the games industry and also the online retail industry, where there is interest in using virtual characters for trying on clothes. In that latter case, appearance might be more important than behaviour,” outlines Professor Pelechano. There are 15 ESRs in CLIPE working on different research projects, around the core aim of improving the simulation and animation of virtual characters. “The focus is on enhancing the realism of virtual characters in urban, populated environments,” says Professor Pelechano. “The project is not about Photo taken of STAR presentation at the Eurographics 2022 conference in Reims (FR), where some of our CLIPE students had the opportunity to present their work.
building one specific application or developing a specific research idea. Rather it’s about training researchers, who could be leaders in the industry in the future.” This is not just about technical knowledge, but also ‘soft’ skills like grant writing. The aim is to equip the students with the broad range of skills they will need to keep pushing forward development as their careers progress. “We aim to help prepare students for their future careers, whether that’s in academia or industry,” says Professor Pelechano. With many of the students entering the final year of their PhDs, Professor Chrysanthou hopes to see many more research papers published over the coming years, which could then lead on to commercial development. “It may be that some of the ideas have a lot of commercial potential. We’re also going to hold some further training workshops,” he continues. Indicative photo that was taken during the visit to Immersia labs, as part of the 2nd training workshop activities that took place at Rennes, France.
47