The Ethereal Engine combines fitness with gaming and VR. By using two actuated armatures and foot platforms, the machine can provide users with force feedback while they enjoy a multitude of simulations that do not feel like a workout at all. Regular physical exercise is very difficult for many people. This can lead to poor health and increased associated risks for the body and the mind. The Ethereal Engine offers a solution: With exhilarating and exhausting experiences, users can fly with an ornithopter through magical landscapes or paddle through alien waters on foreign planets. Invented and under development by the company Ethereal Matter in the US, the project spans multiple countries, TU Delft faculties and student projects. In this graduation project, the next design of the frame for this very machine is proposed, with a special focus on user perception on the one hand, and engineering-related topics on the other. The project commences with user research into spatial perception emotion and the experience of transitioning from and to VR. Practical limitations such as maximum carrying weights, door and truck dimensions, and intended use cases result in manufacturability, transport, assembly and durability requirements. By using and adapting generative design tools (McNeel’s Rhino, Grasshopper and the plugin Karamba3D) for structural spaceframe design, a satisfying solution is found for the main structure. This basic structure is then designed around and iterated upon using VR reality tools like Gravity Sketch to create frame layouts that feel comfortable and safe. Constant iteration and testing in VR leads to a modular frame layout that allows multiple machines to be connected, but also up or downgraded to more or less extensive versions. Features like a mirror, a space to safely store personal belongings, and integrated lighting are proposed. The machine has fabric for the outside covering which is customizable, affordable and easy to transport. The final design includes a seat in the back with an attached screen for outside viewers to see what is happening in VR. Added interactive elements could lead to whole new interactions between people in the real world with the people in VR. Accompanying the project was the construction and assembly of a partial prototype of the frame and one armature in the Dreamhall of the TU Delft. It is upon the next students to finalise the second Ethereal Engine in the world and perform the (first?) intercontinental handshake through VR.

Providing a bodily injury-free experience might be a promising opportunity for the adoption of VR and force feedback-based equipment in a gym context. Nevertheless, it is still uncertain how these systems could compromise the users’ physical state and how they should react a posteriori.

This Graduation project begins with the exploration of the bodily injury risks associated with the Ethereal Engine, an ultimate VR-based equipment that seeks a revolution in the fitness industry. Resulting in four different clusters -collision, posture, balance loss and long-term exposure-related risks-, a study on the current market-ready technologies that could minimize these risks is performed together with an assessment on how safety can be boosted while keeping the experience’s engagement.

Thanks to the research, posture evaluation is selected as the challenge with a differential potential over the rest to bring Ethereal Engine to the next level, providing an experience in which bodily injury risks could be reduced, motivating users to adopt better postural habits when working out. Right after, a design vision is formulated, emphasizing the need for inspiring users to self-correct their posture instead of imposing rules in order to avoid possible immersion breakages.

In this context, three concepts are proposed, which present different feedback alternatives that vary in terms of explicitness, immediacy, and strictness. However, a priori there is no clear answer on which of these alternatives could most positively affect the experience. To overcome the knowledge gap an experiment that not only assesses the performance of the 16 participants but also their perception of the understandability, usefulness, performance, posture correction, general engagement, confusion and criticism of the feedback is conducted. During three different experiments where different feedback alternatives are assessed -immediate visual clues, statistics after certain repetitions, and immediate pop-up messages- participants are asked to perform 10 squats while lifting a water jug and receiving different scores depending on its displacement.

In order to do so, a partial prototype that allows for the first time to experience certain functionalities of the Ethereal Engine is developed. These functions are: a) a hybrid MoCap system that merges a Oculus Quest headset with a multi-camera-based skeletal tracking system -named MoCapForAll-. ; b) a calibration process that adjusts the range of motion according to the participant’s height; and, c) a demo game that enables a more intense workout while keeping track of your posture while squatting.

After discussing the results, including a calibration process that enables fair competitiveness and feedback at three different levels to communicate diverse information are spotted as desired features to include in the Ethereal Engine. Through these recommendations a virtual trainer that inspires users to self-correct their posture will be possible, and, subsequently, enabling a bodily injury-free experience.