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Motion Capture: A Guide to Motion Capture Technology

What is Motion Capture

What is Motion Capture?

Motion capture, often abbreviated as MoCap, is the technology and process by which motion of people or objects is digitally captured and reproduced in a virtual environment. This technology has gained importance in many industries in recent years.

Motion capture applications: More than just entertainment

  • Film and televisionIn the film and television industry, MoCap is used to create realistic movements for CGI characters. Well-known examples are Gollum from "Lord of the Rings" or the Na'vi from "Avatar".
  • Video games: In game development, MoCap helps create lifelike movements for game characters that provide a more immersive experience for the player.
  • Virtual Reality: In VR, motion capture data is used to create realistic avatars in real time.
  • Health and sport: In the health field, MoCap is used to analyze human gait and rehabilitate patients after injuries. Athletes also use it to refine their technique.
  • Military: Together with Virtual Reality, MoCap enables realistic simulations for training scenarios.
 
 

Various motion capture processes: 

An overview

 
    • Optical - passive: One of the oldest and still widely used forms of motion capture is the marker-based method. This involves placing special markers, usually reflective spheres or anchor points, on the performer's body. Cameras in the recording studio track these markers to capture precise motion data. Marker-based motion capture provides precise capture of motion and enables detailed recreation of human anatomy. However, it requires markers to be placed on the body, which takes time and effort and can limit the actor's freedom of movement.
    • Optical - active: Here, small lights emit signals that are recorded by cameras. Some advanced motion capture systems like the one from OptiTrack use this technique.
    • Ki solutions with video analysis / without markerModern AI algorithms and special motion capture software can now capture movements directly from video recordings without the need for markers. This requires either several simultaneously recorded videos of a movement or even just one view. The more cameras that record the scene simultaneously, the more accurately the artificial intelligence can extract motion data from the videos. We can assume that this technology will become more important in the future as AI solutions are currently developing rapidly. Examples of products in this area are MoveAI https://www.move.ai/ or Radical. Rokoko, who are actually known for motion capture suits, have also provided an AI solution for their paying customers.
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Motion capture
Motion capture with IMU technology
    • Inertial sensors - IMUs: This method uses sensors attached to the body that record movements in real time. Products like Rokoko's SmartSuit Pro and Perception Neuron from Noitom are popular examples of this technology. This inertial motion capture technology offers a wireless and wearable solution, as no additional cameras or markers are required. Users can simply don the suits and record real-time motion data, which can then be used to create animations or control virtual characters. One potential drawback of IMUs (inertial measurement units) in motion capture is their limited accuracy over extended use. IMUs are based on the capture of acceleration and rotation and can therefore be prone to drift, which can lead to a gradual accumulation of errors. This can cause the captured motion data to become inaccurate over time, requiring periodic calibration or correction. IMU based motion capture systems are e.g. Percetion neuron and Smart Suit from Rococo

 

Benefits and challenges:

Advantages of Motion Capture:

  • Low latency: Motion capture enables instant conversion of real motion into digital motion data.
  • Accuracy: MoCap provides accurate and realistic data depending on the equipment.
  • Motion capture drastically reduces the cost and time required to create character animations.

Motion capture disadvantages:

  • Most motion capture technologies require specialized software and hardware: Capturing and processing MoCap data usually requires specialized equipment and software.
  • Costs: High-quality MoCap systems can be expensive. Inexpensive systems are usually much less precise than the more expensive systems used in large film productions.
 

Step by step: How motion capture works

Preparation: The actors or objects are equipped with the necessary markers or sensors.

Recording: The movements are recorded with special cameras or sensors.

Data processingThe recorded motion data is then converted into a digital format that can be used in software such as Maya, 3dsmax or Blender. Most of the time it is still necessary to remove errors and inaccuracies that occurred during the capture process. This process can be quite lengthy depending on the quality of the source data. This process is called "cleaning". Once the data has been cleaned, it can be loaded onto a 3D charkter model in the selected 3D animation software.  

 

Motion capture investment: What does it really cost?

The cost of motion capture can vary depending on the quality and complexity of the system required. Entry-level systems such as Rokoko and Perception Neuron can be available for around 3000 euros, while professional systems can cost six-figure sums.

The quality of low-priced systems is constantly improving, so that impressive results are possible even with a 3000 Euro system.

AI motion capture portals such as Radical which generate mocap data from videos. 

 

The history of motion capture technology

The idea of motion capture dates back to the 1920s, when the technology was first used in the film industry. However, motion capture was very limited at the time and could only capture simple movements. In the 1970s, the first marker-based motion capture systems were developed, which made it possible to capture motion more accurately. Today, there are several types of motion capture systems, including optical, magnetic, and inertial.

Facial Motion Capture aka Performance Capture:

In addition to capturing body movements, a character's facial expressions and gestures are also very important. Facial Motion Capture focuses specifically on recording and transmitting facial movements. Either marker-based or markerless methods are used to capture the smallest facial expressions and facial expressions. A notable example of the power of face-capturing is the portrayal of Gollum in the "Lord of the Rings" film trilogy. The character's subtle facial features and emotions were rendered realistically and believably, made possible in significant part by face-capturing technology. Actor Andy Serkis, who portrayed Gollum, provided not only the voice and physical movements for the character, but also the facial movements. However, there are also increasingly affordable face capture solutions, most of which only use an iPhone to record facial movements. For example, iClone, Rococo and Unreal Engine's Metahuman Animator. So facecapture has become a real option even for small studios to create more vivid 3d characters.

Tips for successful motion capture sessions

A successful motion capture session requires careful planning and preparation, as well as clear communication with the actors or animals. It is important that actors wear comfortable clothing and do not wear accessories that could interfere with motion capture. The motion capture session should also take place in a well-lit room for best results. Perform calibration and test runs before starting the actual capture. Check the functionality of the equipment and ensure that motion is captured and transmitted correctly.

Popular motion capture software and tools

There are many motion capture software and tools on the market. Some of the most popular are Autodesk MotionBuilder, Rococo, Iclone, Vicon, OptiTrack and Xsens. These software and tools offer a wide range of functions to create precise animations and visual effects.

Case studies of successful motion capture content

There have been many successful motion capture content created, in various industries. The film industry uses motion capture to create realistic animations of animals and monsters. It is also used in video game development to create realistic animations of characters and movements of athletes. In advertising, motion capture has been used to bring products to life.

We from Design4real use motion capture in various projects, such as the VR Diversity Workshop Moment times, or also the WebAR Halder Hammer Showcasewhere we used technology to give the 3D characters lifelike animations.

 

The future of motion capture technology

Motion capture is a rapidly evolving technology that is expanding to more and more industries. In the future, the technology will become more powerful and capable of creating even more realistic animations and visual effects. We believe that artificial intelligence will revolutionize this technology and that in the future, special hardware for mocap recording will hardly be brewed. Move.Ai already shows how powerful and simple artificial intelligence mocap solutions can be. In the future, we will probably be able to record motion capture at a high level simply using a mobile phone. The conversion into motion data will be handled in the cloud with the help of artificial intelligence. 

Conclusion

Motion capture technology has changed the way we create animations of 3D characters. By capturing motion, realistic animations can be created with manageable effort. The XR Agency Design4real is the right partner for appealing character animations with motion capture and face capture.