CGI suits, often called motion capture or "mo-cap" suits, work by capturing the movements of an actor to create animation for computer-generated characters or objects.
Here's a breakdown of the process based on typical motion capture technology:
The Mechanics of Motion Capture Suits
At its core, the process involves translating real-world movement into digital data that a computer can use to animate a CGI model. This is achieved through specialized suits and camera systems.
- The Suit: A mo-cap actor wears a full-body suit. This suit is typically made of dark, form-fitting material to provide a clear background for tracking markers.
- The Tracking Dots: The suit is covered in small markers, often reflective spheres or lights, which are the "tracking dots" mentioned in the reference. These dots are strategically placed on the suit at key points corresponding to major joints (like elbows, knees, shoulders) and other important areas of the body.
- Mapping to the CGI Model: Each tracking dot corresponds to a specific point or bone in the computer-generated image (CGI) model of the character or object being animated. Think of the dots as digital pins holding the virtual skeleton together.
Capturing the Movement
The magic happens when specialized cameras record the actor's performance while wearing the suit.
- Camera Systems: A system of cameras is set up around the capture volume (the area where the actor performs). These cameras emit infrared light (for reflective markers) or detect light emitted by active markers.
- Recording Positions: The cameras record the position of the dots in 3D space as the actor moves. By tracking where each dot is located at any given moment, the system knows the exact posture and position of the actor.
- Tracking Distances: Crucially, the system also records the changing distances between them. This data helps the software understand the relationships and movements between different parts of the body. For example, how the distance between the elbow and wrist markers changes as an arm bends.
Building the Animation Framework
Once the data from the cameras is collected, it's processed by specialized software.
- Data Processing: The software uses the recorded positions and distances of the dots over time.
- Creating the Framework: This data builds a framework to base the animation on. The movement of the tracking dots directly dictates the movement of the corresponding points on the CGI model's skeleton or rig.
- Applying to the Model: The movement data is then applied to the CGI character. The character's virtual joints and limbs follow the path of the actor's real-world movements, effectively transferring the performance to the digital character.
In summary, CGI or mo-cap suits enable the capture of human or animal movement using tracking markers and cameras, which then translate this data into animation for digital characters by tracking the markers' positions and the changing distances between them.
