Whether live or offline there is a great range of potential applications for multi-actor sessions.
To achieve the best Multi Actor results we must overcome the challenge of a shared global position between all actors. This Global position can be broken down into two parts, Aligning the Origin (Ctrl+0) point of both avatars and Aligning the Heading (Ctrl+Alt+A) of both avatars.
- ALIGNING ORIGIN POINT
- ALIGNING HEADING
- POSITIONAL AIDING
Setting both Origin Point and Heading within MVN
Both settings are located Tasks in the Task bar. For more information watch the video on this functionality HERE.
ALIGNING ORIGIN POINT
To start we will look at two ways to align the actors origin point. Which method you use will depend on a number of factors such as the recording environment you are in as well as the number of actors in your recording.
The Origin point is set upon applying a calibration and is set to where the heel of the actors right foot is placed at the time. This can also be reset to where the actors standing at any time with the button ''Move Character to Origin'' (Ctrl+0), this will move the origin point to wherever the actors right heel is now placed during the live session.
(Heel to Heel Example)
Origin Method 01 ''Heel to Heel''
First have both actors stand in a neutral N-Pose back to back with the back of their right heels touching. Once both actors are holding this pose and the heels are aligned as best as possible (middle of heel to middle of heel) go to MVN and click ''Move Character to Origin''(Ctrl+0) with both connected suits selected in the hardware setup window.
This should snap both avatars to the same origin point in MVN. Don't worry if the avatars are facing the wrong direction, this will be fixed in the Heading Alignment stage.
(Marked Point Example)
Origin Method 02 ''Marked Point''
In this method we will mark the ground we we wish for origin point to be for all actors. Initially get your first actor to stand in N-Pose and mark a rectangle around their right foot. Add an additional mark where the middle of their heel is to help align the other actors. Once they are in position and the marking are made select only their avatar in MVNs hardware setup window and click on Origin Reset.
Next have the second actor stand in N-Pose aligning there stance with the previously marked position (most importantly lining up there right foot as close to the first actors) and click Origin Reset once your happy with their stance. Make sure to only select the avatar who is standing at the Marked Point, if other suits are also selected there origin point will be incorrectly set.
Do the same for any additional suits always using the marked position. While this is a slower way of setting the Origin it will be much easier to handle 3+ actors in one session than the Heel to Heel method.
(Shoulder to Shoulder Example)
Heading Method 01 ''Shoulder to Shoulder''
Have both actors stand shoulder in a neutral N-Pose. Make sure both actors are facing in the same direction as closely as possible. It may help to use a ruler or tape as a guide for this. Once both actors look to be properly aligned in N-Pose go to MVN and select ''Axis Reset''(Ctrl+Alt+A). Make sure both avatars are selected in Hardware Setup. This should snap both avatars in MVN to face the same direction.
(Back to wall Example)
Heading Method 02 ''Back to Wall''
Get both actors to stand with their backs against a wall while standing in N-Pose. Use the wall to align the two actors heading as much as possible. Once both actors are standing facing the same direction select both avatars in MVNs hardware setup window and click ''Axis Reset'' (Ctrl+Alt+A).
To further improve absolute position of your actors Xsens offers a few solutions.
Using an antenna to connect with global satellites such as GPS you are able to process your data with this absolute positioning. While GNNS is very signal quality reliant the result will be a more consistent and accurate position throughout the recording session.
For more information on GNNS click the link HERE
Vive Tracker Integration
From MVN 2020 onwards Vive puck tracker data can be used within MVN. This gives an absolute global position for all actors wearing a tracker as well as more flexible object tracking.
For more information on using Vive pucks with MVN click the link HERE