After you have calibrated your Vicon cameras, you are ready to create and calibrate subjects and any props that you need.
To create and calibrate subjects and props, complete the following procedures as required, depending on whether you are using clusters and/or props:
In addition to the following information, see also the Vicon video , which demonstrates how to place markers on a performer and how to calibrate a subject using a T-pose and ROM. ‌
Add clusters to the datastore (optional step)
To help Shogun Live in booting the labeling setup and to uniquely identify performers, you can use clusters. Clusters are particularly useful in scenes with multiple performers.
Place one or more labeling clusters on each performer, with each cluster containing four or more markers. Ensure clusters are unique by varying the position of the markers in each cluster.
Before you can use the clusters for motion capture, you must add them to the Shogun Live datastore, to enable Shogun Live to recognize them.
To add clusters to the datastore:
- Place the cluster(s) in the volume and ensure all the markers are visible to the cameras.
- On the Subject Calibration tab, in the Clusters section, you can specify the folder to which to save clusters.
You can either use the default folder (C:\Users\Public\Documents\Vicon\Clusters), or to change it, click Manage Clusters, click Browse to locate the required folder, click Select Folder and in the Clusters dialog box, click Close.
- In the 3D Scene, ALT+drag to select all the markers for a cluster.
- In the Clusters section, click the Create Cluster button.
A cluster is created from the selected markers.
If you need to rename or delete clusters, click Manage Clusters and in the Clusters dialog box, right-click the required cluster and then click the relevant option.
After you have saved clusters, you can import them into subsequent takes by clicking Manage Clusters and then Import.
Place markers on a performer
To place markers on a performer:
- Place the standard 53 Vicon markers on the performer(s), as shown in the following illustrations, which also show the placement of a cluster. (It is assumed that you are using one of Shogun’s default labeling templates. If you are using a different template, please contact Vicon Support.)
If you're using side waist markers to handle issues such as marker occlusion (for example, if the front waist marker is likely to be occluded due to a performer's hands obstructing it or the performer bending forwards), place the waist marker(s) at the sides of the performer's waist:
Ensure that the foot markers are placed so that the toe marker is as far forward as possible on the foot while still facing upward. Also ensure that the three other markers (the heel marker and the two markers on either side of the front of the foot) are in the same plane, and are as low (ie near to the floor), as possible.
- If you're using finger markers, place the additional finger markers on the hands.
Follow these guidelines to ensure that the finger markers produce an accurate solve:
- Wrists: The wrist marker placement is important because the foundation of a good finger solve is a correctly solved wrist. Place the wrist markers on either side of the wrist so that both markers are the same distance down the arm and as close to the joint center as possible.
- Hands: Place the hand markers just before the knuckle of the index and pinky finger.
- Fingers: For three-finger setups, place a marker just before the first joint of the index, pinky, and thumb, so that it is not affected by rotation of the second joint.
The following images show placement of the wrist, hand, and finger markers in a three-finger setup:
If you're using clusters (see Add clusters to the Shogun Live datastore), if you haven't already done so, place them on the performer(s). Normally, a good location for the cluster is on the torso, but not too close to other markers. This can be on the front, as shown below, or on the back, as shown in the illustrations in Step 1.
To perform live subject calibration:
- To give the clearest view of the subject, at the top of the 3D Scene view, click View Settings, then clear Cameras, select Custom and ensure that Solving Subject and Skin are selected (in addition to any other options that you may want to use).
- On the Subject Calibration tab, in the Name field, enter a name for the new subject.
- In the Subjects section, choose the appropriate Labeling Template and Solving Template for your subject.
If you are using side waist markers and/or finger markers, make sure you choose the templates that include side waist markers and/or fingers (indicated by their names).
- From the Skin list, select the mesh that is to be used for the solving skeleton.
- Have the performer wearing the correct marker set (see Place markers on a performer) enter the volume and stand in a T-pose.
If you are using finger markers, pay extra attention to the pose of the hands and fingers.
- The wrists are straight, not bent to either side or up or down. The palm is parallel to the floor.
- The fingers are straight, with a natural spread, and no bend.
- The thumb is held tight against the index finger. When viewed from the top, ensure that the thumb and the fingers all point in the same direction.
- Click Create Subject.
On the menu bar, above the workspace, Subject Calibration Active and a flashing red circle is displayed.
In the 3D Scene view, the markers are labeled, and the labeling and solving skeleton is displayed.
- Visually check that all the markers have been labeled and everything looks OK.
- When you have checked that everything looks OK, on the Camera Calibration tab, click Accept T-Pose.
- Get the performer to perform a ROM (Range Of Motion) that includes all the required movement.
If you are using finger markers, ensure the performer completes the appropriate hand and finger movements, and include bending and spreading the fingers as well as poses of the hand that will be useful for checking the accuracy of the labeling.
When the ROM is complete, click Stop Calibrating.
In the 3D Scene, you can see the mesh and solving skeleton of the subject (if you need to change the display, at the top left of the workspace, click View Settings, select Custom and choose the required options). In the Subject panel, a subject with the name you supplied in Step 2 above is displayed, together with nodes representing its markers, segments and skin.
To change a skin base color and highlight color, in the Subject panel, right-click the Skin node. The skin colors are saved in the .mcp file when you exit Shogun Live.
The subject is now fully calibrated and can be used in captures as required.
Live occlusion-fixing occurs by default. This ensures the skeleton continues to behave correctly while markers are occluded. To ensure occlusion fixing is displayed, in the View Settings, select Custom, and ensure Solving Subject, Missing Markers and Skin are selected. Occlusion fixing is indicated by the red color and is also visible when X-Ray is selected.
To turn off occlusion fixing, at the top of the Processing panel, click Show Advanced and in the General section, clear Occlusion Fixing.
In Shogun Live, you can create simple, single-segment (and therefore rigid) props. A minimum of four markers is recommended for each prop.
When placing markers, be sure to:
Place the markers across the prop object to reach the extremities as far as possible.
Avoid placing markers in a straight line and/or on the same plane
Avoid placing markers symmetrically
Prevent marker swaps by avoiding placing prop markers too close to the hands or where the actor will interact with the prop.
For example, if a performer will interact with a prop, place markers at the extremities of the prop, but not directly in the location where the interaction occurs, as shown below, where a performer holds a sword:
To create a single-segment prop:
- Ensure the markers are positioned on the prop as described above.
- Place the prop in the volume.
- On the Settings menu, click Show Preferences (or press SHIFT+P).
- In the Preferences dialog box, on the User Preferences tab, ensure that the Props folder is as required, or if not, click Browse to specify the appropriate folder.
- In the 3D Scene, select a minimum of four reconstructed markers. To ensure that Shogun Live places the bone logically within the prop, select (CTRL+click) the markers in the following order:
- The first selected marker defines the origin (base) of the prop bone.
- The second selected marker defines the end of the prop bone.
- Any other markers can be selected in any order.
- On the Subject Calibration tab, in the Props section, enter a name for the prop and click Create Prop.
A single-segment prop is created from the selected markers and appears in the 3D Scene in the orientation defined by the order in which you selected the markers in the previous step.
The prop is displayed as a node in the Subjects tree on the left of the Shogun Live window, under the Props node.
The prop's .mcp file is saved to the location specified in step 2 above.
To save or remove a prop from the current scene, in the Subjects tree, right-click the prop and then click the relevant option.
After you have saved props, you can import them into subsequent takes as required.
Note that in addition to creating simple, single-segment props, you can also import both simple props and more complex, multi-segment props by clicking the Import Props button at the top of the Subject panel: