Importing Motion Capture Files
You can import motion capture information into XSI using either the Acclaim or Biovision file formats. Both of these file formats contain motion information captured with optical technology.
Once you have imported the mocap files into XSI, you can constrain the mocap rigs to your own rig, plot the mocap data, then transfer the resulting action sources from the mocap rig to your rig. See Transferring the Mocap Data to Your Rig for more information.
You can import a file saved in the Acclaim Skeleton (.asf) format with an accompanying Acclaim Motion Capture (.amc) file. You can import an ASF file along with one compatible AMC file.
Acclaim Skeleton files (ASF) contain information about the hierarchy and base pose of the skeleton. This information is used to create a skeleton hierarchy (nulls or bones) when imported into XSI. The animation for this skeleton is saved in an accompanying Acclaim Motion Capture (AMC) file.
ASF files are imported into XSI as models placed under the Scene_Root node. The model’s name is the same as the skeleton’s name. The model contains a hierarchy of nulls or bones that reflect the skeleton hierarchy described in the ASF file. The model also contains a base pose action in which the model is initially posed.
AMC Files
Acclaim Motion Capture (AMC) files contain keyframed animation (motion capture data) that can be applied to the skeleton hierarchy in a compatible ASF file.
AMC files are imported into XSI as an action with the AMC file’s name. You can choose to have this action automatically applied as an action clip in the animation mixer (see Setting Other Import Options).
To import Acclaim files into XSI
1. Choose File > Import > Acclaim File from the main menu. The Acclaim Import dialog box appears.
2. In the Skeleton File text box, specify the ASF file to be imported.
3. In the Motion File text box, specify the accompanying AMC file to be imported. This AMC file must be compatible with the ASF file you’re importing.
4. Select how you want to import the skeleton hierarchy—see Setting Up the Skeleton.
5. Select the other import options—see Setting Other Import Options.
6. Click OK to import the Acclaim files.
Biovision (BVH) files contain information about the hierarchy of the skeleton. This information is used to create a skeleton hierarchy (you can choose between nulls or bones) when imported into XSI.
BVH files also contain two actions: the base pose action and the motion action. The skeleton uses the base pose by default unless you choose to have the motion action automatically applied as an action clip in the animation mixer (see Setting Other Import Options).
Biovision files are imported into XSI as models and placed under the Scene_Root node. The model’s name is the same as the BVH file name.
To import a Biovision file into XSI
1. Choose File > Import > Biovision File from the main menu. The Biovision Import dialog box appears.
2. In the File Name text box, specify the BVH file to be imported.
3. Select how you want to import the skeleton hierarchy—see Setting Up the Skeleton.
4. Select the other import options—see Setting Other Import Options.
5. Click OK to import the Biovision file.
You can choose how you want the skeleton hierarchy to be created when you import it into XSI using the following options.
These options are the same for importing either Acclaim or Biovision files.
To determine what type of skeleton hierarchy to import
• Select either of the Skeleton Description Mode options:
- Hierarchy of Nulls creates a skeleton hierarchy of nulls.
You must then constrain the bones of an existing skeleton or parts of an existing rig to these nulls.
or
- Bone Chains creates a standard skeleton hierarchy made of bones.
You can then set the Bones Skeleton Options to define the skeleton setup (see next page).
To define the skeleton setup
If you selected the Bone Chains option as the Skeleton Description Mode, you can decide how you want the skeleton to be set up in XSI.
• Select how you want the skeleton bone connections with the Hierarchy options:
- Connect with unanimated bones connects all bones, animated or not, as part of the skeleton hierarchy.
or
- Leave unconnected does not connect bones that are not animated.
• Select which structure you want for the resulting skeleton hierarchy with the Chains options:
- SOFTIMAGE|3D Mode creates SOFTIMAGE|3D-style chains whose effectors are children of the last bone in the chain (see Drawing Chains à la SOFTIMAGE|3D).
or
- SOFTIMAGE|XSI Mode creates default XSI-style chains whose effectors are children of the chain root (see Effectors).
You can select how you want the animation and group information to be set up as you import the skeleton hierarchy into XSI:
• Select Crop Motion Values to Limits to apply the DOF (degrees of freedom) limits in the ASF file to the animation in the accompanying AMC file.
The DOF limits are the minimum and maximum values allowed for the XYZ translation and rotation, as well as movement along the bone. Any values outside the minimum/maximum range are cropped.
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This option applies only to importing Acclaim files. |
• Select Override Bone Length Multiplier to override the bone length multiplier information in the ASF file to be applied to the animation in the accompanying AMC file.
If you select this option, you must then set the value with the Length Multiplier slider. This is the length (in units) of the bones.
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This option applies only to importing Acclaim files. |
• Select Add motion action to Mixer to add the accompanying keyframed motion as an action clip in the animation mixer.
• Select Group Animated Objects to create a group that includes all animated objects in the skeleton hierarchy.
Transferring the Mocap Data to Your Rig
Once you have imported the mocap files into XSI, you can constrain your rig to the mocap skeleton, then plot (bake) its mocap data to your rig. When you’re plotting, you can choose to save the animation in an action source so that you can use the animation mixer, or simply create a library of sources—see Plotting (Baking) and Storing Mocap Data for more information.
You can constrain the skeleton and rig together in different ways, depending on which elements of your rig are IK and which are FK.
• For IK elements, one common way is to pose-constrain the IK effectors, roots, and IK control objects (including up-vector controls) on your rig to the appropriate elements on the mocap skeleton’s.
• For FK elements, such as arms, you can orient-constrain your rig’s bones to the mocap skeleton’s bones. If the resulting orientation on your rig’s bones is not correct, modifying their rotation order may help—see Changing the Bones’ Order of Rotation.
For more information, see Constraints and Rigs.
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Make sure to have Constraint Compensation on when setting constraints to keep the current offset between the constrained elements. |
Instead of constraining your rig to the mocap skeleton, you can also retarget the mocap data from one rig to another, and then plot (bake) the animation onto your rig. See Overview of Retargeting Animation for information.
Plotting (Baking) and Storing Mocap Data
After you’ve applied mocap data to your rig, cleaned it up, added offsets to it, and so on, you may want to bake all this animation data into fcurves that you can edit. To do this, you plot the animation. When you plot, you can choose to keep or delete an action source after the animation is plotted. See Storing Mocap Animation in an Action Source below for more information.
Plotting evaluates the animation frame by frame and creates fcurves that are applied to the character’s rig controls. Plotting is done by first creating an action source, which you can keep or discard after the plotting has finished.
For more information in general about plotting, see Plotting (Baking) Animation in the Animation guide.
To plot the mocap animation
1. Branch-select the character rig whose animation you want to plot.
To plot the animation of the rig’s children objects as well, branch-select the character and then choose Select > Select Child Nodes.
2. Choose the Tools > Plot > All Transformations command from the Animate toolbar.
This plots the local transformation (scaling, rotation, and translation) parameters. All local transformation parameters are plotted, whether they are animated or not.
3. In the Plot dialog box, specify the frame range and step value, the type of fcurve you want to create, and whether or not you want to keep the resulting action source that is created from plotting.
Click the help icon (?) in this dialog box for more information on each of the options available.
4. Click OK to plot the animation.
Storing Mocap Animation in an Action Source
An action source is a “package” of animation. Once you have created an action source, you can apply it on the same model or share it with different models. You can create an entire library of actions and share them among any number of models. You can also load it into the animation mixer as an action clip where you can manipulate it in a number of ways.
For general information about actions, see Actions in the Nonlinear Animation guide.
To save an action source
1. Select the rig elements that are animated with the mocap data.
2. Choose Actions > Store > Animated Parameters - Fcurves from the Animate toolbar.
You can also choose another “Fcurves” command, depending on how you have your model set up—see Choosing What to Store in an Action in the Nonlinear Animation guide if you need more informations.
3. In the Store Action dialog box that appears, give a name to the action source and set the number frames over which you want the action clip to last (the Default In and Out values).
If you want to add the action source directly to the animation mixer, select the Add Source as a Clip in the Mixer option. You can also set the Clip Offset, which is the frame at which the clip starts in the mixer.
4. When you click OK, the animation is stored as an action source that you can find in the model’s Mixer > Sources > Animation folder in the explorer.
All original action sources in a scene are saved in the Animation (Sources) > model folder (select the Sources/Clips > Animation scope in the explorer to find them).
SOFTIMAGE|XSI v.6.01