By naming a pose _onMouseOver you indicate to the arcticPigs viewer that you want to linking this pose to a mouseOver/ mouseOut event. You can link the pose to the whole model, or if you specify a group name, you can link these effects to only part of your model.

If the mouse event occurs, the pose gets 'executed' by moving the pose slider to +100. The time the viewer takes to do this slide can be specified. As soon as the event is no longer valid (the mouse moves to a different group or the left mouse button is released) the pose slider will be put back to +1. The time taken for this move can be given independently of the fade-in time.
We chose +1 as the 'inactive' slider value as Animation Master will not allow you to enter keyframe data at the t=0 point of your pose. By using +1 you have maximum flexibility in defining your rollover effects.
Finally you can also specify if the pose action should be executed as an 'add' or as a 'replace' type action. The default is 'add' which will simply add the action to whatever else is going on in your scene. The replace option will override any actions that may be playing on your model.

_onMouseOver( [Frames fadeIn] [Frames fadeOut] [flags] ) [groupname] 

fadeIn

Optional value. The number you enter here is taken to mean the number of frames (at 30 FPS) you want the viewer to take over the fade in. The fade in is a linear move from +1 to +100 on the pose slider value.

fadeOut

Optional value. The number you enter here is taken to mean the number of frames (at 30 FPS) you want the viewer to take over the fade out. The fade in is a linear move from +100 to +1 on the pose slider value

flags

The flags can have the following (optional) value(s)
R This puts the blend into replace mode. By default the pose action is blended as an add type blend. This will simply add the action to whatever else is going on in your scene. The replace option will override any actions that may be playing on your model with those you defined in the pose.
T Toggle mode. In this mode the blend is always executed till the final value over the time you specified for the fadeIn value. The pose then stays at this value, even if the mouse has moved out of this group or model in the meantime. A second 'touch' will start the fade out.

groupname

Optional value. If specified, the pose will only execute if the mouse is over the specified group. Else the rollover effect starts if the mouse is anywhere over the model.