[x3d-public] HAnim Displacer Operation

[Joe D Williams]

HAnim Displacer Operation

'''HAnim skin with Displacer'''

Example is here:

[http://www.hypermultimedia.com/x3d/hanim/JoeLevel2LOA3SSPYRWRJKDNoGeometry.x3dv]

The example combines the single mesh skin animated by joint(s) 
binding, with a Displacer providing additional animation for specific 
vertices.

In this case, the 10 standard feature points of the head are 
'expanded' by the Displacer.

In practice, Displacer animations for the skin mesh are contained by 
the first Joint that references the skinCoordIndex of the skin. 
Following shows the insertion of the Dispacer node into the skullBase.

 ...
 DEF hanim_skullbase HAnimJoint { name "skullbase"    center 0.0 
1.63 -0.01
 skinCoordIndex [ 0 1 2 3 4 5 6 7 8 9 ]
 skinCoordWeight [ 1 1 1 1 1 1 1 1 1 1 ]
  displacers [
     DEF Joe_skull_tipTest Displacer {
      weight 0
      name "skull_tip_raiser_action"
      coordIndex [ 0 1 2 3 4 5 6 7 8 9 ]
      displacements [
 0 0.15 0,
 0 0 0.15,
 -0.1 0 0.15,
 0.1 0 0.05,
 0 -0.02 0.05,
 -0.15 0 0,
 -0.05 0 0,
 0.15 0 0,
 0.05 0 0,
 0 0 -0.15
   ]
  }
 ]
 children [ ...

The Displacer is initialized by the weight, coordIndex, and 
displacements fields as follows:

 HAnimDisplacer
  coordIndex    [
   numerical index of each parent geometry vertex to be animated
   index is order of appearance of vertex in user code for parent mesh
              ]
 displacements [
   maximum relative x,y,z displacement in skeleton space of each 
vertex at maximum weight
   same order as coordIndex
              ]
 weight        0 to 1 animation control
  (from  ScalarInterpolator)
  (linear interpolation)
  0 = same location as parent mesh initial vertex
  1 = defined maximum relative displacment of parent mesh vertex

So, the main idea is to establish displacements that represent the 
final position of the specified vertex relative to the initial 
position of the vertex. If the weight value is defined as 0 then there 
is no added displacement. If the weight is 1 then the vertex is 
dispacemed relative to the specified vertex. If the vertex has been 
animated by Joint(s) rotation, then this dispacement is added to the 
vertex in the animated poition.

Please notice the definintions used in this skin field:

  skin [ ...
 0.0 1.77 0.0               #0 skull_tip
 0.0 1.665 0.09             #1 sellion
 -0.033 1.62 0.087          #2 r_infraorbitale
 0.033 1.62 0.087           #3 l_infraorbitale
 0.0 1.55 0.097             #4 supramenton
 -0.077 1.64 -0.01          #5 r_tragion
 -0.0527 1.58 0.015         #6 r_gonion
 0.077 1.64 -0.01           #7 l_tragion
 0.0527 1.58 0.015          #8 l_gonion
 0.0 1.625 -0.0925          #9 nuchale
   ]...

Both the initial skin vertex locations and the displacments are givin 
in skeleton space.

For this example, when the Displacer weight is 0, then the skull_tip 
vertex is animated only as a result of various Joint rotations applied 
to the skeleton and thus to the skin vertices. If the weight is not 0, 
then the Displacer displcement value is added to the skull_tip 
location.

In this example the Dispacer is controled by the following timer and 
ScalerInterpolator to provide weight values to the Displacer node.

 DEF DisplacersAnimation Group {
  children [
 DEF skull_tipTestTimer TimeSensor {
  cycleInterval 5.73 loop TRUE enabled TRUE }
 DEF skull_tipTest_Run ScalarInterpolator {
  key      [ 0 0.1 0.2 0.35 0.65 0.7 0.85 0.95 0.98 1   ]
  keyValue [ 0 0.2 0.4 0.6  1    1   0.85 0.55 0.25 0 ] }
 ROUTE skull_tipTestTimer.fraction_changed TO 
skull_tipTest_Run.set_fraction
 ROUTE skull_tipTest_Run.value_changed TO Joe_skull_tipTest.weight
  ]
 }

Sorry I didn't make a button to turn on/off the Displcaer timer yet. 
When you run the example and select Default, only the Displacer 
animation is running.

Joe

http://www.web3d.org/wiki/index.php/About_the_X3D/VRML_ROUTE_statement