The Motion Builder scripting interface allows users to edit and query FCurves directly. It's fantastic.
To start, you may need to update your python path to include the directory to the file pyfbsdk_additions.py
sys.path.append('C:\\Users\\alinen\\AppData\\Local\\Autodesk\\MB2011\\config\\Python')
The following scrpit normalizes the character's ground contacts so that they are always at floor height. A simple approach is to find the minimum of the Y curve of each foot effector and then offset the curve so that the lowest point is at the target height. The script ToesToFloor.py will normalize the foot heights at contact for every take in the scene. Be careful when running these scripts: make sure that you've plotted the animation curves to a control rig and that the BaseAnimation layer is selected first.
def ToesToFloor(nodeName):
model = FBFindModelByName( nodeName )
ycurve = findAnimationNode( 'Lcl Translation/Y', model.AnimationNode ).FCurve
lowest = 99999999.0
for lKey in ycurve.Keys:
lowest = min(lowest, lKey.Value)
offset = 0-lowest # translating to zero, could use user-specified value
for lKey in ycurve.Keys:
lKey.Value = lKey.Value + offset
ToesToFloor('LeftFootEffector')
ToesToFloor('RightFootEffector')
And similarly, the script ExportContacts.py will export annotations which indicate when foot contacts occur. The approach simply samples the curves for each foot and keeps track of the frames where they are zero.
contacts = []
samplingRate = 1.0/fps
startframe = (int) (fps*(startms/1000.0)+0.5)
for frame in range(startframe, startframe+numframes+1):
t = (int) (frame*samplingRate*1000.0)
time = FBTime(0,0,0,0)
time.SetMilliSeconds(t)
vleft = yleft.Evaluate(time)
vright = yright.Evaluate(time)
contacts.append((frame, vleft <= 0, vright <= 0))
frame = frame + 1
# Now save the result
dir = "c:/temp/"
filename = dir + lSystem.CurrentTake.Name + ".ann"
file = open(filename, "w")
lastcontact = contacts[0]
for contact in contacts:
if lastcontact[1] != contact[1] or lastcontact[2] != contact[2]:
str = ""
if lastcontact[1]: str = str + "ltoesSite"
if lastcontact[2]: str = str + " rtoesSite"
file.writelines("%d %d\n%s\n\n"%(lastcontact[0], contact[0], str))
lastcontact = contact
str = ""
if lastcontact[1]: str = str + "ltoesSite"
if lastcontact[2]: str = str + " rtoesSite"
file.writelines("%d %d\n%s\n\n"%(lastcontact[0], contact[0], str))
lastcontact = contact
References: