Using the BodyKinematics Tool in Python
Posted: Wed Sep 27, 2017 7:38 am
I'm trying to run a BodyKinematics analysis of an IK (.mot) file so that I can quickly obtain center of mass information for the duration of the motion, but I'm having a problem. Namely, it seems as though there is no method to actually run the tool. Now, there *is* a tool.begin() method. But that only seems to process the first frame. And one might think, "what about the tool.step() method?". Well, that doesn't seem to actually do anything. It doesn't seem to matter whether or not you step it or try tool.proceed(), it will iterate for forever and when you include an end iterant and you try print the results, you will still only see the first frame. My code thus far is as follows (ikPath ikFile, outFile, results, are all system-specific paths or file names):
I've tried a few different approaches, such as iterating over steps, and using bk.step alone or with proceed, but nothing works. I get no real results - just the first frame, and that's it. For example:
I hope I'm just missing something dumb and obvious here, that working on getting the tool working has blinded me to something in front of my face. It's been a while since I've used Python too so maybe that is contributing here, but either way, I'm at a loss as to why the methods that seem like they'd run the analysis don't seem to do anything at all.
As always, any help is appreciated. Thanks!
Code: Select all
timeFile = 'irrelevant path and file'
times = []
with open(ikPath + ikFile) as to_read:
with open(timeFile, 'wb') as tmp_file:
reader = csv.reader(to_read, delimiter = '\t')
writer = csv.writer(tmp_file)
desired_column = [0]
for row in reader:
myColumn = list(row[i] for i in desired_column)
times.append(myColumn)
times = times[9:len(times)] # exclude all the headers
times = [[float(float(j)) for j in i] for i in times]
startTime = min(times)
stopTime = max(times)
curModel = osim.Model(modelPath + modelFile)
curState = curModel.initSystem()
prefix = ikFile.replace('IKResults_File_Name.mot', '_BK')
bk = osim.BodyKinematics(curModel)
bk.setModel(curModel)
bk.setRecordCenterOfMass(True)
bk.setStartTime(startTime[0])
bk.setEndTime(stopTime[0])
curState = curModel.initSystem();
bk.begin(curState) # this apparently only processes the first step
bk.printResults(prefix, results)Code: Select all
b = 0
i = 1
while b is 0:
print i
b = bk.step(curState, i)
bk.proceed(bk.step(curState, i))
i = i + 1I hope I'm just missing something dumb and obvious here, that working on getting the tool working has blinded me to something in front of my face. It's been a while since I've used Python too so maybe that is contributing here, but either way, I'm at a loss as to why the methods that seem like they'd run the analysis don't seem to do anything at all.
As always, any help is appreciated. Thanks!