Exporting the animation of an object to a text file with custom code

Question

I've seen a lot of discussion on how to animate an object from a text file, and I'm attempting to do the opposite of that.

To clarify, I want a program that goes frame by frame and writes the location of an object to the file, line by line. (line one has the X,Y,Z of the object on frame 1, line two has the X,Y,Z of the object on frame 2, etc...)

The problem that I am having is that when I run the code it writes down the location of the object 5 times, all from the same frame. (It writes down a bunch of [5.0 0.0 0.0]'s). So I believe that this is a problem with the line that changes the frame not being updated correctly when I run the code.

I should state that I'm coming from basic java knowledge and have almost no idea how python works. I'm using a for loop and I want the frame to be bumped up one every time it goes through a cycle. I know how to do this in java, but not in python.

Hope I explained this correctly, thanks for the help!

My code:

obj = "Cube"
filename = "file" 
filepath = 'FILEPATH'
combinedpath = os.path.join(filepath + filename + ".txt")
SAVEFILE = open(combinedpath,'a')

for i in range (0, 5):

    #frame set line (is this the problem?)
    bpy.data.scenes["Scene"].frame_current = i

    #location grabbers
    locnab0 = bpy.data.objects[obj].location[0]
    locnab1 = bpy.data.objects[obj].location[1]
    locnab2 = bpy.data.objects[obj].location[2]

    #location converters
    ink0 = str(locnab0)
    ink1 = str(locnab1)
    ink2 = str(locnab2)

    #write to file    
    SAVEFILE.write("\n" + ink0 + " " + ink1 + " " + ink2)

SAVEFILE.close()

Answer 1

I am trying to do something similar, and the trick for me was to use this to advance the playhead...

bpy.context.scene.frame_set(i)

The below gave me the current frame over and over. Even though it did advance the animation in the viewport...

bpy.data.scenes["Scene"].frame_current = i