Adding frames without keying sets

Coding Beginning Blender Code and Development
1

I would like to create an animation of random poses as I have mentioned in another post. I do not want to use any form of interpolation.

How do I write a script to do build this sequence for me in python?

So as an example I have the cube and a defined animation length in my timeline as 20 frames.


import bpy
import random

cube = bpy.data.objects["Cube"]

i = 1
while i < 21:
    bpy.ops.anim.change_frame(frame=i)
    bpy.ops.anim.add
    cube.rotation_euler = (0, random.random(), random.random())
    # What goes here?
i = i + 1

How do I set the cube rotations for each frame?
I thought it should be something like bpy.ops.anim.keyframe_add but I dont think it is because then it requires a keying_set which is only relevant for interpolated data.

2

Similarly you can also use the driver system


import bpy
from  random import random

def random_rot():
    return random()

bpy.app.driver_namespace["rand_rot"] = random_rot

Now you can go straight to the rotation properties boxes and type in


#rand_rot()

wherever you want random rotation. You could restrict it to a frame range too


import bpy
from  random import random

def random_rot(frame,frame_range=(-9999999999,99999999),default_val=0.0):
    if frame in frame_range:
         return random()
    else:
         return default_val

bpy.app.driver_namespace["rand_rot"] = random_rot

then if you want random rotation for 20 frames


ran_rot(frame,frame_range = (1,20))

You will always need to pass frame in this case. frame is already defined to the driver system as the current_frame.

3

Cool stuff i never had any idea about :spin: thanks :smiley:

4

Thanks @Brenel and @batFINGER, both your posts were extremely useful!

For anyone who uses this method and you want to remove the handler one way is to just type

bpy.app.handlers.frame_change_pre.pop()

in the Python console which will remove the last handler you added.