Wayne Mitchell (nole93)

3 answers · asked @ video mark 4:31 · Lesson: Rivet Walk Cycle - Translation · Course: Blender Animation Bootcamp

Copy Action To The Other Side


I must be a moron because no one us has ask this so far and I am completely lost on what are you are doing at time 4:31.  This is where you are copy the data from one foot to the other foot.  I am lost when you copy the first keyframe and move it to the second to last keyframe and do something.  After that I know what  you are  saying to do but it doesn't make any sense to me. For example, how can you put the first keyframe and locate at the second to last keyframe.  I am lost Can anyone explain it another way for my small brain.  



  • crew

    Hi Wayne, you don't have a small brain.  It is a little known fact but anyone called Wayne has a very large brain!

    True fact.

    What I'm doing in the video is mirroring the animation on both feet in the same time.  Then I need to duplicate it so it is twice as long, shift is backwards half a cycle and then cut off the excess keyframes (this is because the other side starts and ends halfway through the cycle).

    The final step is to fix the translation.  That is what I am doing at that point in the video that you have pointed out.

    I am shifting the location of every keyframe backwards exactly half a step distance. However, with the very last keyframe I copied it from the one that I already fixed which is 1 full step behind where it needs to be on that specific frame.

    I hope that makes sense.   Try not to get bogged down into the exact things that I'm doing on each frame and think about it as the entire process.

    To recap:

    1. Delete one side (except for the first key because Blender needs the channels to paste the data to)

    2. Copy the exact mirror over to the other foot.

    3. Duplicate the cycle then offset it half a cycle (12 frames)

    4. Delete the excess frames.

    5.  Shift the translation back half a step on each frame

    6. Have a cup of tea and high five yourself because you did something awesome

  • Thanks Wayne, I think I have it.  I will go and it a try.  I am still a little confused between steps 3 and 5, they sound like the same thing to me.    I will let you know if I need anymore help.  I truly  appreciate you taking the time to respond to my question in such detail.



    P.S. I not sure about that big brain theory yours :(

  • crew

    With steps 3 and 5...

    Step 3:

    This is because one foot has the contact frame half way through the cycle on the other side (in the timing)

    So if you want it to loop correctly.  Repeat it, then slide those keyframes back half a cycle (in the timing).  That way, you have shifted the timing so each step  happens in order.  That is, left foot, right foot, left foot, right foot etc.

    Otherwise when you mirror it, it will be the left foot AND the right foot stepping at the same time, which is not what we want in the walk cycle haha.

    Step 5:

    This actually fixes the location of each step.  Because when you walk, one foot lands in front of the other.  If you  didn't fix this, then each step will land in the exact mirrored location as the other foot.  But you want each foot to land exactly half the distance of the whole cycle in front of the other foot.

    That probably makes it sound more complicated than it is.

    Try watching it again, once you understand this trick it will start to make sense.

    It really is just an animation hack to speed things up.  

    Another way to do it is to copy from one side of the cycle 1 keyframe at a time and then paste the mirrored version to the corresponding pose (at the different timing) and then fix the location.  But this way is harder for a translating walk cycle (much easier in an in-place walk cycle because you don't need to fix the location)

    Hope that helps.