Week 3: Walk Cycle

Walks are the hardest things to animate well: walks can tell a whole story. Walks are full of personality character, animation problems, full of weight distribution, energy and flow (or lack of it). The key is breakdown a structure (the walk cycle) of a walk and work in order, figuring out the rhythm, where is the weight coming from and where is transferring to. There are all kinds of walks: everyone walks differently. So, is a diverse and complicated topic: everything from gender, physical size to emotions can alter a walk has to be put into a context.

The walk cycle elements are:

  • Sticky foot contact, the feet slides backwards slightly but towards the end it moves forward.
  • Raising and fall of the head level, which is a subtle element but crucial.
  • While Animate there should be used 25 frames, for example, where the first and last frame are identical. However while we play the animation the 25th frame should not be played but should be used 24 frames.
  • Weight shift: the body sway from side to side. There should be a counter pose of the shoulders and hips going in opposite directions, and also shoulders an legs.

This is a sketch representing the rough timing for different single steps within a walk or run.

In this week post I am going to use 12 frames a second to create a natural walk with two steps a second.

There are some elements that can upscale a walk cycle:

  • Personification of emotions: is a useful exercise to try and convey specific emotions through a walk cycle. (e.g. happiness, sadness, however there are many words to express them so it is important to have a clear idea).
  • Observation of reality through reference video and pictures: recording footage of a walk of a diverse set of people at different times.
  • Story or role based (characterisation): the personality, the physique or skills of a character will define the walk. However, it depends also where is the story set.

Workshop

With a basic rig of a ball with legs I am going to create a simple walk cycle.

The rig controls:

The position control, used to make the character move forward once the basic mechanics of the walk are set.

Centre gravity control, to edit the pelvis movement and add the squash and stretch to the body. there is also the option to add a moustache to be animated to add character.

Feet control that also have the controls to move heel and toe.

Pole vectors that control the legs orientation.

The first sep of the Animation was to block the rough mechanics of the walk cycle. Saving the first pose and last (frames 1 and 25) with a step pose (one foot in front of each other) and an reverse pose (switching feet and balance of the pelvis, centre of gravity) around frame 13 via copying the copy over to make it symmetrical. At frame 7 the character is going to move slightly upwards and to establish the leg which is moving forward, which would be in the hair, and the leg which is going backward, which should be on the ground. Same process but reversed for frame 19. For this stage the side view was very useful to key the poses and in terms of copying them throughout the timeline the middle click and drag tool was very practical. When I preview the animation I only played 24 frames.

Next I added some pose in between (frame 4 and 10 and 16 and 22) to add some rhythm to the whole animation and see what I could add in terms of personality before the poses are cleaned up in the graph editor. At frame 4 and 16 (reversed) key the contact pose of the feet the foot dropping quicker and low the root control so that it catches his weight. At frame 10 and 22 (reversed) the character goes upwards and add a ball roll to made the leg bend to the contact leg. To give some some personality to the character, I accentuated the toe flop of the feet as it comes down or when the foot is coming up. At this point there is the mechanics of the walk.

This was the first output, however the rotation of the pelvis needed to be fixed since and it is clear from the video.

Next step was to clean up the movement in the graph editor to achieve nice curves with no bumps in the animated keys and also create some slow in and out by adjusting the tangents for each translate or rotate in the axis.

In order to stop the knees to “pop” in the walk I edited the value for the leg Stretchiness in the feet controls, only in some poses (10, 22, 7 and 19 -slightly-). I created a down pose and up pose for the character squash and stretch to create a bounce for the walk. To add a bit of personality to the walk I have switched on the moustache controls and used them as secondary action and overlapping action to the walking by making them move up and down as the character bounces up and down. I also offset they movement for the overlap effect. In order to make it move forward I used some markers, locators, t mach the heel (first part of the cycle) and toe (second part of the cycle) of the feet to use as a guide to move the character forward in space using the translate z.

I have also edited the appearance of the character to add a bit a personality to it.

I finally added more steps by grabbing each control, copying them and paste and connect (adding the positions rather that just repeating them) them in the space of 100 frames.

This is the final output from both side and front views:

As an additional exercise I worked on an angry walk using another rig (from “Avatar the last airbander” Aang).

I first studied the rig and see which where the most suitable controls fro this walk. I after applied the notions gained from this week workshops and using them as a starting point.

This is the first part where I blocked the basic mechanics of the walk.

The next step was to create the breakdowns in between the main frames to clear the movement and create a natural walk steps with all the controls of the rig: adjusting the feet controls the spine controls position and edit the expressions controls to make the character look angry, fed up, even adding a rotation and swing back and forth the arms (closer to the body and far from it alternating) in an accentuated way to highlight his angry mood and also rotating the hands as he proceeds into the walk. However, the first attempt resulted in a quite “stiff” animation since the spine was not curving enough and the centre pelvis of the character had do be animated to go up and down and rotate as well. So I work on this aspect and this is the result:

I after put the animation frame to 100 and and copy and paste connect the keyframes of the walk. I have also positioned the eyes aim control further down so that when the character walks the eyes would not move too much.

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