There is a lot that goes into creating a believable walk cycle, you need to understand how the human body moves, and the key positions we go through during a walk. Walk cycles are a key component in video game animation, if a character is going to move they are going to need to have a walk cycle. The walk cycle is often one of the first animation tests done for a new character in a film because it's a great way to get comfortable with the rig as well as establish a personality. In this article, I'm going to walk you through the key steps of creating a walk cycle inside of Blender. If you're brand new to character animation inside of Blender I recommend first checkout out Learning the Basics of Blender Animation Tools article.
Before you begin animating a walk, you need to know the basic formula. That's right, when it comes to walk cycles there is actually a good formula that will help you create a believable walk cycle every time. Of course, this formula is really for a very basic walk, the type of walk you see when someone is walking down the street, or strolling through the mall. There are four main poses and an average of 12 frames per step, so 24 frames for a complete cycle.
You can see in the image above the main poses involved with a walk cycle, these poses are going to give you the foundation for a great walk. Of course, the poses can be tweaked and exaggerated where needed, but you can see the motion that the body goes through during a walk. In the animation world this type of walk cycle is often referred to as the "Vanilla Walk". Since we are going to be animating a vanilla walk cycle, our posing will not deviate very far from this basic structure.
After a quick Google search for "Walk Cycle" you'll be presented with a large list of images displaying the main poses and timing involved. However, it's still beneficial to either find video reference online, or even get up and shoot some of your own. Make a mental note of the motion your body goes through during the walk, and really study the reference to learn how the weight transitions from side to side and the rotation of the hips and upper body. The more planning that you do beforehand will only benefit the quality of your walk cycle.
Creating the Contact Positions of the Walk Cycle
The rig we are going to use is the classic DT Puppet, which is an excellent body mechanics rig. You can download the Blender file here: DT_Puppet_Rig. With any walk that you create, the first thing you'll need to establish is the contact position. For a 24-frame walk cycle there is going to be a total of three contact positions.
With the Blender scene open, change the frame range to end at frame 25, so that it will be a looping animation. Also, set the keying channel to LocRotScale, so that every channel will have a keyframe applied to it. With that set select the little red icon next to the keying box to enable auto keying, this way, any changes you make will automatically get a keyframe applied to it.
Now go to frame one on the timeline and begin posing out the character, study the reference video you recorded or found online, or revert to the above image to get an idea of the basic structure for the contact position. A basic rule of thumb is that you want the leg with the heel planted on the ground to be almost completely extended. Now, you can keep a little bend in the knee so there isn't a lot of popping during the cycle. (Remember that you have to be in Pose Mode to manipulate the rig)
When you're happy with the pose press "A" to select all the controls and select the set keyframe icon to lock a keyframe down for all the controls. The reason you want to set a keyframe for all the controls is because once you start getting into more poses, you don't want things to start moving at different times.
The next step is to create the opposite contact position, which is going to be the exact same pose but just flipped, so now the back leg is going to be forward. The easiest way to create this pose is to press "A" to select all the controls, and go to Pose>Copy Pose>move to frame 13 now, and go to Pose>Paste Pose. This will create a duplicate of your first contact position on frame 13, which is the frame at which one step is completed. The process now is a little time consuming, but will ensure you have a clean cycle. Take the foot that is planting on the first contact position; copy all the location and rotation values onto the planted foot for the pose on frame 13. So you're basically going through the process of mirroring the contact positions. The arm that is extended back on frame 1 is going to be the arm that is extended forward on frame 13, and so on.
When you've successfully created both contacts positions, take the pose on frame 1, go to Pose>Copy Pose>move to frame 25 on the timeline and go to Pose>Paste Pose> This should give you three contacts, resulting in three complete steps.
Creating the Down Positions of the Walk Cycle
Look at the images above you can see the next major key pose for a walk cycle is the down position, this is when the body is at its lowest, and the weight has begun to shift over the supporting leg. The back foot is starting to raise up and really peel off the ground. However, at the down position, you don't want the back foot to be off the ground yet, keep the front toes still planted, and the heel of the foot raised up. You want to create this pose on frame 4, and on frame 16.
You also want to make sure the upper body starts to drop down as well. You want to keep this pretty subtle. If you look at someone walking regularly you'll notice the hips drop, but it's not a significant amount. Once you begin exaggerating this, you can start to add a bit more personality to this walk. In this case, though, I kept it very close to what you see in the real world, because it is a 'Vanilla Walk' after all so we're just focusing on nailing the body mechanics and getting it to look believable, rather than worrying about adding character and personality. That can be saved for a different tutorial all together.
Something you want to do for the down position is actually raise both the head and upper chest slightly. Since the lower body is dropping down as the weight gets planted on the contact foot the upper body is going to drag slightly behind. Therefore, at the down position the head and chest will be rotated back slightly to help show this.
Once you have the first down position created go to frame 16 and create the down position for the next step. Do what you did before, copy the attributes from the first down position on frame 4, and paste them onto frame 16, creating a mirror of the pose.
Creating the Passing Position of the Walk Cycle
The next pose is the passing position, this is when the body begins to lift up again, and the back leg is now completely off the ground and the knee is bent. Both arms should be at the characters side. This is the mid-way position in the walk.
For the passing position you want to begin rotating his head and chest forward because they are now caught up with the rest of the body.
You don't need to bring the foot high off the ground, since this is a basic walk it can be pretty subtle, and we as humans like to use as little energy as possible, so when we do walk we raise our foot just high enough on the ground so it doesn't touch.
You're going to create the passing position on frame 7 and frame 19.
Creating the Up Position of the Walk Cycle
The last key pose you need to create is the up position; this is actually when the body is at its highest position. Your instinct when creating your first walk cycle may be to have the contact be the position when the hips are the highest, but that isn't actually the case. The up position is typically slightly higher than the contact, because the body is starting its descent on the contact position.
The Up position should be created on frame 10 and frame 22. Now that you have all the main poses established, you should now have a walk cycle that is moving in a believable way! Just by created these four main key poses it gives you the foundation of a solid walk. All that's left to do now is fine-tune the animation and start to add that final polish.
Polishing the Walk Cycle
The last step is to add that final 10% to the animation, add in things like lead and follow on the head, drag on the wrist and arms. As well as make any final adjustments to the animation overall. During this pass, I did another run over the hips and feet to try to eliminate some of the popping in the knees that often occurs during a walk.
You can also add some animation to the fingers as well, to make sure they are moving properly along with the walk, so that they are not stuck in the same pose throughout the animation.
You can see the final animation above. A walk cycle can seem like a daunting animation to tackle, but if you've done the proper planning, studied the four main poses involved, and timed it out correctly a walk cycle is actually one of the simpler animations to achieve. Now, this was just a very basic "vanilla walk' you can experiment with the timing as well as the poses to try and add more of a personality to the walk.