The feeling of weight is something extremely important to your animations, making them look believable. When looking at shapes on a screen (be they realistic, cartoon, or abstract), the way they move frame to frame is what makes the audience perceive their mass.
The weight lifting exercise is one of the most repeated in animation schools worldwide. This is where animation students can test and learn the body mechanics necessary to express the feeling of weight with animated shapes. In this recipe, our character is dressed as a thief and will try to take a safe full of money with him.
It's a good idea to act it out yourself (maybe recording it, if you have a webcam or better equipment) to figure out the body mechanics involved. As with in any animation shot, you should plan what you want to accomplish with rough sketches or using Blender's Grease Pencil function.
- Open the file
008-Weight.blend. It has our character properly dressed as a thief and a safe in front of him. By the size and nature of the safe you see in the next screenshot, we can tell this is not going to be easy for him:
Note
Here we're going to focus only on the strict act of lifting the safe. In a complete scene, it could be interesting to add a little preparation before the attempt at lifting. When planning for the shot, maybe you can make the character look at a good place to hold it, try using devices or tools to break in, and so on. For learning and brevity's sake, only the mechanics involved in the actual lifting will be covered. The acting required to make this shot more interesting is beyond our scope here.
- Since our character's hands will be fixed holding the safe, this is a perfect case for using IK in both arms. Trying to match the position of the arms, hands, and the safe in FK would be too difficult, and it would affect the overall quality of your animation. So, make sure you're at frame 1, move (G) both IK-FK sliders for left and right arms to put them in the IK position, and insert a location keyframe (I) for them, as seen in the next screenshot:
- Another thing that you should consider changing is the "space" evaluation for both IK hands from "Ribcage" to "World". In the "Ribcage" mode, the hands controllers will follow every transformation made to the torso. Here we need to make the hands stick to the safe while being able to move the character's torso freely to enhance the feeling of weight involved. Move the two hand "space" controllers (Space_Arm.R and Space_Arm.L) to the World position and also insert a location keyframe for them.
Now you have the rig set up to start the blocking phase. It's important to have this configuration defined prior to the blocking stage because it can be harder to fix the poses if you change the settings after creating them.
- In the planning phase we define the basic Extreme poses needed for this action. Here, the first Extreme is when the character holds the safe to start the lifting. You should use the Quad View (Ctrl + Alt + Q) to have a better notion of what your pose looks like from all angles, as seen in the following screenshot:
- Now that you have the first contact between the character and the safe set in the Extreme pose, you need to create a Child Of constraint for the safe object. This is the same situation described in Chapter 6, Blending With the Animation Workflow, in the recipe Grasping and throwing objects.
- Since both hands are holding the safe, it would be good to move them together so they remain fixed on the safe's surface while moving it around. This is just a matter of adding another Child Of constraint to one of the hands just like we did with the safe object. In our case, make
Hand.Rthe child ofHand.L. When moving theHand.Lbone, both the safe and theHand.Rbone will follow nicely. You can move the right hand and add keyframes to it at anytime, if you wish.A different challenge is when you need to rotate the safe in a pivot point different from the bone that is a "parent" of the safe and the other hand. The pivot point of the hand is in its wrist, but we need it to rotate around the safe's edge.
- To achieve this, place the 3D cursor at the position where you want this pivoted rotation to happen either with a left-click on the 3D View on the desired location; or selecting an object located exactly at the place where the pivoting should happen, press Shift + S and choose Cursor to Selected. Then you should select both hands controllers, press. (the period key), and rotate them nicely. The. shortcut tells Blender to rotate the selected objects around the cursor instead of the objects' centers. You can also choose how the pivot point should be evaluated on the selector placed at the 3D View header, as seen in the following screenshot:
The following screenshot shows our pivot in action. Here the 3D cursor is placed near the edge of the safe, as if the safe edge is in contact with the ground. If we didn't use a pivot in this case, the safe would rotate around the root of the Hand.L bone, which is located above the ground. The arrows indicate both the pivot point and the rotation that happens with this method:
- Now start making the next Extreme poses without thinking about the Timing between them. Just make sure your poses look good and can be clearly "read" in Camera View (Numpad 0) for now. The Extreme poses here are crucial to give the feeling of weight: since the safe is very heavy, it shouldn't move much despite our character's huge efforts. The timing, which we'll adjust later, will work along with the spacing to make the safe look very heavy.
Note
Chapter 7, Easy to Say, Hard to Do: Mastering the Basics has more information on Timing and Spacing, if you need a clearer understanding on those concepts.
In order to move the safe out of the frame, our character needs to make an enormous effort. In this case, that means we need a good amount of Extreme positions to reflect all of his pulling and pushing to take the safe with him. In the complete example, there are 18 Extreme positions to reflect all of his effort to move the safe. For brevity's sake, the next screenshot shows just some of them:
- After you're happy with your Extreme poses, let's make the timing adjustment. In the DopeSheet window, select all saved Extremes, press R, and select Extremes to shade them in a pink hue and make it easier to distinguish them from Breakdowns and regular keyframes later. Make sure the Summary option is enabled in the window header and start dragging the Extremes on the timeline until you're happy with the timing.
- With the Extremes carefully created and with its Timing adjusted, you now may create the Breakdowns and additional keyframes to make the animation more fluid, with overlapping actions and follow through. Don't forget to use the tools in Blender to track the arcs made by the bones as demonstrated in Chapter 6,
- Once the main body movement looks good, move on to add details such as fingers, eyes, and facial expressions. It's a must to work from the lesser to the higher levels of detail to ensure a workflow where it's easier to make adjustments and fixes. Having the saved positions colored in different hues to distinguish Extremes, Breakdowns, and regular keyframes is also very important. The facial controllers are located on the first bone layer of the armature, as indicated in the next screenshot:
- When you finish setting all those positions, it's time to work on the F-Curves, adjusting the eases and creating favors as explained in Chapter 7,
The file 008-Weight-complete.blend has this finished example which you can explore for reference, although it's strongly suggested that you to come up with your own touch for this scene.
By combining the concepts and principles of motion such as easing, timing, spacing, anticipation, and use of the Child Of constraints, you can create a scene where your character lifts a heavy object. A proper planning phase and reference analysis allow you to know what features of the rig should be used, while understanding how Blender works with different pivot points helps you to be more efficient and create convincing actions.
Appendix: Extremes, Breakdowns, Inbetweens, ones and twos
Chapter 6: Grasping and throwing objects
Chapter 6: Animating in layers
Chapter 7: Easy to Say, Hard to Do: Mastering the Basics