In the previous chapter, we learned how to create a rig from scratch using bones. In this chapter, we look at creating/customizing bipeds and learn how to use them to drive character animation. A preset character model is provided, along in the contents folder and the reference filenames. Feel free to use any custom 3D model you have or download one and follow along. You can use the Autodesk character generator to generate a character or use any other software that generates human characters. We will be looking in-depth at the tools and options available for bipeds in 3ds Max, such as biped types, Figure modes, Footstep mode loading and saving motions, animation of a biped, and the Motion Flow Editor.
Getting Started with Bipeds
Bipeds is an animation utility that is provided with 3ds Max to create bone structures for characters and creatures that have two legs. It’s mostly used to animate human figures, but animation of quadrupeds is possible too.
Creating Your First Biped
Command panel, biped creation
Biped’s creation parameters
Drag Height: Allows you to click on any viewport and create a biped with a custom height.
Drag Position: The biped is created at the point where the user clicks based on the height input of the biped rollout (as marked in the image).
U/I: The software will create a biped with the default options that are shipped.
Most Recent Fig File: This can be used if you have created, let’s say a biped with six fingers and a tall neck and a lot other parameters tweaked. That biped can be saved as a .fig file and then can be loaded later. This saves you a lot of time in customizing a biped every now and then.
Root name allows you to specify a name system for your bipeds. Otherwise, they are named as bip01, bip02, and so on.
Scene Explorer’s biped hierarchy
Biped: Body Types
Body types of the Bipeds
Note that the type of biped is just an aesthetic and for visual differentiation only. It does not affect the animation or ease of use.
Arms: When this checkbox is enabled, the biped will have arms. If not, the arms will be removed. Disabling arms will also disable fingers and knuckles.
Neck links: This determines the length and segment of bones for the neck area. Increasing neck links will make the neck tall like a giraffe neck.
Spine links: This allows us to create spine chain segment. The default is 4 and can be increased or decreased as per our requirements.
Tail links: Allows us to add tails to the biped. Why would we need a tail on a human character? With the right tweaks in the biped, this can be converted into a dinosaur rig.
Ponytail links 1 and 2: Allow us to add ponytails to characters, which is very useful if your character has long hair and you would like to animate the sway of the hair.
Fingers: Allow us to tweak the number of fingers in the hands. Note that this is symmetrical, so we do not have feature to make one hand have more or less finger. However, there is a workaround for that that we will discuss as we go forward.
Finger links: Allows for finger sections/finger bends.
Toes and Toe links: Work the same way as fingers, but for legs.
Props: These are useful when you are loading mocap data that has additional prop information; the prop that is added with the biped will receive the data and move accordingly. For example, a weapon in a character’s hand. The process of capturing an object/prop’s movement and rotation into 3D coordinates is called motion capture . A mocap file is nothing but a motion capture file that is captured using special cameras. The capture data contains the rotations and translation of the object and this data can be fed into 3D software to mimic the movement.
Ankle attach: Allows us to move the feet below the ankle a bit forward or backward without affecting the leg.
These options should help us create a customized biped. There are advanced options that we will look at as we utilize the biped for animation.
Biped, Figure mode editing
Biped: Figure Mode
Figure mode
Figure mode is a toggle switch. You can switch in and out of Figure mode. Figure mode allows you to move, rotate, and scale the biped parts so that the rig is even more customized to your liking. Let’s say we want to use this biped for a chimpanzee, so we need to elongate the hands. No problem. Enable Figure mode and scale them along the axis.
Load Biped_Figuremode_edited and see the reference.
- 1.
Create a biped.
- 2.
Get into the motion tab.
- 3.
Enable Figure mode in the biped rollout.
- 4.Use the necessary transformation tools (in this case, use Biped_Figremode_edited.max).
I scaled the elbow section of the hand along the x axis alone using the Scale tool.
I rotated the spine section each so that the character leans and bends using the Rotate tool.
I scaled the right leg section below the knee and ankle again along the X axis.
- 5.
Feel free to scale uniformly and see what happens. You can make one arm very huge or any part of body huge/small as per your 3D model.
Biped: Loading and Saving Figures
You have created a custom biped by tweaking the parameters in the structure rollout. You can now save the biped as a .fig file so that the same structure can be loaded in a different project. This saves the time of recreating the whole structure. Here are the steps to load/save a biped as a .fig for later use:
Note
You need to be in Figure mode to save and load .fig files.
- 1.
Create a biped from the systems rollout.
- 2.
Customize it to your liking using the biped structure panel or any other tools.
- 3.
Go to the motion panel in the control panel, under the Biped category.
- 4.
The icons are marked in red in Figure 5-7. The folder icon allows you to load an already saved biped, while the Save icon allows you to save the bip for later use.
Load and Save icons
Biped: Footstep Mode
- 1.
Create a biped and tweak the structure to your liking or alternatively you can load Biped_Walk_Start.max.
- 2.
Select any part of the biped and go into the motion panel.
- 3.Choose Footstep mode, as shown in Figure 5-8.
Figure 5-8Footstep mode
- 4.Footstep has many modes, so let’s look at each one at a time. Once you enable Footstep mode, you will get another rollout called Footstep Creation right below it (refer to Figure 5-9).
Figure 5-9Options in Footstep mode
The options are as follows:Create footsteps append: This option enables us to add footsteps following with any existing footsteps. Do so will cause the character to seamlessly transition from the existing footsteps to the new ones. Currently our file does not have any footsteps, so the Append Footstep option is grayed out.
Create footstep at current keyframe: Creates footsteps at the current frame your timeline is in.
Create multiple footsteps: This option provides us with a dialog box that helps us create a determined number of footsteps with varied parameters. We will look into this option later in this chapter.
Walk, Run, Jump: Whichever of these is selected will determine which animation is going to be created. If you wanted the character to do a jumping animation, you would choose Jump.
- 5.Now choose Create Footstep at the current frame:
The Walk Footstep option determines how many frames the biped takes in a single step.
Double Support is the number of frames in which both legs of the biped are on the ground.
- 6.
In any viewport (preferably top or perspective), click on the World grid to create a footstep. You can create multiple footsteps by clicking on the grid in the viewport. As you click, it will create footstep icons, which is where the character is going to step and move forward. Think about where you want the character to plant her feet and move forward and create the footsteps in that position.
- 7.
Note that the footsteps are numbered so that we can see which foot moves first. Note also that they are color coded. Green is the right foot and blue is the left foot.
- 8.
Once you have created enough steps, right-click to exit Footstep Creation mode. You can confirm that none of the footstep modes are selected in the footstep creation box.
- 9.
Individual footsteps can now be selected and moved to your liking, such as if you have placed them very far and want to tweak their position. Using the Move and Rotate tools. (See the reference file in the asset folder called Biped_Walk_Start_FootstepC.max.)
- 10.
If you scrub the timeline, you will see no animation happening yet. In order for your biped to follow the animation, use the next steps.
- 11.In the Footstep Operation rollout (refer to Figure 5-10), click on Create Keys for Inactive Footsteps button (marked in Figure 5-10). Note that the moment you click it, the biped repositions itself so that its leg is aligned with your first footstep. Note that you can still tweak the footstep by selecting it and moving it to a new position; the biped will adjust accordingly.
Figure 5-10Create inactive footsteps
Biped: Footstep Mode, Climbing Stairs
- 1.
Load Biped_Walkstairs.max or create a setup of stairs with a biped in front of them.
- 2.
Go into Footstep mode.
- 3.
Choose Walk, Run, or Jump, based on how you want the character to climb the stairs.
- 4.Click Create Footstep at Current Frame in footstep creation. Your footsteps are not going to align with the stairs, but create them anyway. See Figure 5-11.
Figure 5-11Biped footsteps on the World grid
- 5.Right-click to complete the Creation mode and use the Move tool to reposition the footsteps where they need to be. See Figure 5-12.
Figure 5-12Biped footsteps aligned with stairs
- 6.
Click on Create Keys for Inactive Footstep in footstep operation. Voila, you are done! Your character should be climbing the stairs as you scrub the timeline. The reference file called Biped_WalkStairs_StartComplete.max is provided so that you can see the complete file in action.
- 7.
As practice, create an obstacle course and see if you can make the character move around it.
Biped: Create Multiple Footsteps
Biped, Create Multiple Footsteps option
- 1.
Reset 3Ds Max from the File menu if you have another file open.
- 2.
Create a biped from the Systems panel and tweak it to your liking.
- 3.
Enable Footstep mode in the biped rollout.
- 4.
Choose your preferred style—Walk, Run, or Jump—in Footstep Creation mode. I chose Walk so the following options are for walking. You can follow along with Run or Jump as well, except there will be two changes to the parameters, which are mentioned in the last part of this section.
- 5.
Click on the Create Multiple Footsteps button, as shown in Figure 5-13.
- 6.A dialog box should pop up, as shown in Figure 5-14.
All the options here control how your character moves and gives varying options for varying values. We will discuss later what each value means.
The Create Multiple Footsteps dialog
Start Left/Start Right: Only one can be enabled. This determines which foot begins. In Jump mode, this won’t matter, as both legs go up at the same time. But the software needs to number the steps and whatever option is chosen gets the first numbering for the footstep.
Alternate: This mode cannot be tweaked in Walk mode, but it can be disabled in Run and Jump mode. If you disable Alternate in Run or Jump mode, the character will hop with one leg only, and the leg that will hop is determined by the Start left/right option. Try it out!!
Number of footsteps: This is the total number of footsteps that need to be created.
- Parametric stride width: This determines how spread apart the legs are during the animation.
- In Figure 5-15, the left biped has a default stride width value, which is 1, whereas the right has a stride width value of 3. Notice the difference.
Figure 5-15Parametric stride width of the left biped is 1 and the right value is 3
Actual stride width: Actual stride width and parametric stride width are connected. The actual stride width shows the distance between the two feet in the units as set in your file units and parametric always shows this in grid units.
Total distance: This option will show you to overall distance the biped has to cover during the walk based on the number of steps you give. Increasing or decreasing the number of steps will show how much are the biped will cover.
Auto timing: Enabling this affects a couple of parameters in the footsteps parameter—Walk Footstep and Double Support. Disable this and tweak the values if need be.
Interpolate: By enabling Interpolate, you will be able to add a value for the last step for the following parameters—Parametric Stride Length, Actual Stride Length, Actual Stride Height, and Time to Next Footstep. When interpolate is disabled, the options are grayed out. Enabling this will give a varied motion where the character begins walking based on first step parameters and ends with the last step parameters in the Create Multiple Footstep dialog.
Start after last footstep: Allows the multiple footstep dialog to use existing footsteps and append newly created ones to create a seamless transition.
Start at current frame: Creates footsteps from the current frame and does not consider any existing footsteps while creating them.
Actual stride height: Stride height should be 0 if you want the biped to walk in a straight line, using a positive number will make the biped take its next step that many units higher. A negative number can be used to simulate going down stairs. This is very easy to work with when you know the height of the stair.
Speed: Determines the units the biped will cover per frame.
Walk footstep: This determines the number of frames a footstep rests on the ground before going into the next step.
Double footstep: This determines the number of frames during one walk cycle where both feet will be in contact with the ground.
OK: Confirms the values and creates your footsteps.
Cancel: Closes the dialog box.
Defaults: Restores all the values to their defaults.
Play around with these values to experiment different Walk, Run, and Jump animations. The only parameter difference you see is in the bottom part of the dialog, where for Walk, it would be Walk Footstep and Double Support, which would be changed to Run Footstep and Airborne for a run cycle. The Jump dialog has the 2feetdown and Airborne parameters.
Biped: Animating a Biped
In earlier exercises, we created biped animations using Footstep mode. Now we will look at creating an animation from scratch by manually creating keys. For this exercise we are going to look at using the pose-to-pose method to animate a walk cycle. The walk cycle is going to be rough work and should give you an idea of the process.
- 1.
Create a biped and tweak it to your preferences.
- 2.
If you look at walk poses for animation, there are several reference images with five or more steps for a walk cycle. Figure 5-16 shows a rough image to give you an idea. There are detailed drawings with lifelike pictures available on the Internet.
- Note in Figure 5-16 that the first image and the last are the same. The second and fourth will be the opposite of each other but I provided variation in the sketch and the middle one is a unique pose. The first and last are called the contact pose. The second one, where the leg is firmly on the ground, is a down pose and the middle one is called a passing pose. The fourth one is called an up pose as the leg lifts up and the fifth is the same as the first.
Figure 5-16Rough poses of a walk cycle
We keep the first and fifth images the same so that our animation can be looped.
- 3.
Now let’s create these poses in Biped and animate them.
- 4.
Set the animation duration to 40 frames using the time configuration. We will animate each pose every 10 frames.
- 5.
If you have completed these steps, you can move to the next step. If not, a file called BipedAnimation_Start.max is provided with all the steps.
- 6.
Select one of your biped parts and go into the motion panel.
- 7.Expand the Copy Paste tab and close everything else. We need only this. See Figure 5-17.
Figure 5-17Biped motion panel, copy paste rollout
- 8.In the Copy Paste rollout, click on Create a Collection. This collection is going to have all the poses. Multiple collections can be created. Once it’s created, click on the col01 and type a name and press Enter. In the Copy Paste rollout, ensure that you are in Pose mode and not in Posture or Track mode. In my case, I am renaming the collection WalkCycle. See Figure 5-18.
Figure 5-18Motion panel, create collection
- 9.
Select the body parts and use the Move and Rotate tool to pose the character, as in the first person reference walk cycle.
- 10.Once you are happy with the pose (try to orient as many joints as possible to emulate the correct pose), click on the Copy Pose. A pose should be created. You can click on the name to rename it. Figure 5-19 shows a reference image of before and after creating the pose.
Figure 5-19Motion panel, create poses (left is before creating the pose, right is after creating the pose called Contact)
- 11.
When you create a pose, it is saved for future use in that file. Now let’s create the second pose, which is the down pose. It’s where the leg comes into contact with the ground.
- 12.
Once you are happy, create a new pose using the Copy Pose button and rename it to downpose.
- 13.
Now let’s move to the third reference, the pass pose. Repose the character accordingly and create another pose called the passpose.
- 14.
We are going to work with these three poses. So, why didn’t we create the fourth one? It’s the exact opposite of the second one and we are going to use 3ds Max’s built-in feature to create one for us.
- 15.
The BipedAnimation_poses01.max file shows all these poses.
- 16.
Now turn on Auto Key and go to frame 0.
- 17.Choose the contact pose from the list and click Paste Pose. Now your biped is going to get into that pose. Since our end frame 40 is the same pose, go to frame 40 and click Paste Pose again with contact pose selected. See Figure 5-20.
Figure 5-20Motion panel, Paste Pose
- 18.
Go to frame 10 and select the down pose. Choose Paste Pose.
- 19.
Go to frame 20 and select the pass pose. Choose Paste Pose.
- 20.Go to frame 30 and select the down pose. Choose Paste Pose Opposite. See Figure 5-21.
Figure 5-21Motion panel, Paste Pose Opposite
Frame 0 has a contact pose
Frame 10 has a down pose
Frame 20 has a pass pose
Frame 30 has a pass pose (the pasted opposite)
Frame 40 has a contact pose
Now play the animation to see the result. This is a rough block out animation. A completed file is in the content directory called BipedAnimation_roughblock.max.
So far we have learned to create and customize bipeds and use the character studio tools to make them walk, run, and jump. We also learned how to create an animation manually by creating keys. You might wonder if you use the biped animation from the Footstep mode to tweak the animation. Yes, you can, and that is what we are going to look at next.
Biped: Animation Layers
Let’s use the power of layers to add more dynamic realism to a walking biped.
- 1.
Create a new scene with a biped.
- 2.
Get into Footstep mode.
- 3.
Create a series of footsteps.
- 4.
Apply the footsteps by creating keys for inactive footsteps.
- 5.
Alternatively, you can load the BipedAnimationLayers_Start.max file.
- 6.Now let’s say we want the biped to look around as it walks. Using the Set key, you can set the keyframes for the head; however, in most cases, this will result in weird, unpredictable movements. The right approach is to drop out of Footstep mode and then go into the Layers panel. See Figure 5-22.
Figure 5-22Motion panel, animation layers
Note in Figure 5-22 that there is one layer by default, which is named original. This layer will have all the keys of the walk that we created.
- 7.Click on the Create layer and then click to rename it.
Figure 5-23Motion panel, Create Layer
- 8.
Now turn on auto key and tweak the parts as need. In this case, we will animate the head to turn around and look as it walks.
- 9.
Now play the animation. You should see that the character looks around and walks, thereby merging two animations from two different layers. At any point if you do not want that layer, you can delete it. You can restrict the visibility of the animation from that layer by inputting keyframe numbers.
- 10.
A reference file called Biped_AnimationLayers_Complete.max is available so that you can check the result.
Biped: Motion Flow
Motion flow is useful when you have multiple motion files saved and want to blend them so that the transition is smooth. In this exercise, I am going to use the bip files I saved using Footstep mode. There are a total of three bip files in the content directory; free to use any downloaded from the Internet to follow along.
- 1.
Fire up 3ds Max.
- 2.
Create a biped and tweak it your liking.
- 3.Click on Motion Flow mode, which is the icon next to Footstep mode. See Figure 5-24.
Figure 5-24Biped, Motion Flow mode
- 4.Now you should have only two rollouts—one is the biped and the other is the motion flow. Click on the Show graph in the motion flow rollout, as shown in Figure 5-25.
Figure 5-25Motion Flow, Show Graph invoker
- 5.The Motion Flow Graph will load, as shown in Figure 5-26.
Figure 5-26An empty Motion Flow Graph
- 6.In the Motion Flow Graph, click on the new clip. Click three times on the motion flow graph viewport to create three clips, as shown in Figure 5-27.
Figure 5-27Motion Flow Graph with three clips
- 7.Right-click on each clip and browse to the bip files provided in the bip_motion folder. Feel free to choose your own bip if you have any downloaded from the Internet. See Figure 5-28.
Figure 5-28Clip loader
Do the same thing until you have all three clips with the bip file loaded. The bip filename will replace the clip 1, 2, and 3 names.
- 8.
Now click the Define Script button in the Scripts section of the Motion flow rollout. The Define Script is located below the show graph in the motion panel.
- 9.
Feel free to rename it if you want to; I leave it at the default name.
- 10.Now, with the Motion Flow Graph Editor open, Click on the clips in the order you want them to animate. Your script interface should look similar to Figure 5-29.
Figure 5-29Motion Flow 3ds Max UI
- 11.
Ensure that you have enough frames to play all the animations.
- 12.
Note that transitions between the clips are seamless.
- 13.
A completed file called Biped_Motionflow.max is provided in the content directory.
Summary
To summarize, we can create poses and convert poses to animation and save them to load them later and create transitions. The possibilities are limitless with these tools. Biped is far more powerful and capable than explained in this chapter, but this should get you started.
We haven’t animated a character with the animation yet. We will look at attaching a character to the biped after we cover a few more tools. Practice and practice a lot until the animation “timing” and use of tools becomes second nature to you. This is the key to success! In the next chapter, we look at another tool, called the character animation toolkit or CAT, rigs (not the animal cat).