BlenderArt Magazine » Blog Archive » Animating A Robot Tutorial

Let’s Get this Robot Moving: This tutorial assumes you have already modeled your robot, “Papero”. I have done a few preliminary tasks to make this tutorial easier to follow:

For animating we will take the Papero model we made in the modeling a robot tutorial.

Step 1.
• I assigned basic materials to the separate parts so that they are easier to distinguish (if you have already followed the texturing tutorial, that is fine)
• I have rotated the head to face straight forward.
• I have also turned off subsurf for now (makes it easier to see what you are doing). (fig 1)

Image 1

With simple characters, such as our robot, you don’t need a lot of complicated movements. In fact you could probably get away with just using simple keyframing of his head moving from side to side, and adding additional keyframes as he changes location. But then this would be a very short tutorial, and rather unnecessary as you could figure that out all by yourself.

The fact that Gaurav modeled “Papero’s head as all separate parts, presents us with an interesting option for giving our robot an interesting action set. We are going to animate the ear rings and ear ball shooting out from the side of his head as he rolls along. We are going to accomplish this by using Action Constraints.

The basic premise of Action Constraints is simple. You create a set of actions once, then attach that set of actions to one bone with an Action Constraint. When you rotate the one bone, the set of actions gets triggered. Pretty slick time saver, it also assures that the action will be consistent throughout your animation.

This tutorial was created with Blender 2.40 alpha-2. (If you have a previous and or possibly newer version, this should not be a big problem as Action Constraints have been around for quite a awhile.)

So let’s get started.

Step 2. We need a basic armature. There will be no IK chains or anything fancy.

• Place your cursor below the robot.
• Spacebar > Add > Armature. This will be the Root bone and will be used to move the entire robot. (fig 2)

Image 2

Step 3.
• Next place your cursor in the bottom section of the robot, about even with the wheels
• Spacebar > Add > Bone. This will be the Wheel Base bone, and will be parented to the Root bone. (fig. 3)

Image 3

Step 4.
• Next place your in the main body section, Spacebar > Add > Bone, this will be the Body bone, and will be parented to the Root bone.
• Tab out Edit mode and RMB on the robot head, in the Edit buttons click on the ‘Center New’ button, Shift + S > Cursor > Selection. (fig. 4)

Image 4

Step 5.
• Press ‘A’ key to deselect all, RMB on the Armature and Tab back into Edit mode.
• Spacebar > Add > Bone. This will be the Head bone, and will be parented to the Body bone. (fig. 5)

Image 5

Step 6.
• Zoom in on the ear rings, place your cursor in the first ring, Spacebar > Add > Bone. This will be the Ring 1.L bone, and will be parented to the Head bone.
• Place your cursor in the second ring, Spacebar > Add > Bone. This will be the Ring 2.L bone, and will be parented to the Head bone.
• Place your cursor in the ear ball, Spacebar > Add > Bone. This will be the Earball bone, and will be parented to the Head bone. (fig. 6)
• ‘B’ key, drag a box through the ear ring and Earball.L bones, ‘Shift + D’ key to duplicate them, Control + ‘M’ key to mirror them, drag them to the other side of the head and line them up with the ear rings. (Names will be the same, except will end in ‘R’.)

This completes your armature.

Image 6

Step 7. Now we need to parent our robot to the armature.

• Tab out of Edit mode, press ‘A’ key to deselect everything.
• Select (RMB + Shift key) all the robot pieces, then select the armature
• Control + ‘P’ > Armature
• Choose ‘From Closest Bones’

Now comes the fun part, double checking to make sure all the parts assigned to the correct bone, no help for it, so let’s get to it. The steps will be the same for each part.

• Select part, Tab into Edit mode, ‘A’ key to deselect all vertices, look at the ‘Vertex Group’ panel
• Scroll to the correct bone for the part you are checking, click the ‘Select’ button. If all goes well, the right vertices will turn yellow. (fig. 7)
• To assign vertices to ‘Vertex Group’, select vertices wanted, scroll to desired bone in list, click ‘Assign’ key
• To delete vertices from ‘Vertex Group’, select vertices wanted, scroll to desired bone in list, click ‘Remove’ key

Make sure you test your robot in Pose Mode, select each bone and rotate/grab to ensure everything is moving properly. In Edit mode, select all bones and press ‘Control + N’ to recalculate bone roll (otherwise you might get strange results).

Image 7

Step 8. Now we can start setting up our actions. Split your screen into 2, with 3d view on one side and Action Editor Window on the other (fig. 8 )

Image 8

Step 9.
• Select the Armature, Control + Tab into Pose Mode (Armature bones should be blue/green depending on selection status)
• Select the 3 ear bones (Ring 1.L, Ring 2.L & Earball.L), ‘I’ key > LocRot, this will be the base point in the action.
• Go forward 40 frames, ‘I’ key > LocRot, this will be the end point in the action.
• Go back 20 frames
• Select the Earball.L bone, ‘G’ key, while holding down the ‘Control’ key, move the Earball.L 3 units to the left. ‘I’ key >LocRot.
• Select the Ring 2.L bone, ‘G’ key, while holding down the ‘Control’ key, move the Ring 2.L 1 unit to the left. ‘I’ key >LocRot. (fig.9)

Image 9

Step 10.
• Go back to frame 1 and test your new action by pressing ‘Alt + A’ keys.
• In the Action Editor Window, rename your action something relevant, like “Ear action”, close the action (click the ‘X’ next to the action name)
• Add a bone above the head (Spacebar > Add > Bone), name it Ear Mover, parent it to the Root bone, so it doesn’t get lost when moving the robot around a scene.
• Select Ring 2.L bone and add an Action Constraint in the Constraint panel. Fill in the following settings to match the image. (fig. 10)
• Repeat for Earball.L

Image 10

Step 11. Now when you move the Ear Mover bone, the Ring 2.L bone and the Earball.L bone will move through their action. (fig. 11)

Image 11

At this point you can go back to your Ear action and add in actions for the right side of the robot, so that both sides pop out at the same time. After you have added in the new actions for the right side, don’t forget to add action constraints to the right side Ring 2.R and Earball.R bones.

At this point ‘Papero’ is ready to roll. He can be keyframed to move across the screen, bump into things and show surprise (his ears popping out).

To practice on you own, here are some further suggestions on actions you can add to our little robot ‘Papero’ to give him a little more character:

• Make his head pop up a little off of his body
• Make his body pop up a little off of the wheel base
• Have Ring 1 and Ring 2 rotate slowly back and forth while he is rolling through scene.
• Have the Earball slide ever so slightly in and out of rings
• Move Head back and forth sideways as if he is scanning his surroundings.

Have fun with your new little robot.

References & External Links

• .blend file

• Modeling A Robot

• Texturing A Robot

Written by Sandra Gilbert (aka dreamsgate)

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