Firstly if you have noticed, I have yet to blog about wk 12’s lesson.Don’t worry! Calvary is on the way, I will upload it within the next hour after this post.
So in Wk 13 we will be working on a animating a 3D object, in this case a mechanical arm using skeletons. This process of animating the skeletons is called rigging.
In this tutorial we will learn a few main things, they are:
- Hierarchy
- Creating a skeleton
- Inverse Kinematics
- Parenting and constraints
- Hierarchy: This tutorial uses a lot of the hyper graph to view our object’s hierarchy.The hierarchy of our model shows which part of the model is controlled by which other part. In essence it allows us to see which object is a parent or child of other objects. It also allows us to see nifty little tricks such as the effector of an ik handle and so on. It’s a giant flowchart of how the animation object works.
- Skeletons: Are basically well… skeletons, they are the support structure for your animation object just like how skeletons work on the human body. Skeletons also have joints, which determine the movement scale of your animation object.In this case our animation object is the mechanical arm, and this is how it’s skeleton look like.
- Now that we have the skeleton, we need to bind the flesh to it, so that we can have an animation object. Now I’m using flesh as a metaphor so in this case we will parent the joints to arm 1-4(the skeleton).
Inverse kinematics is a subdomain of kinematics, which is of particular interest in robotics and (interactive)computer animation. In contrast to forward kinematics, which calculates the position of a body after a series of motions, inverse kinematics calculates the motions necessary to achieve a desired position.
Using the IK handle tool we can assign which joints have the IK properties applied. Using the IK handle tool, will select the closest skeletal joint wherever you have clicked on
Parenting & Constraints:
Parenting basically is the same concept that we have learnt in programming. The object to be parented to is the child, while the other object is the parent.The child object inherits the values of the parent. Always shift select the child before shift selecting the parent object before parenting(shortcut P).
Constraints like the word infers, constraints the object to a certain XYZ value be it translate or rotate. Using constraints we can limit the movement of an animation object so that it does not go out of bound(eg you can’t rotate a human head 360 degrees ) so we constrain the head to rotating 180degrees.
Below is a video on my mechanical arm model, I will explain more about some of the features that I have described above. Fast forward to the last few seconds to view the working animation!
Cheers
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Jasper Phua Kai Wen
Games Entertainment Tech
C260
Temasek Polytechnic
