One of the things I struggled with when I was an animation student is constraints. Not having a good grasp of constraints in Maya and adequate technical planning slowed my work down tremendously. It’s also frustrating to deal with constraints issues as I’m animating.
Thus, I wanted to write this blog series on constraints so that everyone who is new to animation or needs a revision to constraints can benefit from this information and be more efficient with their shots.
Here’s the part 1 of the series. Enjoy!
What Is Constraint and Why You Need It?
When I was a student, I tried to avoid using constraints in my assignment the best that I could. But it’s impossible! Most animation shots require you to interact with some kind of props and the environment. If you don’t use constraints in your assignments or you work, you either:
A) find it very difficult to animate what you have in mind, or
B) limit what you can do in your shot.
I would always realize that I need constraints after I started animating. Not good.
According to Maya User’s Guide description,
constraint let you constrain the position, orientation, or scale of an object to other objects.
Further, with constraints you can impose specific limits on objects and automate animation processes.
The keywords here are “automate animation processes”. It should make your life as an animator easier, not harder.
But before you even learn how to use them, you should understand what they are capable of doing. It will save you some time in the future doing unnecessary animation which Maya can already help you do.
What Can the 11 Different Types of Constraints Do?
Up till the week before, I didn’t get why are there so many different types of constraints in Maya and what do each of them do. There are 11 types of constraints in Maya, but I only use one – Parent Constraint.
What are the other 10 constraints for?
After doing some research, I realize that the other constraints are used by riggers or used for animating uncommon actions like teardrops or sliding down a hill. Parent constraint is mainly used for holding and releasing of props. That’s what animators normally have to animate and that’s why we are more familiar with the parent constraint.
Below is a summary of all the constraints.
First 5 Constraints: Attribute Constraints
I group the first five constraints as attribute constraints because the attributes (i.e. translate, rotate and scale) of the child object follows the parent object.
Other than the aim constraint that have the child object aiming at the parent object, the other four constraints have the child object take on the same attributes as their parent object. For example, if you +5 to Tx for the parent object, the child object will also +5 for its Tx.
The table below shows what attributes are controlled by the parent.
So for the point constraint, only the translation values of the child object will follows the parent object. Not the rotation values. That’s the reason why we use parent constraints more often. It has the best of both worlds, translation and rotation.
You can see which attributes of the child object follows the parent object by looking at the child’s channel box. The attributes that are constrained as highlighted in blue.
If you are interested to learn more about these five constraints, you can watch the video below. Although the video is for riggers, it’s pretty informative for animators too. After watching the video, I finally realized know what aim constraint is used for. It’s used to make the eyeball controllers for the rigs.
Next 5 Constraints: Object Constraints
The next five constraints are what I call object constraints because instead of following the attributes of the parent object, the child object “sticks” to the parent object.
Other than the point on poly constraint which has the child object literally stuck onto the parent object, the child object for the other four constrains can still move across the surface and contour of the parent object.
Don’t get what I mean? Watch the video below.
With geometry constraint, imagine what you can do. You can animate:
- a ball rolling off a hand,
- a teardrop flowing down the face,
- a roller coaster ride,
- a sledge sliding across uneven snow surfaces, and
- a person stringing a bead necklace.
The possibilities are endless!
The closest point constraint is similar to the geometry constraint. The difference is that it creates a pair of locators. Instead of having the child object “sticks” directly onto the parent object. You can constrain the child object to the locator and use the other locator to control the movement across the parent object.
Maybe the video below will give you some idea what this constraint can do.
The point on polly constraint is also a very useful constraint. One of my friends taught me this and I used it during production. If you have a character or an object stuck onto another character or object that squashes and stretches a lot, use point on polly. It’s very effective.
Last Constraint: Pole Vector Constraint
The last constraint is pole vector constraint. As the name suggests, pole vector constrain is used to control the pole vector. It is used to create PV controllers for the knees and the elbows.
I hope that this post gives you more ideas on how you can use constraints for your animation. On the next post in this series, I’ll be sharing the differences between parent and parent constraints, and how you can remember their differences better.