The Wonderful World of Constraints

Have you ever tried to animate a character that's interacting with objects in your scene but you were stuck on where to begin? A majority of animated sequences include some sort of interaction with a prop or several props. Animating such interactions can be quite challenging, and much planning and focus is usually required for it all to look convincing. Here are some time-saving techniques to help you animate prop interactions. If and when you must animate a prop interaction, you should first ask yourself a couple questions in order make sure you’re using the most efficient workflow possible:
  1. If a character intends on picking up, using and then dropping this prop, given the circumstances of the shot, what is the best way to attach the prop to the character?
  2. Will the prop be passed to multiply characters or will it remain with one?
446_MASTER Once these questions are answered, you can then decide if the prop should be parented or constrained to the character. More often than not, you'll find that constraining the prop is the best route to take. Constraints offer way more control and include many more features than parenting ever could or will! That's why it's vital that you familiarize yourself with this helpful toolset so that you can not only achieve realism when a character interacts with an object, but also animate such a performance in the most convenient way possible. Constraints connect an object's translation, rotation and/or scale to one or more objects, allowing you to turn the control on and off via a built-in weight property that regulates how much influence it has over the object's transformations. In animation, this can be extremely useful when a performance calls for a character to interact with an object in an environment for a certain period of time, before letting go of the object. 55_MASTER Consider a character that will pick up a sword and defend itself against an attack. In this instance, you can wait for the moment when the weapon is gripped to constrain it to the character’s hand, and after the character has managed to save the day, or at least save itself, with the help of the prop, and is ready to throw it down triumphantly you can deactivate the constraint. Deactivation will no longer cause the prop to be driven by another source, giving you full control to animate it as you please, falling from the hero or heroine’s hand. Or, if the weapon, sadly, gets snatched from the character, you can constrain it to the hand of the one responsible for such a devious act, and use the constraint’s weight to help seamlessly transfer the prop from one hand to the next. This is just one of many circumstances when a constraint can be used to help you improve your animation workflow. What’s even better is that most, if not all, 3D animation programs offer several types of constraints you can choose from in order to animate object interactions using methods that would be most suitable for your needs. 444_MASTER There are constraints that let us attach objects to follow a surface’s deformations. There are constraints that can cause an object to target, or aim at, the position of another object, which comes in handy when animating eyes. There are also constraints that can be used to quickly animate an object along a trajectory, or path, making vehicular animations much less of a hassle since you get to design this trajectory that the vehicle should travel along and choose its timing along the path. These are just a few of the many constraints you can utilize. With so many to choose from, there’s a high chance that you’ll be able to find the constraint that will help your animation process be a more efficient one. Get a grip on how your characters interact with objects with more animation constraint tutorials.