Understanding Dynamics - the Powerful Effects That Can Make Your 3D Life Easier
Dynamics are an extremely powerful feature in any 3D application. Without them there would be no particle effects like smoke and fire or complex cloth simulations. It's no surprise that mastering dynamics is a vital step in your 3D skill set. They can make your life easier, and greatly increase the speed at which you work. This article will help you have a better understanding of dynamics so you can use them confidently in your next project. Dynamics are a complex physics engine inside your 3D application; dynamics describes how objects move using rules of physics to simulate real-world forces. You can specify the different actions you want your object to take, and the software will figure out how to animate that object in the most realistic way. Dynamics are vital for creating realistic motion that would otherwise be extremely difficult and time consuming to achieve with traditional keyframe animation. For instance, you could use dynamics to simulate a puck bouncing around in an air hockey game or a building toppling over into a pile of rubble. While simulating an air hockey puck may not seem very interesting to you, the different effects that can be created in your 3D application with dynamics are substantial, everything from realistic fluid effects to explosions, smoke, fire and more. Chances are the last blockbuster movie you saw utilized dynamics to create some of the special effects. Without dynamics most of the jaw-dropping 3D effects you see wouldn't be possible. Working with a complex physics engine may seem daunting, and an understanding of physics might seem paramount, but in actuality you do not need to be a physics genius to create these types of simulations. Dynamics are a type of animation simulation but they differ in how they are calculated in the computer. Typically dynamics are calculated from frame to frame, and the position of an object in each frame is taken from the position of the previous frame. This differs from keyframe animation where the object's position is determined by key values set at different frames. You can, however, bake out your simulations into regular keyframe animation, which will allow you to edit the simulation with the use of keyframes on the timeline. Key Dynamic Features If you've ever had the challenge of animating a collision, or any object that needs to feel like it's obeying the laws of physics, you know it can be extremely difficult. Something as simple as a dice rolling on the table can take hours of tweaking keyframes to get it to look natural. Dynamics have the ability to quickly and easily simulate this type of animation with what is called a rigid body, whether it's a line of dominoes falling or a wrecking ball demolishing a brick wall. If you were to animate each brick crumbling or each domino falling, it would be a giant task but with rigid bodies it can be simulated by the computer in a realistic way in a fraction of the time. Rigid bodies are great for simulating animations that would otherwise take much too long with traditional keyframing. Most 3D applications have built-in effects great for quickly dropping down an effect that will produce very nice results. For instance, Softimage, Maya, and 3ds Max have built-in fire effects that can be emitted from any polygon or NURBS object. Play around with these effects in your 3D application to see how they work; each one has different attributes that can be fine tuned to adjust everything from fire strength, emission, direction and more. There are also many other pre-built effects like smoke and lighting. Another great feature with dynamics is the ability to simulate cloth. With Maya you can quickly simulate a cloth material from any polygon object with nCloth. Whether you want to create clothes that move and flow properly around your character, or a table cloth for a dining room this can be achieved with nCloth. In 3ds Max this is called Cloth, and Softimage simply calls it Cloth as well. Keep in mind that working with a cloth simulation can use a lot of computing power. Even with a fast computer, cloth dynamics at a high level of accuracy can take a very long time to process, so you may need to lower your simulation to a reasonable level. One of the most powerful features in a dynamics system is particles. Particles can be used to replicate fire, explosions, smoke, water, fog and more. While the built-in effects that come in most 3D applications are great, particles allow you to fine tune the effects and have complete control over your dynamic simulation. Particles can also be used to create things like grass and fur. The particles are controlled by an emitter which acts as the source of the particles; the emitter has many different attributes attached to it, like particle emission rate, velocity and many other settings that can be tweaked. Unlike the built-in effects, particles do not produce the desired look right at the start, and will need to be adjusted to create the look of the effect that you want. What to Expect When Working With Dynamics When working with dynamics there is inevitably going to be a significant amount of trial and error. The result you are looking for will not be achieved with the click of a button. Even with pre-made effects like the fire effects, there will most likely be editing that needs to be done in the effect's attributes, in order to get exactly what you are looking for. When working with dynamics, the typical workflow is tweak and test. Do not get discouraged when you aren't getting the results you want right off the bat. What you see in the viewport isn't always what you get. When played back, complex dynamics can give undesirable results or be slow all together, because the computer has to calculate everything on the fly. To get a better representation of the dynamic simulation happening, you can do a quick playblast or animation preview depending on your software. Dynamics are an amazing tool to have at your disposal, and can make many tasks much easier for you. Whether you need to simulate an object ripping through geometry or a wall being demolished, dynamics can achieve it quickly and in a believable way. To learn more about dynamics, check out these in-depth tutorials on Introduction to Dynamics in Maya, Introduction to MassFX in 3ds Max, and Beginner's Guide to ICE in Softimage. Find more training options with more 3D dynamics tutorials.