Constraints are used to restrict an object's motion. After you apply constraints, they are connected to the object they're associated with. Maya includes the following constraints:
- Nail Ties an object to a point in the scene. The object behaves as though it's tethered by a solid rod, but it can orbit anywhere around the tie point as it collides with objects or is affected by fields. You can not use a Nail constraint on a passive rigid body.
- Pin This type of constraint requires two objects that are tied together to a separate pivot point. You can use a pin constraint to create effects such as link in a chain or robotic arm.
- Hinge As the name implies, you get free rotation constrained to an axis. You can make active objects hinge to a point in space, to another active object, or to a passive object.
- Spring This constraint is similar to the Nail constraint, but it also has a telescoping characteristic that allows it to extend its length. As with the Hinge, you can use the Spring to tie an active object to another active object, to a passive object, or to a point in space.
- Barrier Blocks objects from going beyond a planar boundary. You can assign this constraint to only one object. Objects can deflect, but not bounce, from the Barrier constraint, so it's recommended for objects that block other objects, such as walls or floors
Particles can be particularly helpful when you want to create and animate dozens, hundreds, or thousands of similar objects that vary slightly in their geometry or animation. You can also use Maya's Dynamics mode to simulate reality in how objects behave—for example, animating the way bowling pins react when struck with a bowling ball. Another feature in Maya's Dynamics mode is the ability to create "soft-body" effects, in which objects deform as though they were made from rubber or gelatin. Dynamics and particles—work together to create animation. With rigid-body dynamics, the idea is to simulate physics so that objects collide with each other and deflect. With soft-body dynamics, objects change (deform) as a result of their collisions. With particles, you can easily control the animation of large numbers of objects.
What are Particles
A Particle object is a collection of particles that share the same attribute. In maya , Particles are points you display as dots, streaks, spheres, blobby, surfaces etc. You can animate the display and movement of particles with various methods, for instance, Keys, expressions, and field such as gravity. Particles are ideal for animating difficult effects, such as explosions, swarms of bees, and galaxies of stars.In maya, we use particles for creating special effects.
To create particles in your scene, you can use drawn particles or particle emitters. To paint particles in your scene, choose Particles > Particle Tool > option box. Another method called Particle Grid is available, which you use to define the corners of a 2D rectangle that's filled with particles. Particle grids can be helpful for visualizing the effect of fields as you create them.
In Maya, the source that particles emanate from can be many things.
Point - omni An emitter that sprays particles from a point in all directions.
Point - directional An emitter that sprays particles in a linear or conical direction from a point.
Volume Particles are created from multiple points within a defined volume, which can be a cube, sphere, cylinder, cone, or torus.
Surface You can define one of your scene's NURBS or polygon objects to create particles from its surface.
Curve Any NURBS curve can emit particles.
Animate the Particles
You can animate particle motion in several ways.
Set the position, velocity or acceleration attributes of particles. You can set keys to animate an entire particle object's translate, scale and rotate attributes.
Apply fields , such as gravity to particles.
Turn geometry into a collision object and bounce particles off it.
Make the particles follow a moving goal object.
In Maya, there are two types of particles: hardware rendered and software rendered. Hardware particle render much faster using your graphics card's on-board hardware. Hardware particle types must be rendered with the hardware-rendering system (Window> Rendering Editors >Hardware Render Buffer), because the particles don't appear in the normal software render.
The Hardware Render Buffer has an option for masking any particles that fall behind scene objects. Another issue is that, by default, hardware rendering looks jagged . Maya handles ant aliasing similarly by multisampling in the Hardware Render Buffer, which is enabled by choosing Render>Attributes on the Hardware Render Buffer menu.
Point The default particle type, designed to render as a spot. You use the render settings in the Hardware Render Buffer, under Render> Attributes.After you add attributes for a particle render type, you can change the render type and add its default Particle Render Type attributes.
Multipoint Like the Point particle type, but creates clusters of points to get a denser, clumpier appearance.You can use this render type to create dust, cluds,most or other gaseous emissions.
Streak Similar to the Point, but creates a streaking line instead of a dot. This type does not render until the particles are moving and you attempt to hardware-render a frame with particle motion. The Streak length is based on the velocity of the particles, so if the particles are stationary or moving slowly, you won't see the particles.
Multistreak Like the Streak particle type, but creates clusters of streaks to get a denser look.
Sprites Render type lets you display a texture image or image sequence at each particles.Each particle can display an identical or different image.Asprite appears as a small rectangle until you map a texture image to it .
Spheres These are three-dimensional spheres and render type displays particles as opaque spheres.
Numeric This particle type displays a number for each particle. It's particularly useful for troubleshooting stray particles.By default, Maya displays particle ids for the numeric render type.
Hardware-rendered particles cannot cast shadows or appear in reflections or refractions:
The following particle types render as part of your scene when you render a frame. They are able to reflect, refract, and cast shadows.
Blobby Surface A particle form of metaballs, the blobby surfaces look like spheres until they approach another, at which point they reach for each other like drops of mercury. They appear only in software rendered images.
To set Blobby Surface render type
Select the particle object. In the attribute editor ,set Particle Render Type to Blobby Surface. Apply a shading group to the particle object and then add a light to the scene. Software render the scene.
Cloud The cloud render type displays particles as blurred or cloudy metaballs. This particle type works specifically with the Particle Cloud material type and doesn't render with typical object "surface" materials.
Tube As the name implies, the source object type is a kind of uncapped cylinder. You can define the radius at the two ends and renders only with volumetric material types .
Instanced Geometry If you want to have an object stand-in for the particles, you should use Maya's Instancer, which enables you to use any kind of geometry or textures you like.
AddingReflctions, Refractions and shadows to Software - rendered particles
Select the particle object. In the attribute editor turn on---visible in reflections, visible in refractions and cast shadows.
Any particle system can collide with any scene geometry, but you have to set each collision up separately. To do so, you select the particles, Shift-select the geometry they will collide with, and choose Particles > Make Collide. The particles then collide if they hit the object.
Particles can also be set to have goals, meaning that the particles try to move to a specific configuration, shape, or location. You can create goals by selecting the particle object you want to be affected by the goal. Shift-select the object you want to