Publishers of technology books, eBooks, and videos for creative people

Home > Articles > Digital Audio, Video > 3D

  • Print
  • + Share This
This chapter is from the book

This chapter is from the book

Common Particle Parameters

Each class of particle system in 3ds max 4 has a common set of parameters that are used to control aspects of the particle system.

The following sections describe the parameters common to each class of particle system, both Simple and Super.

Simple Particles: Spray and Snow

Spray and Snow share most parameters; Snow particles have rotation parameters and Spray particles do not. The following are parameters for the Simple Particles:

  • Viewport and Render Count. These parameters control the total number of particles that are emitted over time with regard to viewport display and render display. The main purpose for these related parameters being uncoupled is that the user can work faster in the viewports by displaying only a portion of the total particle count, while still rendering with a full quantity.

  • Drop Size. This parameter controls the scale of the particle geometry.

  • Speed and Variation. These are a bit misleading. Speed determines the velocity of the particles at birth, and Variation not only varies the speed value but also implements a sort of spreading pattern, with higher values increasing the spread.

  • Tumble and Tumble Rate. These are rotational parameters added to Snow. Tumble controls the amount of rotation of the particles and Tumble Rate controls the speed at which the particles rotate.

  • Render Tetrahedron and Facings. These parameters are the given particle primitives or predetermined geometry for the particles. Tetrahedrons are shaped like simple raindrops, and Facings are square polygons.

  • Start and Life. These parameters control particle birth and death. Start determines the start frame of particle emission in absolute time, and Life is a relative value that determines how many frames a particle is "alive." Life is relative, because particles are constantly born and emitted, starting on the Start frame and continuing forever, so a particle born at frame 100 with a life of 60 dies at frame 160.

  • Birth Rate and Constant. These parameters are used to pulse or burst emit particles, a simple method that is expanded by the Super Particles. Birth Rate determines the amount of particles emitted in a given round. When activated, the Constant check box disables the Birth Rate parameter.

Super Particles: SuperSpray, Blizzard, PCloud, and PArray

The Super Particles class of particle systems share many common parameters. In fact, SuperSpray, Blizzard, PCloud, and PArray are primarily differentiated by how they handle emitters. The following are parameters for the Super Particles:

  • Icon Size and Emitter Hidden. These parameters are cosmetic values that control the size of the emitter icon and determine whether it is hidden or displayed.

  • Dots, Mesh, Ticks, and Bbox. These parameters are the viewport display methods for particles. Dots vary depending on the viewport display method used (Heidi dots are single-pixel and OpenGL dots are much larger). Mesh displays the actual geometry to scale in the viewports, a method that tends to be computationally intensive but still useful. Ticks, like Dots, are constant in size with the exception of being shaped like crosses. Bbox displays the bounding box of the particle geometry. This is often faster than using the Mesh method.

  • Percentage of Particles. This parameter controls the percentage of actual particles displayed in the viewports. This does not affect the quantity of particles at render time, but is used to speed up display by reducing the number of particles the display has to render.

Particle Generation

The Super Particles class was added in release 2 and builds on the previous particle systems, Spray and Snow. The main difference between the four Super Particle systems is the way in which they emit particles. Common particle generation parameters are as follows:

  • Use Rate and Use Total. These parameters are the primary methods for controlling the amount of particles emitted. Use Rate determines a variable number of particles that are emitted at each frame. Use Total defines a total quantity of particles that the system can emit over time, the rate of which depends on the emission start and stop time.

  • Speed and Variation. These parameters control the emission velocity of the particles. Variation controls the percentage at which Speed will be varied on a particle-by-particle basis. You use Variation as a common parameter with many particle systems because it's useful to break up the uniformity of values by adding some randomness to them.

  • Emit Start and Stop. These parameters are the set frame numbers at which particles will start to be emitted and will stop.

  • Display Until and Life. These parameters are used to determine when particles will die. Display Until is a rudimentary way of doing this absolutely so that on a given frame all particles will die. Life is like Spray, a relative value determining how many frames a particle will be present after it's been emitted.

  • Size, Grow For, and Fade For. These parameters control particle geometry scale. Size is a multiplier of scale and has a Variation parameter tied to it to randomize the scale on a particle-by-particle basis. Grow For and Fade For are two parameters that cause particles to grow from a scale of zero to the full Size value and then fade to zero over a given set of frames.

  • Seed. This parameter is an important random value that controls the uniqueness of particle systems. It's a random number that can be changed using the New button next to it. If multiple particle systems use the same Seed value, they emit particles identically. Use different Seed values to cause variation among particle systems.

Particle Types

The Super Particles class of particle systems shares three main types of geometric representations: Standard, MetaParticles, and instanced geometry. PArray contains a fourth type called Object Fragments.

Standard, MetaParticles, and instanced geometry determine the types of geometry the particles will be displayed as:

  • Standard. This type offers several particle primitives, such as Triangle, Cube, Facing, and Sphere.

  • MetaParticles. These are a special type of geometry primitive that is useful in creating amorphous liquid shapes. MetaParticles create spheres at each particle location, and then fuse the geometric surfaces together when their proximity to one another passes a user-defined threshold. When MetaParticles are sparsely spaced they appear as simple spheres, but when packed closely together they fuse into blob shapes. This is computationally expensive and should be used with extreme care.

  • Instanced Geometry. This is a useful particle type that enables the user to reference separate objects in the scene as particle geometry. For example, a single teapot object can be referenced and will cause instances of the teapot to be emitted as particles. The instanced geometry can also be hierarchically animated, enabling effects such as swimming fish and flocking birds.

Rotation and Collision

All the Super Particles share the same set of Rotation and Collision controls, which specify the speed of rotation and starting angles. Collision is a bit misleading, because it has to do with particle-to-particle collisions only, not with objects in the scene. The following are Rotation and Collision controls:

  • Spin Time and Phase. These control the amount of frames it takes for a particle to fully rotate, with low values causing faster spinning. Phase determines the starting angles of rotation.

  • Random, Direction of Travel, and User Defined. These are three methods for controlling rotation. Random rotates the particles on varied axes. Direction of Travel forces the particles to orient themselves in the direction they are traveling, with an optional Stretch value to actually stretch the particle geometry based on velocity. User Defined sets an absolute rotational axis in X,Y, and Z.

  • Interparticle Collisions. This is a set of parameters to test particle-to-particle collisions. This is computationally intensive and useful only in rare instances. Calc Intervals Per Frame is a parameter for controlling the rate at which the particle collisions are tested. Bounce is a percentage of force applied at collision.

Object Motion Inheritance

Object Motion Inheritance controls how much velocity is passed from the emitter to the particles. No motion inheritance causes the particle's speed to control velocity; 100% inheritance causes the full velocity of the emitter to be added to the particle emission speed. This is relevant only to a moving emitter. Object Motion Inheritance is a useful control for adding realism to particle motion. Unfortunately, the default value of 100% tends to confuse people. There are two controls:

  • Influence. This determines what percentage of the particles is affected.

  • Multiplier. This determines how much of the velocity is inherited from the emitter. A multiplier of 0 implies no inheritance, and 1.0 passes 100% of the emitter velocity to the particles.

Bubble Motion

Bubble Motion includes another set of parameters that are common to the Super Particles class of particle systems. These parameters are used to impart a wobbling motion to particles. Unfortunately, they aren't particularly intuitive and often require good viewport feedback to properly visualize. There are three main parameters to control Bubble Motion:

  • Amplitude. This parameter controls the distance at which the particle will wobble away from its original direction.

  • Period. This parameter controls the cycle time of particle oscillation, which is similar to waveform frequency.

  • Phase. This parameter is used here similarly as it was with rotation, controlling the initial wobble offset.

Particle Spawn

All Super Particles have common controls for particle spawning. Particle spawning is the emission of particles from particles. There are several methods by which particles can be spawned over time:

  • None. This method causes zero particle spawning.

  • Die after Collision. This method causes particles to die when they collide with a Deflector space warp.

  • Spawn on Collision. This method performs the opposite of the previous method, causing particles to be born on collision.

  • Spawn on Death. This method causes a sort of fireworks effect by creating particle spawns when a particle dies.

  • Spawn Trails. This method is pretty self-explanatory, causing particles to spawn trails of new particles behind them over their lifetime.

Each of the spawning controls has common parameters used to control the events and the spawned particles:

  • Spawns. This parameter determines the number of particle spawns that happen over a particle's lifetime.

  • Affects. This parameter determines the percentage of particles that will produce spawning.

  • Multiplier. This parameter is a value that multiplies the number of particles spawned at a given event.

  • Directional Chaos. This parameter is used to vary the direction at which particles are spawned.

  • Speed Chaos. This parameter is similar to Directional Chaos, but instead varies the speed at which particles are spawned on a frame-by-frame basis.

  • Scale Chaos. This parameter is similar to Directional Chaos and Speed Chaos, but varies the scale of spawned particles.

  • Lifespan Queue. This parameter is used to determine several alternate lifetimes for spawned particles. Values are created and stored in the queue and then passed on to spawned particles on an event-by-event basis.

  • Object Mutation Queue. This parameter works with instanced geometry and causes spawn particles to switch between instanced geometry types referenced in the queue on an event-by-event basis.

Parameters Unique Among Super Particles

As mentioned earlier, the main differences between the Super Particles are the methods used to emit particles. These unique features are described in the following sections.

Blizzard

Blizzard includes the following values:

  • Width and Length. These are used to determine the size of the rectangular emitter object.

  • SuperSpray

    SuperSpray includes the following values:

    • Off Axis and Spread. These are two related values that control the angle of emission from a single point in space. Off Axis determines the angle off axis from Z (straight up through the emitter), similar to the elevation of a gun in a turret. Spread controls the angle at which particle emission is varied in a fan direction.

    • Off Plane and Spread. These are two more related values to control the angle of emission from a point. Off Plane controls the angle of emission rotated around the plane of the emitter, similar to the azimuth of a gun in a turret. Spread controls the conical spread angle along the axis of emission. A value of 180 creates a complete cone shape.

    PArray

    PArray is unique because it uses geometry for emitters and can explode that geometry into fragments to use as particle geometry:

  • Object-Based Emitter. This is a pickbutton used to determine which object will be used for emission.

  • There are several particle formation methods:

    • Over Entire Surface. This method creates particles evenly over the surface of the emitter geometry. This is the most commonly useful method and thereby the default.

    • Along Visible Edges. This method snaps particle emission to the visible edges of the emitter object.

    • At All Vertices. This method restricts emission to the vertices of the emitter object.

    • At Distinct Points. This method isolates particle emission to a given set of distinct points on the emitter's surface.

    • At Face Centers. This method emits particles from the centers of all faces on the emitter object.

    • Use Selected Sub-Object. This method is a check box that applies to all the previous methods. This enables the user to further restrict emission to only the selected sub-objects (faces, edges, verts) of the emitter geometry.

    PArray has some unique parameters and methods for creating object fragments for particle geometry:

  • Thickness. This parameter determines the size of the fragments' extrusion.

  • The following three methods determine how an object will fragment:

    • All Faces. This method forces each face of the emitter geometry to be used as a polygonal fragment.

    • Number of Chunks. This method sets a minimum number of fragments created.

    • Smoothing Angle. This method controls the number of fragments created based on the angle of the surface normals of the emitter object. The higher the angle, the fewer the fragments created.

    PCloud

    PCloud is unique because it emits particles from within a volume instead of a surface. There are four methods to define the volume:

    • Box Emitter. This method is a variable box shape controlled by length, width, and height.

    • Sphere Emitter. This method is a variable spherical shape.

    • Cylinder Emitter. This method is a variable cylindrical shape with parameters similar to Box Emitter.

    • Object-Based Emitter. This method uses selected geometry from the scene to use as a volume emitter.

    PCloud has unique particle motion methods:

    • Random Direction. This method emits particles along random vectors.

    • Enter Vector. This method uses X,Y, and Z vectors to determine the exact emission direction.

    • Reference Object. This method uses a scene object's Z-axis as the target direction for particle emission.

    • + Share This
    • 🔖 Save To Your Account

    Peachpit Promotional Mailings & Special Offers

    I would like to receive exclusive offers and hear about products from Peachpit and its family of brands. I can unsubscribe at any time.

    Overview


    Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Peachpit products and services that can be purchased through this site.

    This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

    Collection and Use of Information


    To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

    Questions and Inquiries

    For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

    Online Store

    For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

    Surveys

    Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

    Contests and Drawings

    Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

    Newsletters

    If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email ask@peachpit.com.

    Service Announcements

    On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

    Customer Service

    We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

    Other Collection and Use of Information


    Application and System Logs

    Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

    Web Analytics

    Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

    Cookies and Related Technologies

    This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

    Do Not Track

    This site currently does not respond to Do Not Track signals.

    Security


    Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

    Children


    This site is not directed to children under the age of 13.

    Marketing


    Pearson may send or direct marketing communications to users, provided that

    • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
    • Such marketing is consistent with applicable law and Pearson's legal obligations.
    • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
    • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

    Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

    Correcting/Updating Personal Information


    If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

    Choice/Opt-out


    Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.peachpit.com/u.aspx.

    Sale of Personal Information


    Pearson does not rent or sell personal information in exchange for any payment of money.

    While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

    Supplemental Privacy Statement for California Residents


    California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

    Sharing and Disclosure


    Pearson may disclose personal information, as follows:

    • As required by law.
    • With the consent of the individual (or their parent, if the individual is a minor)
    • In response to a subpoena, court order or legal process, to the extent permitted or required by law
    • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
    • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
    • To investigate or address actual or suspected fraud or other illegal activities
    • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
    • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
    • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

    Links


    This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

    Requests and Contact


    Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

    Changes to this Privacy Notice


    We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

    Last Update: November 17, 2020