The Realtime VFX Dictionary

This thread should be used to unify our language! Let’s work together to define what certain common features should be called.
In later posts I have started to collect discussions from the RealTime VFX group on facebook so they don’t get lost. I’ve tried to copy the factual parts and leave the “Thanks!” and reposts. I will work on the formatting of these posts going forward to make them more readable. If anyone wants their name removed, let me know and I’ll sort it out.

I’ll start with some suggestions:

Alpha Erosion
Description: Scaling the the levels of the alpha texture to give the appearence of the alpha eroding, or being eaten away.
Other names: Black Point Fade, Alpha Dissolve, Alpha Min/Max Scale.

Bent sprite
Description: A method of improving the lighting on a sprite. By either bending the normals, t
Other names: Benticle

Billboard
Description:A billboard is similar to a sprite but it’s not simulated and is usually constrained to only rotate around the up axis.
Other names: VAP (ViewAlignedPoly)

Camera Parented Effects
Description: A particle system that has been parented under the camera so it follows along with the player.
Other names: Camera proximity Effects, Screen attached effects

Depth Fading Particles
Description: The particles pixelshader performs a depthtest against the scene and fades the alpha accordingly. This gives the particle a soft look when intersecting with objects.
Other names: Soft particles, Z-Feathered particles, Depthtest particles.

Distance Culling
Description: A way to stop the particles from simulating/rendering after a specified distance.
Other names: Cullradius

Distance Fade
Description: A way of fading the alpha of particles based on their distance from the camera. This could be used to stop particles from clipping the screen.
Other names:

Emitter
Description: The source of particles. In most engines this is what contains all the data that determines how the particles simulate. What data is present at this level varies. Some engines have all of the settings here. Some engines have an effect container above this with additional settings. The effect container usually allows you to combine several emitters to create the effect. Example: An effect container would contain a fire emitter, a smoke emitter and a spark emitter. The spark emitter would contain data like, texture, colour, initial velocity and so on.
Other names:

Flipbook
Description: A sequence of textures compiled to one image. The pixelshader on the sprite moves the UVs to the different sections of the image and thus displaying different frames of the sequence.
Other names: Animated Texture Atlas, Spritesheet, SubUV Texture.
Common Naming Convention:
texname_atlas = Non related frames used for random texture selection.
texname_anim = An animation that has a start and end.
texname_loop = An animation that repeats indefinitely.

Force
Description: A force affects the velocity of a particle after it’s been born. This can be used to simulate wind, turbulence and attraction.
Other names: Attractor (Basic version of force)

Mesh Particle
Description: A polygonal mesh instanced onto the particles.
Other names: Entity particles

On Screen Effects
Description: An effect that plays on the players screen. This could be particle or shader driven. An example would be blood splatter on the camera.
Other names: Camera space effects, Fullscreen effects

Particlesystem
Description: A collection of emitters making up an effect.
Other names: Effect Container

Particle trail
Description: A particle rendering method where a quad strip is constructed from
the particle data.
Other names: Trail, Geotrail, Ribbon, Swoosh, Billboardchain

Preroll
Description: A method of running a particle system for a set amount of time “behind the scenes” so when it’s first made visible, it’s already in place.
Other names: Prewarm

Sprite
Description: The most basic tool of a vfx artist. In it’s simplest form it’s a camerafacing quad with a texture applied to it. There are countless variations to this with different alignment options but then one could argue that it’s a quad rather than a sprite.
Other names:

UV Distortion
Description: A method of distorting the UV coordinates to extra generate detail in an effect. Can be extended to be driven by a Motion Vector mask to blend smoothly between frames.
Other names: UV Warping

Particle trail
Description: A particle rendering method where a quad strip is constructed from
the particle data.
Other names: Ribbon.

Awesome Reference Collection by Denis Girard:

http://6packofc4.tumblr.com/ (Explosions)
http://heatdistortion.tumblr.com/ (Fire)
http://shadesofsmoke.tumblr.com/ (Smoke)
http://watersip.tumblr.com/ (Liquids)
http://billionvolts.tumblr.com/ (Electricity)
http://scifivfx.tumblr.com/ (Sci-Fi)

[QUOTE=Zoltan;20244]Particle trail
Description: A particle rendering method where a quad strip is constructed from
the particle data.
Other names: Ribbon.[/QUOTE]

The technical name for this is Billboardchain

Hello guys,

I recently posted this on the VFX Facebook group and wanted to ask the same here…had to wait on verification.

I am currently creating slides about VFX to help programming students understand what ask and look for, for VFXs in their games.

Now I can, and have, come up with my own definition for VFX and have also gotten some nice feedback on the Facebook group.

What is the definition of a VFX?

I figured the “Realtime VFX Dictionary” would be one of the best places to look.

Again, I am mainly just look for feedback and ideas on what this definition could be, as there is no “real” one out there.
From the feedback I have gotten and hope to get still, I plan on at least trying to combine many of the good definitions into one broad one.

Thanks for any input on this.

My (realtime biased) take on this:

“A special effect is any animated, at least partially procedural visual element.”

That would cover:

  • UI related stuff like the mana sphere in Diablo3 or Bejeweled’s particle rich menus.
  • Environment effects: rain, flickering displays, caustics…
  • Feedback on game actions, for example muzzle flash, hit effects and so on.

Excluded:

  • Rendering tricks like reflection, dispersion, SSS, GI.
  • Pre-animated skeletal cloth, hair, etc.
  • Any pre-rendered material used as is.

However there are still gray areas like procedural character animation, static
post process effects or basic UI animation like sliding or fading.

Impressive collection of reference footage for effects: http://ref-fx.com/