Particle Emitters 2

[Vinz]

Credits: @Hermit for Filter Mode research; @tillinghast for animated Gravity error; @GhostWolf for Time & Sort Primitives Far Z definitions, and PE2 Alpha Key functionality; @doom_sheep for Squirt-Visibility interaction

This SD Magos'-centric thread attempts to document Particle Emitters 2.
Orientation axes are Warcraft 3's.
X - Forward
Y - Rightward
Z - Upward

Velocity = Distance covered; influenced by speed, variation, and gravity

Required: A pre-1.29 copy of the game containing the old MPQs that Magos' Editor can navigate.

* = Not observable in Magos', and will have to be tested in-game.

VISIBILITY Toggle: 0 turns off emission, while values over 0 turn it on.

EMISSION RATE The amount of particles generated per second. The interval between emissions is capped at ~0.05s (?). Going past this threshold will emit those excess particles in bulk. Emission rates below 1 will only create particles if the sequence is longer than 1 second. Visibility and Emission Rate react differently to animation, and so are useful for different situations. For sequences during which they're blank; similar to Geoset & Material Alpha Animations, Visibility toggles on, while Emission Rate results in 0. For convenience - if you want an emitter turned OFF for a minority of animations, animate Visibility. If you want an emitter turned ON for a minority of animations, animate Emission Rate.

SPEED By default, causes the particle to move towards its Z. This direction can be changed through emitter or parent rotation. Animated changes in speed will only affect newly emitted particles; thus gravity is the only way to accelerate.

VARIATION The percentage of randomness with which the particle can deviate from its base speed. 1 means speed can go down to zero, or double; and 2 means it can go -1x negative*, or triple. High variation can lead to bottleneck emission when used with Latitude.

LATITUDE Angles to which the particles will fly, deviating from the emitter's facing direction. A value of 90 means the particles will go towards a semi-spherical area, while 180 removes angular restrictions. 90 Latitude 180 Latitude

WIDTH - Along the X Axis (frontward/backward) LENGTH - Along the Y Axis (left/right) Width and Length determine the rectangular field in which particles are spawned. Magos' Editor displays these properly with MDXs, but not so with MDLs, where they are reversed. 100 Width; 10 Length 100 Length; 10 Width

GRAVITY An accelerating force that points downwards in the absence of Model Space rotations. Negative values will make the particles go up. Magos' will not save animated Gravity in MDX; only in MDL. Nor will it open any MDX with animated Gravity.

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Flags

UNSHADED* - Will be unaffected by the game's lights. Generally always on for effects. The 'sun' comes from the south west by default.

UNFOGGED* - Will not be tinted nor shrouded by terrain fog.

LINE EMITTER* - Whether or not the particles will fly towards two axes instead of three. By default, checking this means the particles will fly YZ. With Latitude, the angles will expand sideways. Example usage in Thunder Clap, where it's used with an emitter rotation to make the particles fly XY. Rotation: { 0, -0.707107, 0, 0.707107 }

SORT PRIMITIVES FAR Z* - Renders the furthest particles on top.

MODEL SPACE* - Whether or not the particle moves and rotates with its parent nodes and the model. Model Space sees extensive use in Radiance.

XY QUAD - Whether or not the particle will be rendered as a flat, one-sided plane facing the Z axis. For consistent rendering, XY emitters require both Latitude and Velocity at 1 or higher; they might not be visible otherwise. XY Quads will rotate to XY angles within Latitude.* With Model Space, they will change facing according to the node's rotation.* XY Quads see extensive use in Void Disc.

SQUIRT* - Creates all the particles indicated by the Emission Rate at the first keyframe available per animation, instead of over time. If the opening frame of the animation is not set to 0, it will ignore your frame settings and squirt when the animation begins. Visibility animation may be used for sequence-wide settings, but Squirt cannot be timed properly with that alone. Use Emission Rate for this purpose. Used by War Stomp and Thunder Clap.

HEAD- The default. When rendering an emitter without Head nor Tail settings, the game will consider it a Head emitter. Leaving the Head box unchecked will hide the particles in Magos' only. TAIL* - Whether or not the particle will be followed by a tail facing its flying direction. Tails consider the texture's left as their front. In MDL, mdlvis saves the head setting properly, while changing tails to heads. If both are checked, it saves them both properly. If neither are checked, it checks heads. In MDX, mdlvis saves both settings properly. Tail emitters see extensive use in Piercing Thrust.

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Segments

Each particle from this emitter will fade through the three colors, sizes, and visibilities (alphas), with each segment's duration decided by <Time>. Particles will not scale with the models they're attached to, even if they're Model Space. Scale will still affect emitters' spawn field and velocity.

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Misc

SPRITES ROWS & COLUMNS - Used to indicate what's displayed for sprite textures, starting from the upper left. Textures\Sparkle_Anim.blp ReplaceableTextures\Weather\Clouds8x8.blp 4x4 sprite; 4 rows & 4 columns 8x8 sprite Layout for a 4x4 texture HEAD (Life Span & Decay) - Animates sprite textures for head particles, starting from 0. "Life Span" refers to the transition between Segments 1 and 2; while "Decay" refers to that between 2 and 3. REPEAT - How many times the component repeats its run during the particle's lifetime. Inputting 0 in all fields will only display the first image in the sprite. Set this way, ReplaceableTextures\Weather\Clouds8x8.blp will fade through its first and last cell throughout the particle's life.

LIFE SPAN - Time before the particle disappears and expires.

TAIL LENGTH* - Segment size only determines width for tails. This is the length; influenced by velocity.

PRIORITY PLANE* - Used to layer/manually determine which particles are displayed on top of each other. Unlike its Material counterpart, Magos' will not save this field in MDL; only in MDX. Adding it to an MDL through other means will make the model unopenable in Magos'. Like its Material counterpart, mdlvis will erase its data.

REPLACEABLE ID* - Inputting the following values will replace the TextureID: 1 - Team Color 2 - Team Glow 11 - Cliff 31 - Lordaeron Tree 32 - Ashenvale Tree 33 - Barrens Tree 34 - Northrend Tree 35 - Mushroom Tree 36 - Sunken Ruins Tree 37 - Outland Tree Example usage in the Wisp, which uses Team Glow tails. Magos' will not save this field in MDL; only in MDX. Adding it to an MDL through other means will make the model unopenable in Magos'.

TIME - The decimal percentage of the lifespan that serves as a midpoint for particle transition. Ideally above 0.00 and below 1.00. The lower the particle Time, the shorter it takes to transition between Segments 1 & 2; while increasing transition time for Segments 2 & 3.

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Filter Modes

Filter Mode Behaviour Can be used in material layers Can be used in particle emitters Opacity (Alpha) Draw order Depth set Sort order errors with its own geoset None (aka Opaque) The geoset draws as solid, with no blend to the frame buffer. Yes No Fixed Opaque queue On No Transparent (aka 2 Color Alpha) The geoset draws as solid except for regions over which the texture map alpha channel is black, where the geoset is completely transparent. The cutoff from transparent to solid is 75% white in the alpha channel. Yes No Fixed or animated Opaque queue On No Blend Standard filter mode using an 8-bit alpha channel texture and/or opacity channel. New pixel color and the current frame buffer pixel color are blended together using the new pixel alpha value as a blending factor. Yes Yes Fixed or animated Transparent queue Off Yes Additive The geoset adds its RGB color values to the frame buffer (saturating at pure white), causing a ghost-like glowing effect. Most spells use this to make glowing effects. Yes Yes Fixed or animated Transparent queue Off No AddAlpha Behaves the same as Additive, but cannot be used in particle emitters. Yes No Fixed or animated Transparent queue Off No Modulate Pixels' color values are multiplied together; The geoset multiplies its RGB values to the frame buffer, making a semi-transparent darkening of the background. Yes Yes Fixed Transparent queue Off No Modulate2x The geoset first doubles its initial RGB values, then multiplies them against the frame buffer. This technique causes both brightening and darkening in one pass. Yes Yes Fixed Transparent queue Off No AlphaKey (aka 2 Bit Alpha) Behaves the same as Transparent, but cannot be used in material layers. No Yes Fixed or animated Transparent queue Off Some filter modes that can be selected from the drop-down list in particle emitters cannot actually be used for particles; they only work in material layers. Alpha Key was mistakenly designed by Magos as a particle emitter flag, even though it is actually a filter mode for particles; as a result, the flag is lost after saving MDX files; it remains when MDL files are saved, but the checkmark will not be visible when the model is reopened. Modulate2x filter mode cannot be chosen anywhere and has to be added by editing the MDL file with a text editor, e.g. Notepad. MDL files with this filter mode cannot be opened by War3 Model Editor, while MDX files can be opened, but Modulate2x is converted to None after saving. MDLX Converter can convert models that use Modulate2x in material layers, but only Retera's Matrix Eater and Model Studio can open and convert models with particle emitters that use this filter mode. Blend removes the transparent parts. It is a staple of blood spurts, dark glows, and black smoke. Additive removes the black parts, and lightens the texture. It 'adds' to what's in the background. The darker/the more colored an additive particle becomes, the weaker it is. Additive is a staple of light glows. Modulate removes the white parts, and is used for GenericGlowModX.blp, among others. Cannot fade. Blends are incompatible with other particles for the most part, and will flicker through each other in-game, if not in the Model Editor as well. This can be circumvented through the use of Priority Planes. Flare.blp is a comparatively smooth and versatile light, and can be used with Blend in addition to Additive, as opposed to other glows. Some textures with alpha channels can be used with Blend, while certain black ones are fitted for Modulate. Most of the rest are only viable with Additive. What is listed as "Add Alpha" in Magos' Particle Emitters is actually Alpha Key, where alphas below 0.75 are invisible. Changing an emitter's filter mode to AddAlpha will cause the entire model to display as a green checkered cube in-game.

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Tips

• Black and white colors are useful to prevent your effect from looking monotone, whatever your primary hue is. Use darker particles as cushions below the other particles, or colder colors as outliers, and lighter, warmer ones for the centers. For segment colors, it's recommended to go from light to dark as particles fade.
• Use color variation to your advantage. Fade an emitter to a nearby color over its lifetime.
• It is oftentimes better not to have constant particle size. For sparks, consider having their scaling at 0 for the third segment, while retaining high alpha. On the inverse, dust clouds look better when they fade to 0 alpha in bigger sizes.
• Glows, glows, glows. Use them to give your effect atmosphere. Use smooth glows such as flare.blp for generic light, and thicker ones such as LavaLump2.blp for sparks. Some of the default colored glows are weaker and unsuitable for sparks, so consider using custom ones when necessary.

Things to Know

• Individual particles cannot rotate independently, apart from tails forced to turn by gravity.
• Using MDL/X Converter will remove Billboard settings for Particle Emitter nodes.

In-Game Discrepancies

• Gravity and Speed are calculated differently
• Particles and their movement are rendered smoother in-game; even moreso in the World Editor

Testing in-game/in-editor often is integral to effects, and modeling at large. Back up often. Good luck, have fun!

 

[Veritas 117]

This is incredibly useful. Understanding what each of those fields actually means is really helpful when it comes to making and manipulating existing particles.

nice job on this.

 

[Retera]

For any further reading I also recommend reading the code that powers open source rendering of WC3 particle emitters in replica technologies (below is written by Ghostwolf):

flowtsohg/mdx-m3-viewer

I've been working with a desktop game port of the code above on the LibGDX engine and it looks very War3-alike:

To me, it really shows how hard this guy worked researching not just how to edit the format, but exhaustively how to display it in a technical sense.

 

[Jaccouille]

An update on current tutorial is much appreciated, I don't really understand the effect of the XY Quad even by reading the description you provided, most likely because I am not used with this context, haven't toyed enough with particle emitter, maybe add an example, e.g "This is usually checked for projectile effect".

 

[Vinz]

An update on current tutorial is much appreciated, I don't really understand the effect of the XY Quad even by reading the description you provided, most likely because I am not used with this context, haven't toyed enough with particle emitter, maybe add an example, e.g "This is usually checked for projectile effect".

Edited the description and added an example.

 

[Kyrbi0]

This is fantastic. I don't know how we went so many years as a community without attempting to codify & understand such an integral part of an integral part of the community's tool-base.

The only thing this needs now, in my mind, is a copious amount of pictures (providing examples, both with in-game/standard SFX & perhaps a single "dummy SFX" that showcases each change), and a test map with a bunch of custom 'dummy SFX' to showcase stuff as well.

 

[Hermit]

Good job; it's about time someone made this.

You might want to explain the Rows and Columns (that are used when the particles are using sections of the texture at a time) and update the list of replaceable textures since it is incomplete; Replaceable ID 36 is used by sunken ruins trees (Doodads\Terrain\RuinsTree) and Replaceable ID 37 is used by outland mushroom trees (Doodads\Terrain\OutlandMushroomTree).

I suggest going a bit more into detail about filter modes; at least mention all of them that can be used in particle emitters.

Filter Modes

Filter Mode	Behaviour	Can be used in material layers	Can be used in particle emitters	Opacity (Alpha)	Draw order	Depth set	Sort order errors with its own geoset
None (aka Opaque)	The geoset draws as solid, with no blend to the frame buffer.	Yes	No	Fixed	Opaque queue	On	No
Transparent (aka 2 Color Alpha)	The geoset draws as solid except for regions over which the texture map alpha channel is black, where the geoset is completely transparent. The cutoff from transparent to solid is 75% white in the alpha channel.	Yes	No	Fixed or animated	Opaque queue	On	No
Blend	Standard filter mode using an 8-bit alpha channel texture and/or opacity channel. New pixel color and the current frame buffer pixel color are blended together using the new pixel alpha value as a blending factor.	Yes	Yes	Fixed or animated	Transparent queue	Off	Yes
Additive	The geoset adds its RGB color values to the frame buffer (saturating at pure white), causing a ghost-like glowing effect. Most spells use this to make glowing effects.	Yes	Yes	Fixed or animated	Transparent queue	Off	No
AddAlpha	Behaves the same as Additive, but cannot be used in particle emitters.	Yes	No	Fixed or animated	Transparent queue	Off	No
Modulate	Pixels' color values are multiplied together; The geoset multiplies its RGB values to the frame buffer, making a semi-transparent darkening of the background.	Yes	Yes	Fixed	Transparent queue	Off	No
Modulate2x	The geoset first doubles its initial RGB values, then multiplies them against the frame buffer. This technique causes both brightening and darkening in one pass.	Yes	Yes	Fixed	Transparent queue	Off	No
AlphaKey (aka 2 Bit Alpha)	Behaves the same as Transparent, but cannot be used in material layers.	No	Yes	Fixed or animated	Transparent queue	Off

Some filter modes that can be selected from the drop-down list in particle emitters cannot actually be used for particles; they only work in material layers.

Alpha Key was mistakenly designed by Magos as a particle emitter flag, even though it is actually a filter mode for particles; as a result, the flag is lost after saving MDX files; it remains when MDL files are saved, but the checkmark will not be visible when the model is reopened.

Modulate2x filter mode cannot be chosen anywhere and has to be added by editing the MDL file with a text editor, e.g. Notepad. MDL files with this filter mode cannot be opened by War3 Model Editor, while MDX files can be opened, but Modulate2x is converted to None after saving.

MDLX Converter can convert models that use Modulate2x in material layers, but only Retera's Matrix Eater and Model Studio can open and convert models with particle emitters that use this filter mode.

 

[Vinz]

@Hermit this is great! Quoting it in the main post. Thanks for the input.

 

[Kyrbi0]

Lovin' the pics.

Just a minor note: very good of you to credit & link back to Hermit's contribution, but may I suggest not doing the whole "giant quote" thing? Not only does it mess with the formatting a bit (tries to squeeze that whole table into a Quote block), but it italicizes everything which is weird.

Instead, you can just quote it directly (BBCode & text & such), with a bit at the top crediting Hermit (hyperlinked to his comment).

 

[Retera]

Priority Plane* - Used to layer/manually determine which particles are displayed on top of each other.

Unlike its Material counterpart, Magos' will not save this field in MDL; only in MDX. Adding it to an MDL through other means will make the model unopenable in Magos'.

Like its Material counterpart, mdlvis will erase its data.

if you know this, just go and fix them, okay??? it's our civic duty

Edit: or do you want us to suffer?

 

[maddeem]

Finally particle emitters make sense, thank you!

 

[tillinghast]

What's with animated gravity? Magos reverts it to static after i reload the model, if i add it through mdl text editing then it gives an error. Looks like RMS can handle it without problems and yet sanity checker gives a yellow warning about it. I guess it's better to just create a copy of emitter with different static gravity?

 

[Bleeq]

There seems to be a minimum combination of Emissionrate(ER) and LifeSpan(LS) in-game. When I had a tail emitter with ER 6, and LS 0.15, I would get emissions, but dropping ER to 5 simply broke it and I got nothing.

With LS 0.8, I could drop ER down to 2 or 3. Some other options like speed and tail length did vary though, too.

 

[Retera]

Magos reverts it to static after i reload the model

It's probably broken. Knowing that certain parts of the model are lost when opening and saving in Magos is one of the reasons that I stopped using Magos more than a dozen years ago.

Edit:

With LS 0.8, I could drop ER down to 2 or 3. Some other options like speed and tail length did vary though, too.

Which game version was this on? Did you check if your particle detail was set to Low, Medium, or High?

 

[Bleeq]

Which game version was this on? Did you check if your particle detail was set to Low, Medium, or High?

I assume it's whatever the latest version is, given I play it through the Blizzard launcher, and they've blocked me before from even testing my maps without updating -_-.

No Idea about the detail, I didn't know that was a thing. That sounds possible, though. If I discover that was the problem I'll post back.

 

[Retera]

I didn't know that was a thing.

It may have been removed on 1.32+, so it's possible that on your version the particle detail level is always maximum. It was a 2002 feature for supporting lower end hardware. Maybe the World Editor would still have a setting for it.

 

[OVOgenez]

From my observations:

• EmissionRate can be negative, which will direct the particles in the opposite direction. This can be useful to avoid rotating the emitter by 180 degrees.
• TailLength can be negative, which will make the tail appear in front of the particle instead of behind it.