Unreal Engine plugin · Documentation

Unreal Engine 5.4 to 5.8
C++ runtime
Windows

Fulmen.
Lightning explosions.

One actor, twenty electric explosions. Drop it, pick a preset: a bolt falls from the sky, the ground cracks, sparks fly, the air bends around the blast and real lights hit your set. Every layer can be tuned or switched off.

Quick start
20 presets
13 layers
Distortion
Scorch styles
Sequencer
Blueprints
All settings
Compatibility
Support

Quick start

Drop BP_FulmenEnable the plugin, then drag BP_Fulmen from Plugins > Fulmen Content > Blueprints onto the ground.

Pick a presetIn the Details panel, open the Preset menu. It applies at once.

Watch itTurn on Realtime in the viewport (Ctrl+R): it repeats every few seconds. Or press Play.

The Details panel of a Fulmen Explosion: Preset menu, Size, Intensity, Seed, Asymmetry, the Detonate and Add Explosion At Playhead buttons, and the 13 layers — The Details panel: the Preset menu, global settings, trigger buttons and the 13 layers.

The Fulmen sample level: a dark grid hall with numbered booths, a lightning strike hitting one of them — The sample level `/Fulmen/Maps/Fulmen_Showcase`: 21 booths, every preset and the 5 scorch styles. Walk in and press Play.

20 presets

The numbers are the booths of the sample level. Each loop plays the preset as it ships, with nothing changed.

13 layers

An explosion is made of layers. Each one has an Enabled box and its own settings, so you can build your own explosion from any preset. Here is Strike Large with one layer switched on at a time:

Two more layers do not show in a still: Charge (arcs converge on a growing core before the blast, used by Plasma Pop, Overload and Nova) and Shake (camera shake for the players nearby, in game).

Distortion

The blast bends the image behind it, like hot air. A heat bubble works as a lens with a heat-haze shimmer, a shock ring runs over the ground and up the walls, and red and blue split apart. Drag the handle:

Strike Large with distortion: the grid bends around the blast

Distortion offDistortion on

No sprite: there is never a square edge around the effect.
What is in front of the blast stays sharp. Only what is behind it bends.
Settings: Bubble Radius, Bubble Strength, Shimmer, Ring Radius, Ring Strength, Ring Width, Ring On Surfaces (3D shell or a ring facing the camera), RGB Split, Punch (a short chromatic kick at the flash).

Scorch styles

The burn mark left on the ground is a decal with relief that catches the light. Its cracks glow, then cool down from the edge towards the centre. Pick a look in Scorch > Style:

Sequencer and Movie Render Queue

Sequencer with the playhead on frame 18: the viewport shows the explosion at that exact moment — The explosion follows the Sequencer playhead. Scrub back and forth: every frame is exact.

Scrub to a frameWith Follow Sequencer ticked (the default), Fulmen reads the time of the open sequence.

Add Explosion At PlayheadSelect the actor and click the button: the blast lands on that frame. Click again on other frames for more.

RenderMovie Render Queue gives the same frames every time, sub-samples included. Nothing to key.

For full manual control, tick Use Custom Time and key Custom Time. Time Scale below 1 gives slow motion.

Blueprints

Spawn an explosion anywhere during gameplay, and react when it hits:

Spawn Fulmen ExplosionFulmen

Exec

Preset Strike Large

Location

Rotation

Size 1.0

Life Span 0 = auto

Return Value

On Hit (BP_Fulmen)Event, fired in game for every hit

Location

Size

DetonateTarget is Fulmen Explosion

Exec

Spawn Fulmen Explosion: the explosion blows at once (after its leader or charge) and the actor removes itself when it is over. Rotation sets the surface: its up axis is the normal, so a wall hit is a rotated actor.
On Hit: use it for damage, sounds or gameplay. Patterns (Chain, Barrage...) fire it for each hit.
Detonate, Get Fulmen Time, Is Explosion Active, Get Explosion Duration.
Make your own child Blueprints of BP_Fulmen with your settings, like a reusable "my lightning grenade".

All settings

Fulmen (main)

Preset	One of the 20 presets. Changing it sets every layer.
Placement	Ground: arcs crawl on the ground, sparks bounce on it, a scorch mark stays. Air: the blast goes all around, sparks and debris fall to the floor below.
Size	Scales the whole explosion (sizes, distances, speeds). 1 suits a human-size scene.
Intensity	Global brightness of filaments, flash, lights and distortion.
Seed	Another explosion with the same settings.
Asymmetry	Tilts each blast to a random side, so no two look the same.

Trigger and Pattern

Repeat	An explosion every `Interval` seconds from `First Explosion` (`Count` 0 = forever).
Times	At the exact times of the `Times` list.
On Fire	Only when Detonate is called.
Pattern	Single, Chain (along X), Barrage (random in a disc), Ring, Cluster (in a volume). `Hits`, `Spacing`, `Delay`, `Size Jitter`, `Height`.

Layers

Strike	Height, Lean, Bolts (several converging), Leader Time, Decay, Restrikes, Restrike Window, Brightness, Width, Shape.
Burst	Count, Length, Spread (90 = hemisphere, 180 = all around), Grow Time, Duration, Retarget Rate, Bend, Hit Surfaces, Shape.
Ground Arcs	Count, Length, Crawl Time, Duration, Follow Ground, Lift, Linger (crackles that keep popping), Linger Arcs, Linger Length, Shape.
Charge	Time, Arcs, Radius, Brightness, Core Size, Implode.
Flash	Star (Size, Duration, Brightness, Rays, Chroma), Beams, lens streak, glow ball, Pre Flash.
Ring	Radius, Duration, Width, Brightness, Ease, Arcs along the front.
Sparks	Count, Speed, Spread, Gravity, Drag, Bounce, Lifetime, Streak Time, Min and Max Streak, Fade In, colours, Embers.
Debris	Count, Speed, Spread, Size, Gravity, Bounce, Lifetime, Heat, colours.
Smoke	Puffs, Spread, Size, Rise, Lifetime, Opacity, Color, Flash Lit.
Scorch	Style, Relief, Radius, Lifetime, Glow Time, Opacity, Glow Brightness, Glow Color.
Distortion	See Distortion.
Light	Intensity (candelas), Color, Radius, Lift, Shadows, Afterglow, Bolt Light.
Shake	Strength, Radius, Duration, Frequency, In Sequences.

Look, Motion, Sound, Time

Look	Core, Glow and Haze colours, Core Width, Glow Width, Haze Width, brightness of each, Min Pixel Width, Hot Spots, Dim Tint. Filaments are never thinner than a pixel: thinner ones get dimmer, so they never shimmer.
Motion	Shape Rate, Swim Rate, Smoothness, Flicker, Flicker Rate, Branch Rate, Branch Flicker.
Sound	A sound played at every hit in game, and its volume. No sound ships with the plugin.
Time	Follow Sequencer, Use Custom Time, Custom Time, Time Scale, Time Offset.

Filaments, flash and smoke keep the same brightness at any exposure, so a preset looks the same in every level. The lights are physical: tune Light > Intensity to your exposure.

Compatibility and performance

Unreal Engine 5.4, 5.5, 5.6, 5.7 and 5.8, Windows. Runtime module: works in packaged games.
Everything is drawn by one custom primitive per explosion, rebuilt each frame only while the explosion is visible. The distortion is one post-process pass per explosion, only during its first half second.
A large preset draws a few thousand filament points and a few hundred sparks.
The filaments are translucent additive: they do not appear in Lumen reflections, but their lights do.
Not network replicated: explosions are cosmetic. Call Detonate or Spawn Fulmen Explosion from your own replicated gameplay.

Support

Questions and bug reports: contentcreatorassetspack@gmail.com. Tell us your engine version and, if you can, attach a screenshot of the actor's settings.

Fulmen.Lightning explosions.