Lightning Fast

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Description

Lightning Fast is a powerful combination of materials and blueprints that implements a wide range of realistic and stylized electricity effects.

Lightning effects have plenty of uses in games, from background ambiance during a storm, and electric fences to devastating lightning guns and spells. This system is designed in mind to achieve all those effects with high performance, and AAA quality at the same time.

[DEMO]

Supported effects:

• lightning flashes
• lightning bolts
• lightning chains
• lightning strikes
• lightning discharges
• lightning beams
• lightning trails
• lightning guns
• lightning electrocute

Features:

• GPU-friendly and optimized for all platforms
• Wide range of high-quality effects
• Two types o beam rendering (spline mesh/spline billboard mesh)
• Integrated with UE4 dynamic lights and material light functions and splines
• Over a hundred parameters in materials to customize the final effect
• Spline spline-based shape of the bolt easy to adjust to the scene
• Character electrocute discharges effect
• Advanced lightning mesh editor tools
• Multiple animated lines rendered in a single beam
• Depth fade/direction fade effect
• Glow and line color
• Refraction based distortion
• Procedural beam texture
• Dynamic branch masking and fading effect

Additional content:

• prototype pack – textures and materials created for demonstration purposes
• mesh generator – an advanced tool prepared for editing and generating lightning meshes, allows implementing external lightning propagation class
• demo example map – a showcase of 14 use cases
• Procedural mesh lib – Additional library of functions that helps to create static meshes in UE4

Gallery

Documentation

Getting started

Everything starts from the geometry (meshes) and effect (materials) rendered using geometry.

The Lightning Fast mesh combined with the material has some useful features and properties that are very important in production.

• can be used with spline meshes
• can be skinned and used as skeletal mesh 
• can be scaled and keeps the proper shape
• can be used in a particle system
• can be watched from every angle

That gives us a wide range of effects that the system can handle so the package is divided into multiple blueprints specialized in custom effects.

All of the effects can be found in the Blueprint folder and are presented on ExmapleMap (Demo/Maps/LightningFastMap)

Example use-case:

1. Find folder Blueprints/LightningBolt 
2. Drag end drop BP_LightningBolt on scene
3. The effect is ready to use. Now you can adjust parameters to get the effect that you need.

Blueprints

Blueprints folder contains multiple lightning effects that show how the system works with materials and meshes is should be treated as example content or templates prepared for general use cases. Some of the effects contain blueprints the others are represented only by particle effects that the main character is using.

Check the Demo/Mannequin/ThirdPersonCharacter blueprint to analyze the implementation of the skills.

The list of effects will be extended in future updates. 

It’s good practice to create your own effects by inheriting Blueprint classes and copy material instances to your project folder.

Lightning Spline

The Blueprints/BP_LightningSpline blueprint is a simple combination of mesh spline effects and lights. You can combine any mesh created using the Lightning Fast package with splines even bending the lightning bolts is allowed. 

Drag and drop BP_LightningSpline on the scene and modify parameters. [Editing splines]

Lightning Bolt

BP_LightningBolt is a complex example of lightning bolt effect implementation based on a lightning spline blueprint. The biggest advantage of this blueprint is that can be easily integrated with every weather system.

Use the parameter World to register the blueprint in BP_LightningWorld. The BP_LightningWorld actor is the manager that changes directional light intensity and skylight intensity during stormy weather according to all managed lightning bolts.

To activate Lightning Bolt by hand (from events) use Activation function and set ActivationLoops = 0.

Lightning Beam

Dynamically updated chain of splines that connects target points in the closest range.

Simple use case of working with a beam:

1. Drag and drop BP_LightningBeam on the scene
2. Drag and drop a few target actors (BP_lightningTarget) on the scene near the lightning beam actor.
3. Select BP_LightningBeam and edit parameters:
   IsActivated=true
4. Find the InitChain array and add one element. Set up the starting chain element. 
   Set TargetActor to self it will make the beam actor the source of effect.
   
5. Play and watch how the beam connects the target actors that are moving around.

The concept of the BP_LightningBeam actor is based on the idea that the chain should be represented by multiple nodes connected by spline meshes in a specific order. The list of nodes and order can be set by the user or generated automatically. 

The BP_LightningBeam effect is divided into the static and dynamic parts.

• Static (set by user) – predefined, represented by InitChain structure created by the user during activation.
• Dynamic (generated) – generated starting from the last element of the static fragment using an algorithm of searching in range.

InitChain is the array that describes the connections between chain elements. The first element of the array is a root (starting point).  For example, the Init Chain of lightning guns can be represented by 2 nodes. The first node is the gun muzzle and the second one is the hit point. The ParentIndex is the index of the parent node in the InitChain.

You can even specify a looping shape in init chain by this kind of config:
InitChain[0] = (TargetActor=Target0, ParentIndex=0) //start, points to self so it’s empty
InitChain[1] = (TargetActor=Target1, ParentIndex=0) //spline from element 0 to Target1
InitChain[2] = (TargetActor=Target2, ParentIndex=1) //spline from element 1 to Target2
InitChain[3] = (TargetActor=Target0, ParentIndex=2) //spline from element 2 to Target0 (loop)

The last element of the InitChain is the starting point of searching. The search uses the attributes in the Search tab to specify which actor should be in the dynamic chain. 

After the InitChain is specified then there it comes to dynamic chain generation. ChainLength is the number of spline meshes that can be rendered by the BP_LightningBeam actor. The ChainLength attribute is used to calculate how many additional nodes should be generated. The number of the dynamic nodes that the algorithm will look for is ChainLength reduced by the number of renderable connections specified in the Init Chain.

Example situation (lightning gun)
ChainLength = 4
InitChain contains 2 elements, the connection between start point(muzzle) and one target point is represented by 1 spline mesh.
Finally, algorithm will look for 4-1 = 3 target points and try to render 3 additional spline meshes.

  The algorithm for searching is simple:

1. Find the closest target actor in range to the last element of the chain
2. Add the element to the chain.  
3. If CombinedChain is smaller than ChainLength then goto 1

After the searching process, all the nodes are linked together in a chain 0-1-2-3 … -n. UseClosestToChain=true option runs an additional update that changes the topology of the chain to render the shortest possible spline meshes. It looks for the closest connections between nodes.

Lightning Gun

A complex example of Lightning gun implementation based on the Lightning Beam blueprint. 

Lightning Discharges

Particle emitter that presents discharges effect.

Lightning Trail

Effect of trail attached to the actor example content was used as a ribbon behind the character during a slow-motion run.

Lightning Target 

Object targeted by lightning gun and other skills. Target also spawns an example of a discharging particle when it is attacked by a lightning beam or lightning gun.

Lightning Source

Folder contains a base class of dynamic light source components and light materials.

Material

M_LightningFast  is the heart of the package and all material subtypes derive functionalities from this advanced master material.

Creating material instance in UE4 is really simple. Click right on the material (M_LightningFast) and chose option “Create Material Instance”. After that operation the newly created material will be ready to configure and use on Lightning Fast meshes. You can do the same with all material instances created for specific cases stored in the blueprints folder which I am recommending to do first.

The material has a very high potential for setting up and creating a wide range of effects. The following list includes all available configuration options with usage recommendations. Some of the parameters can be hard to describe and understand at first but I encourage you to test it in the engine and check the results of changes. 🙂

Base, Fade

List of general basic options.

Group of parameters that helps to fade effect in some specific conditions. Close to the wall or unpleasant angle.

Branch, Masking

The lightning beam is built of four branches that can be displayed at the same time or one after one. This section covers the basic settings.

Masking is the feature implemented for randomly hiding the branches of lightning. Even static meshes can look dynamic and various thanks to masking some of the nodes during the update.

Beam, Bolt

Beam configuration focused on UV mapping transformations.

Bolt is the effect that allows animated offsetting of the beam position on the mesh.

Distortion, Line

Each beam is created of multiple light lines that are distorted by noise texture. The texture is moving so the effect looks dynamic and chaotic.

Describes basic parameters of the line that is distorted and generates glow.

Mesh editor

Lightning Fast package contains mesh editor BP_LightningMesh that allows the creation of unique lighting meshes. Drag and drop blueprint on scene Blueprints/LightningMesh/BP_LightningMesh to start creating a lightning mesh.

 Each mesh is generated from a node list (attribute Nodes array). The node list is an array that contains a graph of connections between nodes described using a special structure called BS_LightningNode. 

The package comes with additional tools that help to create unique lightning meshes in the Unreal Engine 4 editor. There are two methods of editing the Nodes array.

1. Editing by hand using Tree Editor
2. Editing using Tree Generator

Tree editor

Tree editor is the basic method of editing the node list multiple buttons increase the speed of building the new branches of lightning mesh.

Tree generator

Lightning Fast has an advanced system of mesh generators that can be used to automatize the creation of wide-range meshes. 

Working with generators is simple:

1. Add the generator to the Generator List used by the BP_LightningMesh editor.
2. Chose the class of generators LTG_Branch 
3. Click Evaluate All Generators
4. Double-click on the generator instance edit parameters and click “Evaluate All Generators” again.

BP_LightningTreeGenerator is the base lightning generator class that can be extended by other generators by overriding the Evaluate function. 

Example generators provided in version 1.0 of the package are described below:

LTG_Branch – Example generation that creates branched lightning effects.

LTG_Spline – Example generator that creates lightning based on spline shape.

Create static mesh

A generated mesh can be easily converted to static mesh and used in other blueprints and particle effects. A few steps are needed to do this:

1. Select BP_LightningMesh blueprint and find the component called ProceduralMesh
2. Find option UseDynamicMaterial and set it to false.
3. Click the button Create Static Mesh
4. Select where to save the mesh

UseDynamicMaterial = false forces system to use default not instanced material. If you will skip this step then newly created meshes will contain reference to instanced material ant wont save.

Questions & Answers