Niagara Emitter and System Editor Reference

This page describes the user interface (UI) of the Niagara Emitter and System Editor.

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Overview

The Niagara Emitter Editor can be opened by double-clicking any Niagara emitter, or through the context menu by right-clicking a Niagara emitter and selecting Edit. The Niagara System Editor can be opened in the same way, by double-clicking a Niagara system or by right-clicking a Niagara system and selecting Edit.

This document identifies and describes the parts of the Niagara Emitter and System Editor. Because the UI of the editor is mostly the same for both emitters and systems, descriptions for both have been included.

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  1. Menu Bar

  2. Tool Bar

  3. Preview Panel

  4. Parameters Panel

  5. System Overview

  6. Selection Panel (the Stack)

  7. Timeline Panel

  8. Curves Panel

  9. Niagara Log Panel

Menu Bar

File

Command

Description

Save

This saves the current emitter.

Save As

This saves the current emitter under a different name.

Open Asset

This displays a window to select other assets.

Save All

This saves all assets and levels in this project.

Choose Files to Save

This displays a dialog with options for saving assets and levels.

Connect to Source Control

This displays a dialog where you can connect to source control, allowing source control functions to be performed on content.

Edit

Command

Description

Undo

Undo the last action.

Redo

Redo an action that was undone.

Undo History

Displays a dialog listing all undo actions.

Asset

Command

Description

Find in Content Browser

This switches to most recently used Content Browser, and selects the current asset in that Content Browser.

Reference Viewer

This displays a dialog that shows all of the current asset's references.

Size Map

This displays an interactive map showing the approximate size of the asset and everything it references.

Audit Assets

This opens the Asset Audit UI and displays information about the selected assets.

Window

Command

Description

Toolbar

Shows or hides the Toolbar.

Preview

Shows or hides the Preview panel.

Curves

Shows or hides the Curves panel.

Timeline

Shows or hides the Timeline panel.

System Details

Shows or hides the System Details panel.

Parameters

Shows or hides the Parameters panel.

Selection

Shows or hides the Selection panel.

Attribute Spreadsheet

Shows or hides the Attribute Spreadsheet.

Preview Scene Settings

Shows or hides the Preview Scene Settings.

Generated Code

Shows or hides the Generated Code panel.

Niagara Log

Shows or hides the Niagara Log panel.

Toolbar

Toolbar

Tool Name

Description

Save

Save Icon

This saves the current emitter.

Browse

Browse Icon

This switches to the most recent Content Browser and selects the current emitter.

Apply

Apply Icon

This pushes the compiled script to the project world.

Compile

Compile Icon

This compiles all the modules in the emitter. You can also change the Auto-Compile settings by clicking the dropdown arrow.

Thumbnail

Thumbnail Icon

This generates a thumbnail image of the Asset.

Bounds

Bounds Icon

This shows the bounds of the scene in the Preview panel. You can also access Bounds Options by clicking the dropdown arrow.

Simulation

Simulation Icon

Click this to open a dropdown list displaying Simulation Options.

Preview Panel

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Menu Item

Description

Viewport Options

Realtime

This toggles real-time rendering in the viewport. Changes you make in the emitter stack will immediately be shown in the viewport, even if the emitter is not compiled.

Show Stats

Toggles showing stats in the viewport. If Realtime is not enabled, Show Stats automatically enables it.

Show FPS

Toggles showing frames per second (FPS) in the viewport. If Realtime is not enabled, Show FPS automatically enables it. Enabling Show FPS also automatically enables Show Stats.

Viewpoint Type

Perspective

This is the default viewpoint used in the viewport.

Orthographic

You can choose Top, Bottom, Left, Right, Front or Back. Selecting one of these changes the View Mode to Wireframe.

View Mode

Lit

This is the default setting; it renders the scene with normal lighting.

Unlit

This setting renders the scene with no lights. No light maps, dynamic lights, static lights, or emissive materials affect the scene.

Wireframe

This setting renders the scene in brush wireframe. This displays the raw triangles of everything in the viewport, and turns off the back faces to make the scene more readable.

Detail Lighting

This setting renders the scene with detail lighting only. This means only lighting with normal data pulled from materials will be used. Color emitted from lights will affect the scene.

Lighting Only

This setting renders the scene with lighting only, and no textures. Only the vertex normals of the scene will be taken into account.

Reflections

This setting renders the scene with reflections only. This includes both reflection captures and Screen Space reflections.

Player Collision

This setting will render a color-coded view of what a Player or Pawn can collide with. Static mesh collision displays as green, volumes as pink, and brushes as a grayish-violet.

Visibility Collision

This setting will render a color-coded view of what Actors in the scene will block visibility traces. Static mesh collision displays as green, volumes as pink, and brushes as a grayish-violet.

Optimization Viewmodes

Light Complexity

This setting renders a view showing where raw light overlaps.

Lightmap Density

This setting renders a view of lightmap density in the scene, with blue being the least dense and red being the most dense.

Stationary Light Overlap

This setting renders a view of where stationary lights overlap.

Shader Complexity

This setting renders a view of the shader complexity in a scene. Light green is the least complex, moving to darker greens as complexity increases, and the most complex areas are in red.

Shader Complexity and Quads

This setting renders a view with both shader complexity and quad overdraw displayed.

Quad Overdraw

This setting renders a view with just quad overdraw complexity displayed.

Show

Grid

This toggles the viewport's grid.

Instruction Counts

This toggles the display of instruction counts in the upper left corner of the viewport.

Parameters Panel

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This panel lists all the emitter, particle, system, engine and user parameters that are used by the active emitter or system. From the Parameters panel, you can drag and drop parameters to the stack in the Selection panel. The number of times a parameter is referenced is shown on the right, enabling you to spot errors and make decisions on how to change your parameters. If you have other emitters open, this panel pulls in data from those open emitters. This enables the user to share data between emitters.

System Overview

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The System Overview panel gives a high-level overview of the system or emitter being edited, combining a pan-and-zoom Graph view with compact versions of the system or emitter stack. This panel is designed for easier navigating between different parts of the data, and it gives you a high level view when you open an emitter or system for the first time. You can drag-and-drop elements to and from the stack, and can even drag-copy by pressing the ALT key.

In a system, select an emitter in the Timeline panel and it will display the full stack for that emitter in the Selection panel. In this full stack view, the system information is on top, followed by the emitter module groups below. You can also get this full stack view by clicking on the emitter stack node in the System Overview panel. However, if you want a less cluttered or more focused view, you can select an individual group or module within an emitter node to display only that group or module in the Selection panel.

Selection Panel (the Stack)

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If you have a full stack view in the Selection panel, the various groups are color-coded.

  • Orange is for Emitter-level modules. Orange sections are:

    • Emitter Settings: the Emitter Properties item is in this group.

    • Emitter Spawn: what happens on the first frame.

    • Emitter Update: what happens after the first frame, as the emitter is updated.

  • Green is for Particle-level modules. Green sections are:

    • Particle Spawn: what happens when the Particle is created.

    • Particle Update: what happens during the Particle's lifetime.

    • Update Age and Solve Forces and Velocity are normally low-level, boilerplate modules that everyone uses. But these can be removed and are completely optional.

  • Red is for Renderer items. Niagara decouples simulation from rendering. This means you can create simulation behavior once, then assign multiple renderers to that simulation.

When you are editing a system, the groups, modules and items shown in the Selection panel change based on which emitter is selected in the system's Timeline panel. As described in the System Overview section, you can also select things in that panel in order to display them in the Selection panel. If you select the System node in the System Overview, you will see system-related groups which are colored Blue:

  • System Settings: this group includes the User Parameters and System Properties items.

  • System Spawn: what happens when the system is created.

  • System Update: what happens during the system's lifetime.

For more information on modules contained in the emitter stack, both default and options, see the Niagara System and Emitter Module Reference .

Timeline Panel

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With the Timeline panel, you can manage looping, loop count, bursts, random starts and stops, and spawn rate. All of these elements can interact right in the Timeline.

In a System, the Timeline panel lists all emitters active in that System, with metadata about what kind of renderers they use and the ability to toggle which emitters are active. You can control looping behavior using the Timeline, and you can set spawn burst keys in it as well. This is driven by module metadata, which can be extended by users if needed.

For more information on using Sequencer, see Sequencer Editor .

Curves Panel

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This panel provides a Curve Editor that enables the user to adjust any values that need to change during the life of a particle, or across the life of an emitter. In order for any property to be editable within the Curve Editor, that property will need to have a Distribution type that utilizes a curve, such as FloatfromCurve. For more information on working with Distributions, see the Distributions page. See the Curve Editor User Guide page for more details on using the Curve Editor.

Niagara Log Panel

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If there are any errors or other output messages, they appear here.

Other Optional Panels

There are some additional panels that are not displayed by default, but that can be opened using the Window menu. By default, these panels will display as tabs in the area where the Selection panel displays.

System Details Panel

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The System Details Panel is very similar to the standard Details panel in the UE4 Editor.

Attribute Spreadsheet Panel

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This enables you to filter and debug information coming from the CPU Simulation. For all CPU VM-based effects, you can take advantage of the attribute debugger. It allows you to see the input values going to the simulation as well as the per-particle computed values.

Preview Scene Settings Panel

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This panel contains settings for modifying the Preview panel.

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