Mesh Balloons

Spawning a Static Mesh instead of a camera-facing sprite can increase the realism of the effects you are creating. In the following tutorial, we will show how to set up a Niagara Emitter to spawn Static Meshes instead of sprites.

Prerequisite Step: This tutorial uses an imported balloon mesh. You can find free meshes online by doing a simple search. Otherwise, you can practice by using the Shape_Sphere static mesh, which is found with the Starter Content. If you have not done so already, make sure that you have added your own mesh for the balloon to this project, or add the Starter Content to your project.

Create a Material

The effect in this guide is meant to look like a cloud of balloons being released. To enhance this effect, you will make a simple material that makes the mesh look like a rubber balloon.

1. Right-click in the Content Browser and under Create Basic Asset select Material.

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2. Name the new Material Balloon_Material. Double-click it to open in the Material Editor.

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3. In the Palette panel, type Particle in the search bar. Select Particle Color and drag it into the Graph to add a Particle Color node.

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4. Drag off the RGB output and connect the wire to the Base Color input on the Material node.

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5. While holding down the 1 key, click in the Graph. This creates a Constant node. Copy and paste it twice, for a total of three Constant nodes.

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6. Connect the output on one Constant node to the Metallic input on the Material node.

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7. You can set the Value of a selected constant in the Details panel, under Material Expression Constant. This material is not metallic, so leave the Metallic constant's value at 0.

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8. Connect the output on the second Constant node to the Specular input on the Material node.

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9. With the Specular constant node selected, set the Specular Value in the Details panel to 0.7. This will give the material a slightly reflective surface.

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10. Connect the output on the third Constant node to the Roughness input on the Material node.

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11. With the Roughness constant node selected, set the Roughness Value in the Details panel to 0.2. This will create a mostly smooth surface.

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Your final result for the Material should look like the image below.

Create the System and Emitter

Niagara emitters and systems are independent. The current recommended workflow is to create a system from existing emitters or emitter templates.

1. First, create a Niagara System by right-clicking in the Content Drawer and selecting FX > Niagara System. The Niagara Emitter wizard displays.

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2. Select New system from selected emitters. Then click Next.

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3. Under Templates, select Fountain.

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4. Click the Plus sign (+) icon to add the emitter to the list of emitters to add to the system. Then click Finish.

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5. Name the new system Balloon_System. Double-click to open it in the Niagara Editor.

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6. The emitter instance in your new system has the default name of Fountain, but you can rename it. Click the name of the emitter instance in the System Overview, and the field will become editable. Name the emitter Balloons.

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7. Drag your MeshSystem into your Level.

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   When you make a particle effect, it is always a good idea to drag your system into a Level. This gives you a chance to see every change and edit in context. Any changes you make to the system automatically propagate to the instance of the system in your level.

Change the Renderer

The Render group is last in the stack, but you need to change some things so that the effect displays the way it is supposed to. In this case, the template contains a Sprite Renderer, and this effect needs a Mesh Renderer.

1. In the System Overview, click Render to open it in the Selection panel.

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2. To make a mesh particle effect you need a Mesh Renderer module, but the template has a Sprite Renderer module. Click the Trashcan icon to delete the Sprite Renderer.

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3. Click the Plus sign (+) icon for Render and select Mesh Renderer.

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4. Click the dropdown for Particle Mesh and select your mesh. If you imported your own balloon model, select that. Or to test, you can select Shape_Sphere from the sample material.

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5. Your mesh may be too small or too big to show up well in your level. If needed, adjust the size here. Your mesh may have a default material applied to it. By enabling Override Materials, you can use the custom material you created instead. Click to enable Override Materials, then click the Plus sign (+) icon to add an element to the array.

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6. Click the dropdown for Explicit Mat, and select the material you created earlier, Balloon_Material.

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Edit Emitter Update Group Settings

First, you will edit the modules in the Emitter Update group. These are behaviors that apply to the emitter, and that update each frame.

1. In the System Overview, click the Emitter Update group to open it in the Selection panel.

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2. Expand the Emitter State module. Because you used the Fountain template, the Life Cycle Mode is set to Self. Click the dropdown and set the Life Cycle Mode to System. This enables your system to calculate the lifecycle settings, which usually optimizes performance.

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3. The Spawn Rate module creates a continuous stream of particles while the emitter is active. This module is already present in the Fountain template. Set the Spawn Rate to 100.

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Edit Particle Spawn Group Settings

Next, you will edit the modules in the Particle Spawn group. These are behaviors that apply to particles when they first spawn.

1. In the System Overview, click the Particle Spawn group to open it in the Selection panel.

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2. Expand the Initialize Particle module. This module collects several related parameters together in one module, minimizing clutter in your stack. Under Point Attributes, locate the Lifetime parameter. This parameter determines how long particles will display before they disappear. For Lifetime Mode, select Random. Set the Minimum and Maximum values to the following.

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   Setting	Value
   Minimum	2.0
   Maximum	4.0

3. Locate the Color parameter. You can choose to have all your balloons be one solid color, or use one of the other modes to add some variety. In this example, you can set the Color Mode to Random Range. This will create your balloons in random colors that fall in a range between two set colors. Change the RGB values until you achieve the look you like. The colors you set here are applied to the material you created earlier. In this example, the colors are set to red and blue.

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   Setting	Color Minimum	Color Maximum
   Red	1.0	0.0
   Green	0.0	0.0
   Blue	0.0	1.0

4. Under Sprite Attributes, set Sprite Size Mode, Sprite Rotation Mode, and Sprite UV Mode to Unset. Since you are using a mesh, these attributes are not needed for this effect.

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5. When you first set your mesh, you may have resized it at that time. But you may want some variation in the size, so some balloons are larger than others. Under Mesh Attributes, set Mesh Scale Mode to Random Uniform. Set the Mesh Uniform Scale Min to 0.7 and Mesh Uniform Scale Max to 1.0. If you used a sphere instead of a balloon mesh, you may want to set the Mesh Scale Mode to Random Non-Uniform to give some irregularity to the shape of your spheres.

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6. The Add Velocity in Cone module is not needed for the effect you are making. You don't want the balloons to spread out in a cone shape. Click on the trash can to remove this module from your stack.

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7. The Add Velocity module will give the particles movement as soon as they spawn. Add the Add Velocity module to the Particle Spawn section by clicking the Plus sign (+) icon and selecting Add Velocity.

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8. Because this effect is meant to look like balloons being released, some randomness to the speed of the particles is needed. Click the downward arrow next to the Velocity value fields, and select Random Range Vector. This adds minimum and maximum velocity fields so that each balloon can be assigned a velocity value from within this range, adding randomness.

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9. Set the Velocity Minimum and Maximum values to the following. This gives the effect a small amount of movement on the X and Y axes, and a larger amount of movement on the Z axis.

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   Setting	Value
   Minimum	X: 15, Y: 25, Z: 50
   Maximum	X: 30, Y: 30, Z: 100

10. The Sphere Location module module controls the shape of the location where sprites spawn. You can have the sprites spawn in a sphere shape, and you can set the size of the sphere shape by indicating a radius. Set the Sphere Radius to 200. This spreads the particles out more, as balloons would do when released.

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Edit Particle Update Group Settings

Now you will edit the modules in the Particle Update group. These behaviors apply to an emitter's particles and update each frame.

1. In the System Overview, click the Particle Update group to open it in the Selection panel.

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2. Typically, you would use the Gravity Force module to simulate how gravity affects objects. You can also use it more generally to add acceleration to your particles. Set the Gravity Force X, Y and Z values to the following.

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   Setting	Value
   X	10
   Y	10
   Z	40

3. The Drag module applies drag to the particles, which slows them down. Set the Drag to 1.0.

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4. The Scale Color module is part of the Fountain template, but this effect does not require it. Click the Trash can icon to remove the Scale Color module.

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End Result

Congratulations! You've made a mesh particle effect in Niagara. You learned how to create a material, apply the particle color to that material, and use a static mesh as your particles. Continue to explore the options in the modules to refine the effect.