[Unity] How to light up trajectory via Trail Renderer

Unityで確認

Check with Unity

Finally, you will be able to draw a trajectory like this.

I have tried lighting up the tuna trail

I think there are a few tuna jumping around like flying fish in the following piece. The white tracks coming out from behind those tuna are the “trail renders”.
(Click the arrow button at the center of the screen to start.)

In this article, I am going to show you how to use this trail renderer in STYLY.

What is Trail Renderer?

Trail may refer to “a trail” in English. It also means something like a “meteor’s tail,” and this time it might be closer to the image of the latter.

Trail Renderer allows you to create a trajectory behind an object as it moves.

It is included in Unity by default, so you don’t need to add an asset for usage.

For more information, please see the official page of Unity.
https://docs.unity3d.com/ja/2017.4/Manual/class-TrailRenderer.html

Using the Trail Renderer in Unity

Now, let’s see how to use the trail renderer.

Set up a ball

First, let’s create a Unity project and set up a sphere.

Create Emptyを選択

Select Create Empty

Click on “GameObject > Create Empty” in the menu bar.

Continue and click on “GameObject > 3D Object > Sphere”.

Sphereを選択

Select “Sphere”

Look at the “Scene” tab. I believe the sphere was placed at the origin as shown below.

球を原点に配置

Place the ball at the origin

In the “Hierarchy” tab, I believe we have added “GameObject” and “Sphere” as shown below.

Hierarchyウィンドウを確認

Check the Hierarchy window

As shown in the figure below, the Sphere should be subordinate to GameObject.

SphereをGmaeObjectに格納

Storing the Sphere in GmaeObject

It’s hard to understand if the name is still “GameObject”, so let’s change the name to “Axis” as follows.

Axisに名称変更

Name changed to Axis

Select “Sphere” again.

Sphereを選択

Select “Sphere”

When selected, go to the Inspector tab and change the Transform > Position > X to 3. It’s the “Sphere” position that changes, not the Axis’. Be mindful not to make a mistake here.

SphereのPosition xを3に

Sphere, Position x to 3

The position of the ball was slightly shifted as shown below.

球の位置がずれた

The ball was out of position

Create an animation of a ball in circular motion

Next, let’s create an animation that rotates the sphere.

Click “Window > Animation” in the menu bar.

Animationをクリック

Click on Animation

You should now see the “Animation” tab as shown below.

Animationタブを表示

View Animation Tab

In the Hierarchy tab, select Axis.

Axisを選択

Select Axis

 

Createをクリック

Click on Create

With “Axis” selected, go to the “Animation” tab and click “Create”.

Then the following dialog will be displayed.

Please save the file as “Circular.anim” in an appropriate folder.

アニメーションファイルを保存

Save the animation file

 

Animationタブ

Animation Tab

Then, the “Animation” tab will look like the following-

Click on “Add Property” and click on the + to the right of “Transform > Rotation”.

Rotation右の+ボタンをクリック

Click the + button on the right of Rotation

Then, the “Animation” tab will look like the following.

Click on “▶” to the left of “Axis:Rotation” and select “Rotation.z”.

Rotation.zを選択

Select “Rotation.z”

Change the number in the red frame to “60” and press enter. Then, the white vertical line will move to the “1:00” point.

Change the number in “Rotation.z” to “360” and press enter.

Rotation.zを360に設定

Set Rotation.z to 360

Now that you’ve made it this far, let’s run the scene!

球が回転

The ball spins

The ball moved in circular motion!

Trailing the ball with a trail renderer

Finally, it’s time for the trail renders.

First, select “Sphere”.

Sphereを選択

Select Sphere.

Click on “Component > Effects > Trail Renderer” in the menu bar.

Trail Rendererを選択

Select Trail Renderer

The “Inspector” tab now has a new component called “Trail Renderer”.

Trail Rendererの設定

Trail Renderer settings

Let’s run the scene once and for all!

ピンクの軌跡を確認

Check out the pink trail

A pink trajectory has been displayed!

Adjusting the lifetime and thickness of the locus

Let’s get the trails (trails) in shape.

First, set “Time” to “1”, as the life of the trail is set as one second.

Next, we will adjust the “Width” graph. If you double-click on the bottom right side of the graph, you’ll get one more control point, so place it exactly at the bottom right. It should look like the diagram below.

Timeを1に設定

Time is set to 1

Let’s run the scene at this point!

軌跡が徐々に細くなる

The trajectory gets progressively narrower.

The trajectory is getting progressively thinner!

Change the color of the locus

The locus is pink is because the material has not been applied. From there, we will create a material.

Right-click on the appropriate folder on the ‘Project’ tab and select ‘Create > Material’.

Materialを選択

Select Material

The material will be named as “Trail”.

Materialの名前をTrailに変更

Changed the name of Material to Trail

 

Alpha Blended Premultiplyに設定

Set to Alpha Blended Premultiply

In the Inspector tab, change Shader to Particles > Alpha Blended Premultiply.

Once the material is created, set it to “Materials > Element 0” in the “Trail Renderer” section of the “Sphere” section.

Element0をTrailに設定

Let’s run the scene!

軌跡が白になった

The trajectory turned white

The trajectory has turned white!

Changing the texture of the locus

Let’s change the texture of the locus.

In the “Inspector” tab of the “Trail” material, change “Particle Texture” to “Default-Particle” as shown in the image below.

テクスチャをDefault-Particlに変更

Changed texture to Default-Particle

Let’s run the scene again!

軌跡がより薄くなった

The trajectory became thinner

How to upload to STYLY

Once you’ve done that, you can now prefabricate Axis in the “Hierarchy” tab and upload it to STYLY.

Axisをプレハブにする

Make Axis prefab

Check out this article on how to upload a prefab from Unity.

How to upload a prefab from Unity to STYLY

Take a look at a sample scene.

The trajectory of the ball is now properly displayed!

With the Trail Renderer, you can easily add effects to moving objects. We hope you’ll try different variations!

×