Developer Tutorial: Object Transitions and Rotations

Learn how to use transition plus rotation settings when relocating entities around your scenes

On this quick overview, we’ll take a look at transition and rotation configurations in the Decentraland SDK and exactly how they can be used with the organizations of your scenes.

It’s important to remember that within Decentraland, you specify the actual location of an entity making use of x, y, and z . coordinates. The Decentraland motor then renders the enterprise at that location. In order to move an entity in one position to another, you simply replace the x, y, and unces coordinates. The engine after that re-renders the entity in the new position.

So , for example , if a container is in one corner of the scene and you change the coordinates to the center from the scene, then the engine understands which “path” the enterprise needs to follow in order to proceed to the new position.

The same applies to rotations, in this you set the angle a good entity is facing. Should you ever change that angle, then your engine will rotate the particular entity to face the new path.

Transitions figure out the rate at which changes within a scene appear to a player. These types of transitions are often referred to simply by game developers as “lerping”. Even though the state change that will describes the new position might be instantaneous, transitions make the modifications appear smoothly.

Imagine moving a package from point A in order to point B. You do not necessarily want your container to magically teleport in order to point B. Instead, you desire it to slide throughout your scene from stage A to point B.

Let’s take a look at exactly where transition and rotation configurations are applied to entities and exactly how different timing selections effect the appearance of transitions.

Throughout this guide, we’ll use the same fundamental scene to showcase various ways in which transitions can be used. Given that transitions are only manifested whenever something changes over time, we are going to use a simple PointerUp and PointerDown event audience to trigger changes within the scene.

 transfer * as DCL through ‘metaverse-api’ 
import createElement, ScriptableScene from “decentraland-api”
 export default class Motion extends ScriptableScene  
state =
buttonState: 2
   async sceneDidMount()  
this.subscribeTo(“pointerDown”, e =>
this.setState( buttonState: 2 )
)
this.subscribeTo(“pointerUp”, e =>
this.setState( buttonState: 3 )
)
   async render()  
return (
<scene>
<cone
position= x: this.state.buttonState, y: 1, z: 3
transition=Add your transition here.
/>
</scene>
)

For reference, we will use the Entity Interface section in the documentation.

Let’s start off searching at what happens when there is simply no transition applied to a position change:

https://medium.com/media/7dab1707db25d2f3ba802a9f5f05c9b3/href

When we click, or even release our click, around the cone to trigger the particular change in position, it occurs instantly. This is exactly what we should anticipate! While the transition is jumpy, it still changes place.

Now, let us look at what happens when we include a linear transition to our cone object.

 transition=  
position:
duration: 200,
timing: “linear”

https://medium.com/media/debd16a41614b24539f90c78ed7daeca/href

Since we additional a linear transition, the particular movement between the two says happens more smoothly. Moreover, the acceleration of the item is constant throughout the 200ms runtime.

Let’s go through the transition when we change the time to quadratic-in.

https://medium.com/media/ce91d48ac0b4b6082a0edd0b842e8f88/href

Making use of different timings affects just how your transition appears. Right here, the quadratic-in timing provides some punchiness to our changeover. The acceleration of the cone has a quadratic progression.

You can see all of the changeover timings listed on the Base Entity portion of the Entity Interface web page on our documents. If you’re using a source program code editor like Visual Business Code, the editor furthermore shows you the list of feasible values as an autosuggestion. Simply place the cursor where you would add the timing worth and kind ctrl + space to reveal the list.

Let’s observe how we can use transitions intended for rotation.

Here is our updated code:

 import * as DCL from ‘metaverse-api’ 
transfer createElement, ScriptableScene from “decentraland-api”
 export default course Movement extends ScriptableScene  
state =
buttonState: 30
   async sceneDidMount()  
this.subscribeTo(“pointerDown”, e =>
this.setState( buttonState: 30 )
)
     this.subscribeTo(“pointerUp”, e =>  
this.setState( buttonState: 90 )
)
   async render()  
return (
<scene>
<cone
rotation= x: 90, y:this.state.buttonState, z:0
position= x: 2, y: 1, z: 3
transition= rotation: delay:400, duration: 200,
timing: “bounce”
/>
</scene>
)

Let’s observe what happens to our cone now.

https://medium.com/media/5a78f0ad185033df1f96370ecf29760a/href

We’ve added and transformed a few things in our program code. As you’ll notice within the video, our transition is usually delayed. You can add a postpone attribute to add a brief temporarily stop to the movement defined within your code. We also transformed the timing to bounce , which usually, like quadratic-in , adds dynamism for your transition.

Let us see what a transition can perform to a scale change, or even changing the size of an entity.

https://medium.com/media/948a731871401f9ff553d717bce47475/href

Transitions work marvels along with scaling entities up or even down. We only needed to add a few lines associated with code to achieve the effect above.

Now, let’s take a look at some different rotation configurations. Let’s start with a new picture and a new object:

 import * as DCL from ‘metaverse-api’ 
transfer createElement, ScriptableScene from “decentraland-api”
 export default course Rotation extends ScriptableScene  
state =
buttonState: 0
   async sceneDidMount()  
this.subscribeTo(“pointerDown”, e =>
this.setState( buttonState: 90 )
)
     this.subscribeTo(“pointerUp”, e =>  
this.setState( buttonState: 0 )
)
    
   async render()  
return (
<scene>
<cylinder
rotation= x: 90, y:0, z:this.state.buttonState
position= x: 5, y: 1, z: 5
transition=
rotation: duration: 200, timing:“linear”

/>
</scene>
)

We can replace the rotation of our cylinder having a simple mouse click. In this 1st example, we rotate our own cylinder around the Z axis whenever we click on the entity. Here is what happens when we run our scene:

https://medium.com/media/6e051c70349d46d6ba3096e312d34123/href

For individually revolving objects, this method is straightforward and easy.

For more difficult rotations, we can use a mother or father entity to rotate several objects at once, or to replace the axis of rotation.

Let’s make some quick changes:

 < scene> 
< enterprise
position= x: 3, y: 0, z: 3
rotation= x: 0, y:0, z:this.state.buttonState
transition= rotator: duration: 200, time: “linear”
>
< canister
position= by: 4, y: 1, unces: 4 }
/>
< /entity>
< /scene>

We’ve developed parent entity that performs the rotation instead of the person object. Let’s see what happens…

https://medium.com/media/6e22916a8f6f470a682a2a2509900800/href

If the axis associated with rotation is around the center of the particular parent entity, as our own cylinder isn’t centered in the parent, then it will appear in order to rotate following an arc.

Now that we’ve noticed rotation examples with both indie and nested entities, let us look at Decentraland’s billboard setting.

Billboard setting overrides all rotation qualities and automatically orients the particular entity to look at the user. We are able to add this feature to the cylinder or entity with:

 billboard=2 

You can find the billboard attributes on the Base Entity section of the Entity Guide page.

Therefore , now we have:

 < cylinder 
position= x: 5, con: 1, z: 5 }}
rotation= by: 90, y: 23, z .: 55 }}
billboard=2
/>

We’ve set several rotation values, but while you see in the video beneath, the values are overridden by the billboard property.

https://medium.com/media/65183cfc28c59ab6ecc996817b76d738/href

Similarly, using the lookAt home overrides all preset rotator values. lookAt is a convenient way to rotate an enterprise so that it faces a specific stage, expressed using x , y , and z coordinates. This saves you through having to perform trigonometric computations to figure out the rotation ideals you would need on every axis. With the code beneath, we can see how the property gets rid of rotation settings.

 export default class Rotator extends ScriptableScene  
state = in front
buttonState: one
  async sceneDidMount()  
this particular. subscribeTo(“pointerDown”, e => in front
this. setState( buttonState: -15 )
)
  this. subscribeTo(“pointerUp”, electronic =>  
this. setState( buttonState: fifteen )
)
  is parked , 
  async render()  
return (
< scene>
< cylinder
position= x: 5, con: 1, z: 5 }
rotation= by: 90, y: 23, unces: 55 }}
lookAt= x: 90, con: this. state. buttonState, z .: 3 }}
/>
< /scene>
)
}
}

https://medium.com/media/602e4aad35faf6c7b65d2b15fd1291f4/href

If you would like to dig a little much deeper into the transition and rotator settings for entities, make sure you refer to our docs. Most of the concepts we reviewed in this particular blog post are already covered within the Organization Reference plus Picture Content Guide .

We’re working hard to make the docs the source of reality for everything related to the particular SDK — make sure you open a pull ask for or an issue on GitHub if we are missing something that you need.

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Developer Tutorial: Object Changes and Rotations was originally published within Decentraland on Medium, where people are continuing the particular conversation by highlighting plus responding to this story.

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