5. Scaling Props

Sometimes during platformers, you’ll encounter obstacles that change their dimensions. These could be platforms that grow and shrink in size, or get taller or shorter along a certain axis. When an object’s dimensions are modified this way, it’s called modifying its scale.

An object's scale tells you how much to multiply each of its dimensions, relative to itself. Normally, objects have a scale of {X := 1.0, Y := 1.0, Z := 1.0}. If you double the Z value of an object’s scale, it becomes twice as tall. If you half it, half as tall.

Scale is the final part of the transform puzzle. In this section, you’ll learn how to manipulate scale to create objects that grow and shrink to different sizes.

Making Props that Scale

Follow these steps to build the code that scales your props:

1. Create a new Verse class named scaling_prop that inherits from movable_prop using Verse Explorer. Add the <concrete> specifier to this class to expose its properties to UEFN.

   Verse

        # A prop that scales toward either a given scale or a Creative prop's scale.
        scaling_prop<public> := class<concrete>(movable_prop):

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2. Add the using { /Fortnite.com/Devices/CreativeAnimation } and using { /UnrealEngine.com/Temporary/SpatialMath } statements to the top of the file to import these modules. You’ll need these to animate your prop. The tooltips used in this section are also included here.

   Verse

        using { /Fortnite.com/Devices }
        using { /Fortnite.com/Devices/CreativeAnimation }
        using { /Verse.org/Simulation }
        using { /UnrealEngine.com/Temporary/SpatialMath }
   
        MatchScaleTargetTip<localizes>:message = "The optional position to move to World Space. Use this if you do not want to set a MoveTarget."
   
        # A prop that scales toward either a given scale or a Creative prop's scale.
        scaling_prop<public> := class<concrete>(movable_prop):

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3. At the top of the scaling_prop class definition, add the following fields.

   1. An editable vector3 array ScaleTargets. These are the scales that your prop will grow and shrink to. After Move() completes, the prop’s scale will be multiplied by this value.

      Verse

       # The array of vector3 targets for the RootProp to scale to.
       @editable {ToolTip := MoveTargetsTip}
       var ScaleTargets:[]vector3= array{}
      

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   2. An editable optional creative_prop named MatchScaleTarget. If you want your prop to scale to match another prop’s scale, you can set this value rather than using the ScaleTargets. For example, you could use this if you wanted to create a series of platforms that all grew to the same size before resetting.

      Verse

       # The optional Creative prop for the RootProp to match scale to.
       @editable {ToolTip := MatchScaleTargetTip}
       var MatchScaleTarget:?creative_prop = false
      

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   3. A variable rotation named TargetScale. This is the scale the prop is currently scaling toward.

      Verse

       # The scale the prop is currently targeting.
       var TargetScale:vector3 = vector3{}
      

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4. Your final class definition should look like this:

   Verse

        using { /Fortnite.com/Devices }
        using { /Fortnite.com/Devices/CreativeAnimation }
        using { /Verse.org/Simulation }
        using { /UnrealEngine.com/Temporary/SpatialMath }
   
        MatchScaleTargetTip<localizes>:message = "The optional position to move to World Space. Use this if you do not want to set a MoveTarget."
   
        # A prop that scales towards either a given scale or a creative prop's scale.
        scaling_prop<public> := class<concrete>(movable_prop):
   
   
   Expand code Copy full snippet(20 lines long)

5. Since you already set up the Move() function that moves your prop in movable_prop, you can override it in this class. Override the Move() function in your scaling_prop class. In Move(), first, check if the MatchScaleTarget is set and save it in a variable ScaleToMatch. If so, set the TargetScale to the ScaleToMatch, then call MoveToEase(), passing in the TargetScale, the MoveDuration, the MoveEaseType, and animation_mode.OneShot. This is the MoveToEase() function you overloaded earlier that only modifies the scale.

   Verse

        # Scale the RootProp toward the ScaleTarget, or MatchScaleTarget if one is set.
        Move<override>()<suspends>:void=
            # Set the TargetScale to the MatchScaleTarget if it is set.
            if:
                ScaleToMatch := MatchScaleTarget?.GetTransform().Scale
            then:
                set TargetScale = ScaleToMatch
   
                # Call MoveToEase to start scaling the prop. The OneShot animation mode will play the animation once.
                RootProp.MoveToEase(MoveDuration, TargetScale, MoveEaseType, animation_mode.OneShot)

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6. If you didn’t set a MatchScaleTarget, then you need to iterate through your ScaleTargets array. In a for expression, iterate through each ScaleTarget in ScaleTargets and set the TargetScale to the ScaleTarget. Then call MoveToEase(), passing the same values as before. Your complete Move() function should look like this:

   Verse

        # Scale the RootProp toward the ScaleTarget, or MatchScaleTarget if one is set.
        Move<override>()<suspends>:void=
   
            # Set the TargetScale to the MatchScaleTarget if it is set.
            if:
                ScaleToMatch := MatchScaleTarget?.GetTransform().Scale
            then:
                set TargetScale = ScaleToMatch
   
                # Call MoveToEase to start scaling the prop. The OneShot animation mode will play the animation once.
   
   Expand code Copy full snippet(20 lines long)

7. In your prop_animator device class, add a new editable array of scaling_prop named ScalingProps. Add another for expression to OnBegin() that loops through all the scaling props and calls Setup() on them. Your updated prop_animator class should look like this:

   Verse

        using { /Fortnite.com/Devices }
        using { /Verse.org/Simulation }
        using { /UnrealEngine.com/Temporary/Diagnostics }
   
        TranslatingPropsTip<localizes>:message = "The props that translate (move) using animation."
        RotatingPropsTip<localizes>:message = "The props that rotate using animation."
        ScalingPropsTip<localizes>:message = "The props that scale using animation."
   
        # Coordinates moving props through animation by calling each prop's Setup() method.
        prop_animator := class(creative_device):
   
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8. Save your code and compile it.

Linking Props to Devices

Back in the editor, delete some of the props after the rotating props section but before the raised blocks to create another gap. Add a FG01 Punch Glove to your level. Name the glove ScalingGlove. Position the glove in the middle of the gap, and rotate it so that it’s facing up.

Setup of the punching glove. The glove scales up to create an elevator to raise players.

Select your prop animator in the Outliner, and add an array element to ScalingProps for your glove. Assign the prop with the following values:

Push your changes, then check out your props! Try varying the different scales to get different dimensions, and try scaling other props to create different scenarios!

Next Up

In the next section, you’ll combine movement, rotation, and scale to create props that can do all three!

• 

  6. Combining Movement, Rotation, and Scale

  Time to combine different aspects of your moving props with Verse to build a Fall Guys obstacle course.

Complete Code

Here is the complete code built in this section:

scaling_prop.verse

using { /Fortnite.com/Devices }
using { /Fortnite.com/Devices/CreativeAnimation }
using { /Verse.org/Simulation }
using { /UnrealEngine.com/Temporary/SpatialMath }

MatchScaleTargetTip<localizes>:message = "The optional position to move to World Space. Use this if you do not want to set a MoveTarget."

# A prop that scales towards either a given scale or a creative prop's scale.
scaling_prop<public> := class<concrete>(movable_prop):

prop_animator.verse

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }
using { /UnrealEngine.com/Temporary/Diagnostics }

TranslatingPropsTip<localizes>:message = "The props that translate (move) using animation."
RotatingPropsTip<localizes>:message = "The props that rotate using animation."
ScalingPropsTip<localizes>:message = "The props that scale using animation."

# Coordinates moving props through animation by calling each prop's Setup() method.
prop_animator := class(creative_device):