3d unit object size

[basarab]

Hi!
How can I get 3d object size in cocos units?
I tried using getComponent(Collider).worldBounds.halfExtents but propably its not what I’m looking for
any other solutions?

[linrm]

What do you need 3d object size for?

[basarab]

I have to move, rotate and scale my 3d object to fit 2d UI transform. But as you can see at the screen it doesn’t fit well. In this iteration I’m using collider boundingSphere radius to get size (i don’t care much about what side of my 3d object is larger than others)

I use this code:

import { Camera, Collider, Component, Input, input, Node, Quat, RigidBody, UITransform, Vec3, view, _decorator } from 'cc';
const { ccclass, property } = _decorator;

@ccclass('NewComponent')
export class NewComponent extends Component {

    @property(Node)
    object3D: Node

    @property(Node)
    objectUI: Node

    @property(Camera)
    camera: Camera

    start() {
        input.on(Input.EventType.TOUCH_END, this.move, this)
    }

    move() {
        this.object3D.getComponent(Collider).enabled = false
        this.object3D.getComponent(RigidBody).enabled = false

        // finding rotation
        const newObjectRotation = new Quat()
        Quat.fromEuler(newObjectRotation, 0, 0, 0)

        // finding position
        let scaleX = view.getScaleX()
        let scaleY = view.getScaleY()

        const localPosX = this.objectUI.worldPosition.x * scaleX;
        const localPosY = this.objectUI.worldPosition.y * scaleY;

        const newLocal_2 = new Vec3(localPosX, localPosY, 0.5);

        const newObjectPos = this.camera.screenToWorld(newLocal_2);

        // finding scale
        const screenHeightInUnits = this.camera.orthoHeight * 2;
        const screenWidthInUnits = screenHeightInUnits * view.getVisibleSize().width / view.getVisibleSize().height

        const xPixelsInUnit = view.getVisibleSize().width / screenWidthInUnits
        const yPixelsInUnit = view.getVisibleSize().height / screenHeightInUnits

        const contentSize = this.objectUI.getComponent(UITransform).contentSize;

        const radius = this.object3D.getComponent(Collider).boundingSphere.radius

        let newObjectScale: Vec3
        let multiplier: number = 1

        const yContentSizeInUnits = contentSize.y / yPixelsInUnit
        const xContentSizeInUnits = contentSize.x / xPixelsInUnit

        // you need to fit a circle on the smaller side of the sprite
        if (yContentSizeInUnits <= xContentSizeInUnits) {
            multiplier = yContentSizeInUnits / (radius * 2)
        } else {
            multiplier = xContentSizeInUnits / (radius * 2)
        }

        newObjectScale = new Vec3(this.object3D.worldScale).multiplyScalar(multiplier)

        this.object3D.worldPosition = newObjectPos
        this.object3D.worldScale = newObjectScale
        this.object3D.worldRotation = newObjectRotation
    }
}

Before moving:

After moving:

[basarab]

Btw I can use collider world bound by using:

        const objectUnitSize = new Vec3(this.object3D.getComponent(Collider).worldBounds.halfExtents).multiplyScalar(2)

        let newObjectScale: Vec3
        let multiplier: number = 1

        const yContentSizeInUnits = contentSize.y / yPixelsInUnit
        const xContentSizeInUnits = contentSize.x / xPixelsInUnit

        // you need to fit a circle on the smaller side of the sprite
        if (yContentSizeInUnits <= xContentSizeInUnits) {
            multiplier = yContentSizeInUnits / objectUnitSize.y
        } else {
            multiplier = xContentSizeInUnits / objectUnitSize.x
        }

Somehow it’s ended up the same way as using radius

[basarab]

I’m going to share my project with code in case you may need this to test by yourself
NewProject_2.zip (1.6 MB)

[basarab]

Hi again
I made some tweeks to make the problem more realistic for my case

            const halfSize = this.object3D.getComponent(Collider).worldBounds.halfExtents.multiplyScalar(2)

            let newObjectScale: Vec3
            let multiplier: number = 1

            const yContentSizeInUnits = contentSize.y / yPixelsInUnit
            const xContentSizeInUnits = contentSize.x / xPixelsInUnit

            // you need to fit a circle on the smaller side of the sprite
            if (yContentSizeInUnits <= xContentSizeInUnits) {
                multiplier = yContentSizeInUnits / (halfSize.y * 2)
            } else {
                multiplier = xContentSizeInUnits / (halfSize.x * 2)
            }

            newObjectScale = new Vec3(this.object3D.worldScale).multiplyScalar(multiplier)

It works fine with one object:

Working

But won’t work with other:

Not working

I guess the problem is with scaling of my object but anyway I can’t get the result I want
NewProject_2.zip (2.3 MB)