After downloading 3D models from sketchfab.com and importing them into a Three.js scene, they are most of the times not centered and their size is very big.
Is there a way to automatically center and scale gltf models using a script or a software (working on Linux) or otherwise to do it on-the-fly in Three.js and having the camera to move around the object using OrbitControls.
Yep. This code takes a node and finds its size and centerpoint, then rescales it so the max extent is 1 and its centered at 0,0,0, and above the ground on the y axis.
var mroot = yourScene;
var bbox = new THREE.Box3().setFromObject(mroot);
var cent = bbox.getCenter(new THREE.Vector3());
var size = bbox.getSize(new THREE.Vector3());
//Rescale the object to normalized space
var maxAxis = Math.max(size.x, size.y, size.z);
mroot.scale.multiplyScalar(1.0 / maxAxis);
bbox.setFromObject(mroot);
bbox.getCenter(cent);
bbox.getSize(size);
//Reposition to 0,halfY,0
mroot.position.copy(cent).multiplyScalar(-1);
mroot.position.y-= (size.y * 0.5);
var loader = new THREE.GLTFLoader();
loader.load( 'models/yourmodel.gltf',
function ( gltf ) {
gltf.scene.traverse( function ( child ) {
if ( child.isMesh ) {
child.geometry.center(); // center here
}
});
gltf.scene.scale.set(10,10,10) // scale here
scene.add( gltf.scene );
}, (xhr) => xhr, ( err ) => console.error( e ));
To move around the object use controls.target() https://threejs.org/docs/#examples/controls/OrbitControls.target
I resized in REACT like this!
import React, { useState, useRef, useEffect } from "react";
import { GLTFLoader } from "three/examples/jsm/loaders/GLTFLoader";
const Earth = () => {
const [model, setModel] = useState();
useEffect(() => {
new GLTFLoader().load("scene.gltf", (model) => {
model.scene.scale.set(0.03, 0.03, 0.03);
setModel(model);
});
});
return model ? <primitive object={model.scene} /> : null;
};
Just call <Earth />
Other proposed solutions did not work well for me. However, I tested the simple approach below on several models to be loaded into my scenes and it works nicely.
const loader = new GLTFLoader();
loader.load("assets/model_path/scene.gltf",
(gltf) => {
gltf.scene.scale.multiplyScalar(1 / 100); // adjust scalar factor to match your scene scale
gltf.scene.position.x = 20; // once rescaled, position the model where needed
gltf.scene.position.z = -20;
scene.add(gltf.scene);
render();
},
(err) => {
console.error(err);
}
);
