I am having issues adding physics to my mesh

Questions
1

I just started using babylon js and I was trying to add physics to my 3d glb model but I get these errors
Tried to create a MeshImpostor for an object without vertices. This will fail.
It was not possible to create a physics body for this object.
I created the model in blender and exported it as a glb file
this is my code

async function add3d(path, addPhysics = false, mass = 0, friction = 0.1, restitution = 0.1) {
    return new Promise((resolve) => {
        var name = path.split("/").pop();
        var directory = path.replace(name, "");
        BABYLON.SceneLoader.ImportMesh("", directory, name, scene, (meshes) => {
            if (addPhysics) {
                meshes.forEach((mesh) => {
                    // Apply physics impostor to child meshes first
                    mesh.getChildMeshes().forEach((child) => {
                            child.setParent(null);
                        child.physicsImpostor = new BABYLON.PhysicsImpostor(child, BABYLON.PhysicsImpostor.MeshImpostor, {
                            mass: mass,
                            restitution: restitution,
                            friction: friction,
                        }, scene);
                    });
                    mesh.physicsImpostor = new BABYLON.PhysicsImpostor(mesh, BABYLON.PhysicsImpostor.MeshImpostor, {
                        mass: mass,
                        restitution: restitution,
                        friction: friction,
                    }, scene);
                });
            }
            resolve(meshes[0]);
        }, undefined, (error) => {
            console.error(`Error loading ${path}: ${error.message}`);
        });
    });
}
2

Hello, welcome!

Can you please create a PG and post it instead of your code?

Tip:

if you are inserting code here, you can format it like this:

  const isLookingNicer = true

image
image958Ă—586 31.9 KB

1 Like
3

sure!

4

nvm its working on the playground but not my actual project, even though it still gives a warning

5

is it ok if I post the link to my replit project here?

6

Do you have a git hub repo? You can post the link, sure.

7

There may be a (gltf-) root node in the meshes array. Try to skip meshes[0].

8

I’m making a racer game here’s the link:

replit.com/ @MatteoMarotta1/racer

9

Instead of assuming only the root has no vertices, I use this:

// "importedObjects" is returned by SceneLoader.ImportMesh directly or 
// ImportMeshAsync through a Promise (in which case, the following is used as the last function in the ".then" Promise chain since it doesn't return anything)

importedObjects.meshes.filter((mfilter)=>
mfilter.getVerticesDataKinds().length >0).forEach((m)=>{
   // code to process each mesh "m"
}

This is useful when doing a MergeMeshes() as well (for my purpose here, I don’t care about materials, constraints, or separate meshes):

const OneMesh = BABYLON.Mesh.MergeMeshes(m.meshes.filter((mfilter)=>mfilter.getVerticesDataKinds().length >0))
10

I believe a better approach is to have a clean model file w/o any inconsistencies.

I would also opt for explicitly adding the impostors to a predefined set of meshes:

    const addImpostor = (mesh) => {
        //
    }

    const meshesWithImpostor = [
        "sphere",
        "sphere1"
    ]

    meshesWithImpostor.forEach(meshName => {
        const mesh = scene.getMeshByName(meshName)
        mesh && (addImpostor(mesh))
    })
11

image
image1244Ă—936 26.6 KB

Changed to BoxImpostor.

(racer - Replit)

I suggest you to switch away from Replit and develop with VS Code.

https://doc.babylonjs.com/setup/frameworkPackages/es6Support

12

That works when you control the model (as in OP). My use case is importing mesh files I don’t control, then cleaning them up as best I can.

Background detail:

Just playing around creating rollable dice from obj and stl files other people created. The four samples here are “pass the pigs” and “knuckle” from Thingiverse, “mini” and “teddy” I thought were from BABYLON examples (but I can’t seem to find them now). The pink d20 “Glimmergrove” has inset numbers that are difficult to discern with the current material.

Screenshot_20240713_124105_Kiwi Browser
Screenshot_20240713_124105_Kiwi Browser718Ă—959 84.9 KB

Pass The Pigs by tmone is licensed under the Creative Commons - Attribution - Share Alike license.
Knucklebone Dice by MishaT is licensed under the Creative Commons - Attribution - Non-Commercial license.
Tales of The Glimmergrove d20 by Kazrak is licensed under the Creative Commons - Attribution - Share Alike license.
13

I got it working when I set the car imposter to a SphereImposter but I need it as a BoxImposter

14

I switched to ammo js and it works now thank you everyone

15

Have you tried usung Havok (Physics V2)?

https://doc.babylonjs.com/features/featuresDeepDive/physics/havokPlugin

“We strongly recommend using V2 over V1. A migration guide is here.”
https://doc.babylonjs.com/features/featuresDeepDive/physics/migrate

1 Like