texture mapping different objects in three.js - three.js

We are studying on product designer project. Designer is ready.
I want to do 3d preview result with three.js.
How can we texture one side of phone case? or can we border texture mapping?
OBJLoader version:
http://www.shopilife.com/baskiburada/viewer/viewer_4.html
And some obj files cannot be textured. Error is "GL_INVALID_OPERATION : glDrawElements: attempt to access out of range vertices in attribute 2"
http://www.shopilife.com/baskiburada/viewer/viewer2.html

First, regarding re-texturing the back vs. front of the phone case. The approach here is to seperate the UV coordinates on the model itself. This way you have two sets of materials/textures/UVs. Then during runtime you load them both using a MeshFaceMaterial to load the two materials in an array like so:
materialArray.push(THREE.BasicMeshMaterial({color: 0xff0000})); //use whatever Material type you'd like of course
materialArray.push(THREE.BasicMeshMaterial({color: 0x0000ff}));
var multipleMaterial = new THREE.MeshFaceMaterial(materialArray);
phoneCaseMesh= new THREE.Mesh( geometry, multipleMaterial );
Then when you want to switch one out you would grab the mesh and change the mapping to the desired side something like:
phoneCaseMesh.material.materials[1].map = THREE.ImageUtils.loadTexture( 'newtexture.jpg' );
Second, regarding the Error on you second sample, WestLangley is correct the OBJ file has no UV coordinates to map to, so the index is out of bounds when you apply a texture. If you look at both OBJ files your iphone4.obj has vt entities while the untitled.obj is just v and f. Hope that helps

Related

Three.js emissive materials don't cast shadow

Conext
I'm using three.js, #react-three/drei and #react-three/fiber.
I'm loading a GLTF file that contains emissive materials using
const gltf = useLoader(GLTFLoader, '/model.glb')
When I inspect the loaded data like this:
for (const key of Object.keys(gltf.materials)) {
const v = gltf.materials[key] as MeshStandardMaterial & Material
if (!v.isMeshStandardMaterial) return
console.log(key, v, v.emissive, v.emissiveIntensity, v.emissiveMap)
}
I can see that certain materials have a color set and their emissiveIntensity is equal to 1.
Problem
Objects made of these emissive materials load and display correctly on the scene. They have the desired color. There is, however, one problem. I would like those emissive materials to behave like a directonalLight/pointLight - i.e. cast shadows and cause reflections. Right now, they only display as shiny blobs, but their light doesn't affect other objects.
Question
How do I make emissive materials cast shadows and create reflections? Do I need a shader or is there some hidden option that I'm not seeing?

Changing parents of a 3D model while keeping the same position

I'm using three.js library to work with 3d models (mostly .glb but it shouldn't matter)
The idea is to import a 3d model that contains groups and meshes. I want to be able to move meshes between already existing groups within a model without changing the visual representation of the model.
Piece of my code is below. movedInternal is
movedMesh.matrixWorldNeedsUpdate = true; // not sure if it's needed
let meshPosition = new THREE.Vector3();
movedMesh.getWorldPosition(meshPosition);
oldParent.remove(movedMesh);
newParent.add(movedMesh);
movedMesh.worldToLocal(meshPosition);
movedMesh.position.set(meshPosition.x, meshPosition.y, meshPosition.z);
And this is not working. Mesh changes its global position because new parent’s position is not the same as previous parent position, but I expect it to stay where it was but change its local position considering new parent’s position.
What do I do wrong?
I think you need to update the movedMesh's world matrix after you change its parents. When you .remove() then .add(), it doesn't know that its parents have been updated (Three.js usually does it when you're rendering, but this is happening before the next frame render).
let meshPosition = new THREE.Vector3();
movedMesh.getWorldPosition(meshPosition);
oldParent.remove(movedMesh);
newParent.add(movedMesh);
// Here it needs to re-learn its new coordinates
movedMesh.updateMatrixWorld(true);
movedMesh.worldToLocal(meshPosition);
movedMesh.position.set(meshPosition.x, meshPosition.y, meshPosition.z);
I've been searching for this solution since a week and haven't been able to tackle the exact problem. Though my question is diferent but has same scenario, I would like to give a solution for those, looking for it.
I have a 3D object with different child meshes, and i want to replace one of my child mesh with another 3D model.
Below code snippet:
replacementMesh is a new 3D object, meshToReplace is the child mesh that needs to be replaced.
// Copy the transformation matrix from obj1 to obj2
replacementMesh.matrix.copy(meshToReplace.matrix);
// Update obj2's position, rotation, and scale to match the transformation matrix
replacementMesh.position.setFromMatrixPosition(replacementMesh.matrix);
replacementMesh.rotation.setFromRotationMatrix(replacementMesh.matrix);
replacementMesh.scale.setFromMatrixScale(replacementMesh.matrix);
meshToReplace.parent.add(replacementMesh);
meshToReplace.parent.remove(meshToReplace);

I can't get the aoMap showing in three.js using a glb/gltf asset

I’m having a hard time getting an aoMap working in three.js…
I have a glb asset with an aoMap on the red channel or something. When I bring it into to the babylon viewer, I can see the ao just fine, but it wont show up in the three.js viewer or my project. I think this has something to do with a second set of uvs, but I can't find a resource that involves doing that on top of using the gltf loader… I really don't know what to do here. Any response would be greatly appreciated!
Here is my code (I’m using a html-canvas as the texture)
And I get the model’s geometry and diffuse texture (all white) as desired, but the aomap isnt showing…
code
babylon viewer
three.js viewer
working application with shadows included in diffuse
not working, diffuse is just white, and aoMap is not showing
You're right about needing a second set of UVs. The reason behind this is that diffuse textures often repeat (think of a brick wall, or checkered t-shirt). AO shading, however, is more likely to be unique on each part of the geometry, so it's almost never repetitive. Since this often would need an alternative UV mapping method, the default is to use a second set of UVs.
You could do 2 things:
Re-export your GLTF asset with a duplicate set of UVs.
Duplicate existing UVs in Three.js by creating a new BufferAttribute in your geometry:
// Get existing `uv` data array
const uv1Array = mesh.geometry.getAttribute("uv").array;
// Use this array to create new attribute named `uv2`
mesh.geometry.setAttribute( 'uv2', new THREE.BufferAttribute( uv1Array, 2 ) );
.getAttribute and .setAttribute are methods of BufferGeometry, if you want to read more about them.

Texture looks like one flat color, lacking detail of image, in three js

I am attempting to modify the ThreeJS materials example seen here, and have been fairly successful so far in reverse engineering it in to my own minimalist demo.
The problem comes when I attempt to modify the materials.
I have changed mlib["Orange metal"] to the following:
"Orange metal": new THREE.MeshLambertMaterial( {
map: carTexture,
envMap: skyBox,
combine: THREE.MultiplyOperation
} )
carTexture is a reference to the following:
var carTexture = THREE.ImageUtils.loadTexture('texture/blue.jpg');
carTexture.wrapS = carTexture.wrapT = THREE.RepeatWrapping;
carTexture.repeat.set(3,3 );
carTexture.wrapS = THREE.RepeatWrapping;
carTexture.wrapT = THREE.RepeatWrapping;
And while this has changed my final output, the detail in the texture is missing.
For reference: here is the texture file:
Which clearly has a metalic flake texture.
Meanwhile my final product looks like this:
Completely smooth.
Yet, if I add a taurus with the exact same texture, I can see the details quite clearly:
I have played around with the dimensions of the texture file (up to several thousand percent), and the reflectivity of the MeshLambertMaterial, but not been able to see any change at all.
Your model needs UV coordinates.
On a model like this, it will need to be done in 3d software such as 3ds Max, Maya etc.
If you could get your hands on a version of the model which already has the correct UV coordinates set it would save you all the hassle.
Setting up UV coordinates is not so easy on a model like this if you have never done it before.
An alternative may be generate your paint flake in your shader (without using UV) rather than in a texture (I willl soon be attempting this myself for a personal project).
HERE are some youtube videos on UV unwrapping in 3ds Max

exporting a scene from blender to threejs: every object has just one single material

I have made a small scene in blender (6 objects, each using 1 to 4 materials).
When exporting this (using the materials, and the scene option) with the dev exporter and loading it via:
var loader = new THREE.ObjectLoader();
loader.load( 'assets/scene.json', function ( scene ) { ...
And then checking the scene, I can see it has 6 children (good) and that each of the five children only has one MeshLambertMaterial (instead of the material mix from blender) bad.
Any hints on what I am doing wrong?
Those are btw basic materials (just a color basically) no textures or anything.
The scene renders correctly (minus the material mix).
Here is a link to the 113kb scene file (zipped): http://jppresents.net/static/blender/exportBug/scene.zip
Looking at the file I think all materials are there - so the problem must be the way I load it?
Not a solution, but a work around:
Since the only difference between all my materials was just the color, I have now applied exactly one material with a multi colored texture per object.
Then I uv-mapped the faces of the object to the colors corresponding to the previously set material color.
This was easy using the hotkey "shift + G" which lets you select all faces with the same material. (Then just assign them to the texture material, move/scale those in the uv-view to the part of the texture that matches the old color.)

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