I have 2 3D models with roughly the same (pretty much the same) dimensions; both meshes will intersect and overlap at several points. I would like one mesh to always be displayed above the other and the mesh of the object underneath is never displayed unless it isn't covered by the mesh of the object on top--much like how a vest is worn over a shirt (vest is the mesh being displayed above). Without scaling, how can I achieve this? Thanks in advance!
You need to set the renderOrder of your meshes and the depthTest property of the materials to false.
material.depthTest = false;
mesh1.renderOrder = 0;
mesh2.renderOrder = 1;
Also have a look at this jsfiddle: http://jsfiddle.net/p2nuga2f/1/
and this three.js discourse thread: https://discourse.threejs.org/t/always-render-mesh-on-top-of-another/120
Related
Coded using:
Using ThreeJS v0.130.1
Framework: Angular 12, but that's not relevant to the issue.
Testing on Chrome browser.
I am building an application that gets more than 100K points. I use these points to render a THREE.Points object on the screen.
I found that default THREE.PointsMaterial does not support lighting (the points are visible with or without adding lights to the scene).
So I tried to implement a custom ShaderMaterial. But I could not find a way to add lighting to the rendered object.
Here is a sample of what my code is doing:
Sample App on StackBlitz showing my current attempt
In this code, I am using sample values for point cloud data, normals and color but everything else is similar to my actual application. I can see the 3D object, but need more proper lighting using normals.
I need help or guidance to implement the following:
Add lighting to custom shader material. I have Googled and tried many things, no success so far.
Using normals, show the effects of lighting (In this sample code, the normals are fixed to Y-axis direction, but I am calculating them based on some vector logic in actual application). So calculating normals is already done, but I want to use them to show light shine/shading effect in the custom shader material.
And in this sample, color attribute is set to fixed red color, but in actual application I am able to apply colors using UV range from a texture to color attribute.
Please advise how/if I can get lighting based on normals for Point Cloud. Thanks.
Note: I looked at this Stackoveflow question but it only deals with changing the alpha/transparency of points and not lighting.
Adding lighting to a custom material is a very complex process. Especially since you could use Phong, Lambert, or Physical lighting methods, and there's a lot of calculations that need to pass from the vertex to the fragment shader. For instance, this segment of shader code is just a small part of what you'd need.
Instead of trying to re-create lighting from scratch, I recommend you create a PlaneGeometry with the material you'd like (Phong, Lambert, Physical, etc...) and use an InstancedMesh to create thousands of instances, just like in this example.
Based on that example, the pseudo-code of how you could achieve a similar effect is something like this:
const count = 100000;
const geometry = new PlaneGeometry();
const material = new THREE.MeshPhongMaterial();
mesh = new THREE.InstancedMesh( geometry, material, count );
mesh.instanceMatrix.setUsage( THREE.DynamicDrawUsage ); // will be updated every frame
scene.add( mesh );
const dummy = new THREE.Object3D();
update() {
// Sets the rotation so it's always perpendicular to camera
dummy.lookAt(camera);
// Updates positions of each plane
for (let i = 0; i < count; i++){
dummy.position.set( x, y, z );
dummy.updateMatrix();
mesh.setMatrixAt( i ++, dummy.matrix );
}
}
The for() loop would be the most expensive part of each frame, so if you need to update it on each frame, you might want to calculate this in the vertex shader, but that's another question altogether.
Let's say I have a vertical list of meshes created from PlaneBufferGeometry with ShaderMaterial. The meshes are distributed vertically and evenly spaced.
The list will have two states:
Displaying the meshes as they are
Displaying meshes with each object's vertices transformed by the vertex shader to the same arbitrary value, let's say z = -50. This gives a zoomed out effect and the user can scroll through this list (in the code we do this by moving the camera y position)
In my app I'm trying to make my mouseover events work for the second state but it's tricky since the GPU transforms the vertices so the updated vertices are not reflected in the attributes on the JS side.
*Note I've looked into GPU picking and do not want to use it because I believe there should be a simpler way to do this without render targets
Attempted Solution
My current approach is to manually change the boundingBox of each plane when we are in the second state like so:
var box = new THREE.Box3().setFromObject(plane);
box.min.z = -50;
box.max.z = -50;
plane.geometry.boundingBox = box;
And then to change the boundingSphere's center to have the same z position of -50 after computing it.
I did this approach because I looked into the Raycaster and Mesh code for THREE.js and it seems like they check both boundingSphere and boundingBox for object intersections. So I thought if I modified both of them to reflect the transforms done by the GPU, the raycaster would work fine but it doesn't seem to be working for me.
The relevant raycaster code is here:
// mouse being vec2 of normalized coordinates and camera being a perspective camera
raycaster.setFromCamera( mouse, camera );
const intersects = raycaster.intersectObjects( planes );
Possible Theories
The only thing I can think of that's wrong about this approach is maybe I'm not projecting the mouse coords right? Since all the objects now lie on the plane z = -50 would I need to project those mouse coordinates to that plane?
Inspired by the link posted by #prisoner849 I found a working solution to just create additional transparent planes equal to the number of planes in the scene. In these planes, I set the z position to -50 and just intersect with these when in state #2.
A bit hacky, but works for now.
I've been struggling with this one for hours, and found nothing either in the docs or here on SO that would point me to the right direction to achieve what I aim at.
I'm loading a scene containing several meshes. The first one is used as an actual mesh, rendered on the scene, the other ones are just used as morph targets (their geometries, properly speaking).
loader.load("scene.json", function (loadedScene) {
camera.lookAt( scene.position );
var basis = loadedScene.getObjectByName( "Main" ).geometry;
var firstTarget = loadedScene.getObjectByName( "Target1" ).geometry;
// and so on for the rest of the "target" meshes
basis.morphTargets[0] = {name: 'fstTarget', vertices: firstTarget.vertices};
var MAIN = new THREE.Mesh(basis);
This works very well, and I can morph the MAIN mesh with no hassle by playing with the influence values. The differences between the basis mesh and the target are not huge, basically they're just XY adjustments (2D shape variations).
Now, I'm using a textures material: UVs are properly projected (Blender export) and the result is nice with the MAIN mesh as is.
The problem comes when the basis shape is morphed towards a target geometry: as expected, the texture (UVs) adapts automatically, but this is not what I need to achieve => I'd need to have the UVs "morph" towards the morph target's UVs for the texture to look the same.
Here is an example of what I have now (left: basis mesh, right: morphTargetInfluences = 1 for the first morph target)
morph target and texture
What I'd like to have is the exact same texture projection on the final, morphed mesh...
I can't figure out how to do that the right way. Should I reassign the target UVs to the MAIN mesh (and how would I do that)?
The result would be like having a cloth below which a shape is morphed, and the cloth being "shrinked-wrapped" all the time against that underlying shape => you can actually see the shape changes, but the cloth itself is not deformed, just wrapping itself properly and consistently around the shape...
Any help would be much appreciated! Thanks in advance :)
I'm trying to make a Plane to always face the camera or another moving object but I want the Plane to only rotate on 1 axis. How can I use the lookAt function to make it only rotate side ways without tilting to look up or down at the moving object?
thanks, I managed to solve it easily by just keeping the y position of the rotating object constant.
if(planex){
var yaw_control = controls.getYawObject();
pos = new THREE.Vector3( yaw_control.position.x, planex.position.y, yaw_control.position.z );
planex.lookAt(pos);
}
http://www.lighthouse3d.com/opengl/billboarding/index.php?billCyl
maybe this article of any help for you. You are looking for those cylindrical billboards i think but read up from the first page ;) You can modify the specific mesh matrix yourself, although i am not sure if this is the most efficient way. I also did this myself once.
Get the camera look vec:
three.js set and read camera look vector
Then get the camera upVec and afterwards get the cross prodcut of those = rightVec according to the article above.
using those vectors, you can fill in a new Three.Matrix4() like explained in the article and then replace the meshes matrix with the newly created one. As I said, i am not quite into the matrix stuff in three.js but this works but it is probably not that efficient.
For this to work you will have to deactive the meshes auto matrix update with
mesh.matrixAutoUpdate = false;
I am using the version THREE.js57. I want to hide selected face at run time. Is this possible in three.js
Thanks & Regards
Indeed this is possible, you'll want to look into the Raycaster library, here's the high level steps
unproject your mouse click coordinates into the 3D scene.
cast rays into your scene and return an intersected array of collided objects
this intersected object will have the affected face and faceIndex as parameters
on collision turn the face # faceIndex transparency to 0
Have a look at these doc pages:
http://threejs.org/docs/#Reference/Core/Projector
http://threejs.org/docs/#Reference/Core/Raycaster
And this example for a start:
https://github.com/mrdoob/three.js/blob/master/examples/canvas_interactive_cubes.html
Edit:
Alright, well to then hide the face you can have a peak at this other SO post:
Can I hide faces of a mesh in three.js?
The gist is you have a multimaterial object, the first material is your default, and a second material that's fully opaque. Then when you intersect you set the face to use the second materialIndex. Anyway, the above link should do the job. Off to up vote that response. :)