How about placing a particle on the top layer of a mesh at a random location?

I am struggling to place a particle on the top side of a custom mesh using Three.js. Most tutorials I've come across only demonstrate adding particles to cubes or spheres, leaving me with no solution for my unique shape. How can I successfully position a particle at a random point on the upper surface of my mesh?

var extrusionSettings = {
      bevelEnabled: false,
      extrudeMaterial: 1,   amount:3, 
    };

var Hexagon=new Array();
Hexagongeometry[0]= new Array();
Hexagongeometry[0].push(new THREE.Vector3(-3,  0.0, 0.0)); 
Hexagongeometry[0].push(new THREE.Vector3( -3,  3, 0.0)); 
Hexagongeometry[0].push(new THREE.Vector3( 0,  5, 0.0)); 
Hexagongeometry[0].push(new THREE.Vector3( 3,  3, 0.0)); 
Hexagongeometry[0].push(new THREE.Vector3( 3,  0, 0.0));
Hexagongeometry[0].push(new THREE.Vector3( 0,  -3, 0.0));
Hexagongeometry[0].push(new THREE.Vector3( -3,  0, 0.0));

var HexagonShape=new Array();
HexagonShape[0] = new THREE.Shape( Hexagongeometry[0] );

var HexagonExtrude=new Array();
HexagonExtrude[0] = new THREE.ExtrudeGeometry( HexagonShape[0],      extrusionSettings );
var material=new Array();
material[0] = new THREE.MeshBasicMaterial( { color: 0xffff00 } );

var Hexagon=new Array();
Hexagon[0] = new THREE.Mesh( HexagonExtrude[0],material[0] );
scene.add(Hexagon[0]);

var particleMaterial = new THREE.ParticleBasicMaterial({  size: 2, color:  0xff0000, transparency: true, alphaTest: 0.5 });
var particle = new THREE.ParticleSystem( HexagonExtrude[0], particleMaterial );   
scene.add( particle);

Despite numerous attempts, I have been unsuccessful in placing the particle on any part of my mesh, specifically hexagon [0]. The techniques demonstrated in tutorials work well for basic shapes like cubes or spheres but are not applicable to my intricate mesh structure. It would greatly facilitate if someone could guide me on how to randomly position multiple particles on various points of my mesh.

I am still learning Three.js and apologize for any language barriers. Your assistance is much appreciated.

http://jsfiddle.net/6z8f3eq3/

Answer №1

To find a solution, let's break down the problem into smaller parts.

When dealing with a complex mesh, start by choosing a random polygon and determining a point on that polygon. It's important to know which way the polygon is facing to select a point "above" it. The best approach for each step will vary depending on the characteristics of your mesh and your specific goal.

Firstly, consider how you'll choose the polygon. You could simply use the list, but if your mesh contains polygons of varying sizes, you may want to prioritize larger ones. This decision marks the first set of choices.

Moving on to selecting a random point on the polygon, particularly when working with triangles, barycentric coordinates are a good starting point. They're easy to apply and provide even distributions (though other methods exist).

Lastly, if your mesh includes surface normals, consider adding a fraction of the surface normal to the previously determined point. For meshes with face normals, this approach will yield a different distribution compared to smooth normals. To further refine this process, you may want to incorporate raycasts to prevent intersection with neighboring polygons based on the mesh's shape.

If unsure, start by implementing the simplest version of these three steps and then refine them as needed.

I can't provide code directly, but verbal instructions are most suitable for addressing this type of question. Best of luck!

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

How come a colon within a function's body does not result in an error in JavaScript?

During my coding journey, I encountered a situation where I was attempting to return an object from an arrow function. However, I noticed that the code snippet below was simply returning undefined. After some investigation, I determined that the curly br ...

Node.js encounters a conflict between route names and directory names

Can you use the same name for both a route and a directory in a Node.js project? For example: require("./test")(router); And inside the test.js file: app.get("/test", function(req, res) {}); Also, test is a directory in the same project. When attempti ...

Does the built-in waiting mechanism in Protractor automatically handle promises?

While browsing through Stack Overflow, I stumbled upon this response in a discussion about Protractor tests and asynchronous solutions: 'AFAIK expect waits internally for the related promises.' I have tried looking through the official Protract ...

If I remove my project but still have it saved on my GitHub, do I need to reinstall all the dependencies or can I simply run npm install again?

I have a question regarding my deleted project that is saved on GitHub. If I formatted my PC and lost the project but it's still on GitHub, do I need to reinstall all the dependencies or can I just run 'npm install'? The project has dependen ...

The feature to prevent multiple selections in JSTree is not functioning as expected

Incorporating JSTree into my application involves the code below. this.CreateTreeView = function () { $('#jstree_demo_div').jstree({ 'core': { 'multiple': false, 'data': [ ...

What is the best way to transform object request data into a string in an Express application using Node.js

I am trying to save the request data from app.get('/') to a variable, but I keep getting an error "TypeError: Converting circular structure to JSON". var express = require('express') var app = express() var bodyParser = require('b ...

Node.js: Error - Module 'html' not found

Currently, I am utilizing Node.js and attempting to exclusively serve HTML files without any Jade or EJS engines. Below is the code for my entry point (index.js): var express = require('express'); var bodyParser = require('body-parser&apo ...

The issue at hand is that one of the JavaScript buttons is functioning properly, while the other is not playing the video as intended. What steps can

I've been working on a script for my school project website that should make buttons play videos, but I'm running into an issue where it only works for the first button (btn). Programming isn't my strong suit, and I put this together based o ...

Regular expression to validate the proper file naming convention: 1201_17-11-2015.zip

I am looking to verify if a specific file name follows the correct format. Here is the required format: first four numbers_two numbers-two numbers-4 numbers.zip To achieve this, I will need a regular expression. An example of a file name in JavaScript ...

Having trouble setting the selected option in Jquery by value?

I have exhausted all options found on the internet. What could I be overlooking? The desired option is not getting selected. Here is the troublesome section of code. I have also included some other attempts that I have commented out. If it helps, this li ...

Transition the object in smoothly after the slide has changed

How can I make the h4 tags fade in after the divs slide into view, while also adding the class "current" to each visible slide? Check out the example on JSFiddle here. <div class="slider"> <div class="slides"> <div class="slide ...

Changing buffer from base64 to UTF-8 encoding in Node.js

My application imports messages from the Notes folder of Gmail using the imap npm module. When following the example on their GitHub page, all message contents are read into a buffer: stream.on('data', function(chunk) { count += chunk.len ...

Style the div element with CSS

Is there a way to style a div element within an HTML document using Sencha framework? I have specific CSS properties that I would like to apply to my div. #logo{ position:absolute; top:20%; left:0%; } Below is a snippet of my Sencha code: Ex ...

Utilize the power of DOJO JavaScript to implement Reverse AJAX functionality in

Exploring the possibility of implementing Reverse AJAX with the DOJO Javascript framework. Curious if DOJO has built-in support for this feature like other frameworks such as DWR. I am currently working with the most recent version of DOJO - any guidance ...

Enhance the display in Angular2

Just started working with Angular 2 and I've encountered a problem. I have an API that loads a JavaScript file in my project. The issue is, I need to use this JS file and cannot modify it. Essentially, this JS file has some methods that make AJAX call ...

Setting the Height of a Fixed Element to Extend to the Bottom of the Browser Window

I currently have a webpage layout featuring a header at the top, a fixed sidebar on the left side, and main content displayed on the right. A demo version of this layout can be viewed at http://jsbin.com/iqibew/3. The challenge I'm facing is ensuring ...

Manipulating the display style of an element without using jQuery

Could anyone assist me with this issue? I am currently facing a challenge in making the following script functional. It is intended to hide the button after it has been clicked. The script is being called through Ajax and PHP, so I am unable to utilize jQ ...

What is the best way to retrieve the value of the first name using Protractor?

Is there a way to store the value of the first name using a protractor script? The first name is set when the user logs in and corresponds to the name of the logged-in user. I am wondering if this can be done utilizing by.addLocator(). Here is the tag tha ...

Best practices for managing an array of buttons and handling click events in ReactJs

While working on my react class component, I encountered an issue. The alert popup keeps appearing constantly without any button click as soon as the component renders. onHandleOnClick(data, e) { console.log(data); alert("got it" + data); } rend ...

Pressing the button will allow you to select and copy the text within the

I am looking to incorporate a mock-chat feature into my website. The concept is to type something on the website, then click a button next to it which will move the text to a frame above. I attempted this using a textarea and even found a code for selectin ...