when I set a point light at a THREE.BoxGeometry object it looks like this:
THREE.BoxGeometry with point light
var light = new THREE.PointLight (0xffffff, 1, 100);
light.position.set (10, 10, 10);
scene.add (light);
var geometry = new THREE.BoxGeometry (1, 1, 1);
var material = new THREE.MeshPhongMaterial ();
var cube = new THREE.Mesh (geometry, material);
scene.add (cube);
When I now set a point light at a THREE.PolyhedronGeometry object it looks like this:
THREE.PolyhedronGeometry with point light
var light = new THREE.PointLight (0xffffff, 1, 100);
light.position.set (10, 10, 10);
scene.add (light);
var geometry = new THREE.PolyhedronGeometry (vertices, faces, 1, 0);
var vertices = [-1,-1,-1,1,-1,-1,1,1,-1,-1,1,-1,-1,-1,1,1,-1,1,1,1,1,-1,1,1];
var faces = [2,1,0,0,3,2,0,4,7,7,3,0,0,1,5,5,4,0,1,2,6,6,5,1,2,3,7,7,6,2,4,5,6,6,7,4];
var material = new THREE.MeshPhongMaterial ();
var cube = new THREE.Mesh (geometry, material);
scene.add (cube);
I want to know, where this behaviour comes from and how I can manage to make polyhedrons' faces behave as nice as boxs?
I read that it might be related to geometry.computeFaceNormals().
So I tried it out, but it doesn't make any difference.
when something is different with how light behaves on a surface, first candidates to look at are normals
this is true for the box face
boxGeometry.faces[i].normal.equals(boxGeometry.faces[i].vertexNormals[j]);//true
so box has only simple normal for each face
the polyhedron has different face normal from the vertex normals
polyhedronGeo.faces[i].normal.equals(polyhedronGeo.faces[i].vertexNormals[j]);//not true
and some of the vertex normals are not equal among each other
polyhedronGeo.faces[i].vertexNormals[j].equals(polyhedronGeo.faces[i].vertexNormals[k]);
//not true for some j,k
that is why the light looks ~shadowy - normal is interpolated for the shader from vertexNormals
to modify the polyhedron to look like box just change the vertex notmals to match the face normal
as for
geometry.computeFaceNormals();
it will only compute the face normals, not the vertexNormals
there is another function
geometry.computeVertexNormals();
but that would create vertex normals as are in polyhedron
Thanks Derte. Your reflection got me closer to the point. So with advanced keywords I found this: https://github.com/mrdoob/three.js/issues/1982
The answer to my question is this line, flattening shading for "free forms":
material.shading = THREE.FlatShading;
Related
I need to move an object along directional vector through some distance. I fount translateOnAxis(vector, distance) of Object3D class. But I'm not able to understand how it works.
I've an object- sphere. I'm scaling it to look like ellipse. And setting position and direction. Now I need this object to move in the same direction which I'm setting it to, through some distance. When I apply it, I can't see the object. Can anybody suggest how it can be achieved?
var geometry = new THREE.SphereGeometry( radius, 64, 64, 0, -Math.PI );
geometry.applyMatrix( new THREE.Matrix4().makeScale( 1, 1, zScale ); //scaling it to look like ellipse
var direction = new THREE.Vector3( xDir, yDir, zDir);
var ellipse = new THREE.Mesh( geometry, material );
ellipse.lookAt(direction);
ellipse.position.set( xPos, yPos, zPos);
ellipse.translateOnAxis(direction, distance);
Your pasted code is buggy.
You're missing a ) on your applyMatrix line.
Are you using a debugger and observing console errors/warnings?
I'm a newbie in three.js (and in stackoverflow).
I try to find answer but I'm not able to do this simple things.
I'm playing with Helpers and Plane.
I want to create a Plane (and it's PlaneHelper), and draw an arbitrary vector on this Plane.
All is right if the plane's distance from origin is set to 0.
If I give a distance to the plane, the vector is not on the plane.
Here is the commented code I use for this little experiment.
Projecting both the origin and the vector on the plane I was convinced that arrowHelper_Point remained on the plane, but it's not.
Where is my mistake? I can not understand it.
// Define ARROW_LENGTH to display ArrowHelper
const ARROW_LENGTH = 5;
// Point (0,0,0)
var origin = new THREE.Vector3(0, 0, 0);
// Axes helper in (0,0,0)
var axesHelperOrigin = new THREE.AxesHelper(100);
scene.add(axesHelperOrigin);
// Define a plane by the normal, color and distance from (0,0,0)
var vectorNormal = {
normal: new THREE.Vector3(1, 1, 0).normalize(),
color: "rgb(255, 255, 0)",
colorNormal: "rgb(255,100,0)",
colorVector: "rgb(194, 27, 255)",
distance: -3,
};
// Create Plane from the normal and distance
var plane = new THREE.Plane(vectorNormal.normal, vectorNormal.distance);
// Add PlaneHelper to scene
var planeHelper = new THREE.PlaneHelper(plane, 100, vectorNormal.color);
scene.add(planeHelper);
// Add ArrowHelper to display normal
// Find the projection of origin on plane
var originOnPlane = plane.projectPoint(origin);
var arrowHelper_Normal = new THREE.ArrowHelper(vectorNormal.normal, originOnPlane, ARROW_LENGTH, vectorNormal.colorNormal);
scene.add(arrowHelper_Normal);
// Define a point "random"
var point = new THREE.Vector3(5, -2, 6);
// Project the point on plane
var pointOnPlane = plane.projectPoint(point);
// Draw ArrowHelper to display the pointOnPlane, from originOnPlane
var arrowHelper_Point = new THREE.ArrowHelper(pointOnPlane.normalize(), originOnPlane, ARROW_LENGTH, vectorNormal.colorVector);
scene.add(arrowHelper_Point);
EDIT: OK, I think I find the error.
Looking at this Get direction between two 3d vectors using Three.js?
I need the vector between the two points:
var dir=new THREE.Vector3();
dir.subVectors(pointOnPlane,originOnPlane).normalize();
And use dir as the arrow direction.
Sorry for asking an obviously thing.
Looking at this Get direction between two 3d vectors using Three.js?
I need the vector between the two points:
var dir=new THREE.Vector3();
dir.subVectors(pointOnPlane,originOnPlane).normalize();
And use dir as the arrow direction.
I´m very new to three js and I want to create a half Cylinder as roof.
var geometry = new THREE.CylinderGeometry(100,100,150);
var material = new THREE.MeshNormalMaterial();
var cylinder = new THREE.Mesh( geometry, material);
scene.add(cylinder);
This is the Basic Cylinder but unfortunately I couldn´t find an specific answer to a half cylinder yet.
Is it possible to create this with vertices?
The last 2 params of CylinderGeometry constructor allows this. For example:
var geometry = new THREE.CylinderGeometry(100,100,150, 8, 1, false, 0, Math.PI);
0 is the start angle and Math.PI is the end angle; i.e. half of a circle.
I've done a terrain using planegeometry object. I set a vertexes' y coordinate to bump my terrain. Then I added a directional light to my scene and see that there is no shadowing of the "hills" etc.
I added also a sphere and noticed that there is also no shadow on this terrain.
var light = new THREE.DirectionalLight(0xffffff, 1);
light.castShadow = true;
light.shadowCameraVisible = true;
light.position.set(-300, 120, -200); // CHANGED
scene.add(light);
scene.add( new THREE.DirectionalLightHelper(light, 0.2) );
Directional light with sphere above the terrain
But when I replaced directional light by a spotlight I've seen shadowing on a terrain that I want to have.
var slight = new THREE.SpotLight(0xffffff,1);
slight.position.set(-100,60,100);
slight.shadowCameraVisible = true;
scene.add(slight);
scene.add(new THREE.SpotLightHelper(slight, 0.5));
Spotlight with terrain
So the questions are:
how can I do a light that looks like sunshine so the terrain will be not plane color but depend on light? (in future it will be a part of a real city)
what should I do to see the objects' shadows on the terrain? (from fiddle example: sphere's shadow)
Thanks
You are modifying the vertices of your terrain. When you do so, you have to also modify the vertex normals. One way to do that is like so:
geometry.computeVertexNormals();
To create shadows you must enable them.
renderer.shadowMap.enabled = true;
three.js r.130
I am creating a scene & have used a boolean function to cut out holes in my wall. However the lighting reveals that the resultant shapes have messed up faces. I want the surface to look like one solid piece, rather than fragmented and displaying lighting backwards. Does anyone know what could be going wrong with my geometry?
The code that booleans objects is as follows:
//boolean subtract two shapes, convert meshes to bsps, subtract, then convert back to mesh
var booleanSubtract = function (Mesh1, Mesh2, material) {
//Mesh1 conversion
var mesh1BSP = new ThreeBSP( Mesh1 );
//Mesh2 conversion
var mesh2BSP = new ThreeBSP( Mesh2 );
var subtract_bsp = mesh1BSP.subtract( mesh2BSP );
var result = subtract_bsp.toMesh( material );
result.geometry.computeVertexNormals();
return result;
};
I have two lights in the scene:
var light = new THREE.DirectionalLight( 0xffffff, 0.75 );
light.position.set( 0, 0, 1 );
scene.add( light );
//create a point light
var pointLight = new THREE.PointLight(0xFFFFFF);
// set its position
pointLight.position.x = 10;
pointLight.position.y = 50;
pointLight.position.z = 130;
// add to the scene
scene.add(pointLight);
EDIT: Using WestLangley's suggestion, I was able to partially fix the wall rendering. And by using material.wireframe=true; I can see that after the boolean operation my wall faces are not merged. Is there a way to merge them?
Your problems are due to two issues.
First, you should be using FlatShading.
Second, as explained in this stackoverflow post, MeshLambert material only calculates the lighting at each vertex, and interpolates the color across each face. MeshPhongMaterial calculates the color at each texel.
You need to use MeshPhongMaterial to avoid the lighting artifacts you are seeing.
three.js r.68