I have a 3d figure (in this case a hammerhead Shark) that has been loaded with:
shark3d= readOBJ("19412_Hammerhead_Shark_v2.OBJ")
This 3d object has been successfully added to an rgl scene using:
shade3d(shark3d, material = list(col = "darkgray"))
However, I would like to add this shade3d object to an specific coordinate inside the rgl scene.
Thanks for your help.
You can use translate3d and related functions to move "mesh3d" objects around in the scene. For example,
shade3d(translate3d(shark3d, x = 10, y = 20, z = 30),
material = list(col = "darkgray"))
or
shark3d %>%
translate3d(x = 10, y = 20, z = 30) %>%
shade3d(material = list(col = "darkgray"))
will move the (0,0,0) coordinate of the shape to (10,20,30).
Related
What I'm trying to achieve is a rotation of the geometry around pivot point and make that the new definition of the geometry. I do not want te keep editing the rotationZ but I want to have the current rotationZ to be the new rotationZ 0.
This way when I create a new rotation task, it will start from the new given pivot point and the newly given rad.
What I've tried, but then the rotation point moves:
// Add cube to do calculations
var box = new THREE.Box3().setFromObject( o );
var size = box.getSize();
var offsetZ = size.z / 2;
o.geometry.translate(0, -offsetZ, 0)
// Do ratation
o.rotateZ(CalcUtils.degreeToRad(degree));
o.geometry.translate(0, offsetZ, 0)
I also tried to add a Group and rotate that group and then remove the group. But I need to keep the rotation without all the extra objects. The code I created
var box = new THREE.Box3().setFromObject( o );
var size = box.size();
var geometry = new THREE.BoxGeometry( 20, 20, 20 );
var material = new THREE.MeshBasicMaterial( { color: 0xcc0000 } );
var cube = new THREE.Mesh( geometry, material );
cube.position.x = o.position.x;
cube.position.y = 0; // Height / 2
cube.position.z = -size.z / 2;
o.position.x = 0;
o.position.y = 0;
o.position.z = size.z / 2;
cube.add(o);
scene.add(cube);
// Do ratation
cube.rotateY(CalcUtils.degreeToRad(degree));
// Remove cube, and go back to single object
var position = o.getWorldPosition();
scene.add(o)
scene.remove(cube);
console.log(o);
o.position.x = position.x;
o.position.y = position.y;
o.position.z = position.z;
So my question, how do I save the current rotation as the new 0 rotation point. Make the rotation final
EDIT
I added an image of what I want to do. The object is green. I have a 0 point of the world (black). I have a 0 point of the object (red). And I have rotation point (blue).
How can I rotate the object around the blue point?
I wouldn't recommend updating the vertices, because you'll run into trouble with the normals (unless you keep them up-to-date, too). Basically, it's a lot of hassle to perform an action for which the transformation matrices were intended.
You came pretty close by translating, rotating, and un-translating, so you were on the right track. There are some built-in methods which can help make this super easy.
// obj - your object (THREE.Object3D or derived)
// point - the point of rotation (THREE.Vector3)
// axis - the axis of rotation (normalized THREE.Vector3)
// theta - radian value of rotation
// pointIsWorld - boolean indicating the point is in world coordinates (default = false)
function rotateAboutPoint(obj, point, axis, theta, pointIsWorld){
pointIsWorld = (pointIsWorld === undefined)? false : pointIsWorld;
if(pointIsWorld){
obj.parent.localToWorld(obj.position); // compensate for world coordinate
}
obj.position.sub(point); // remove the offset
obj.position.applyAxisAngle(axis, theta); // rotate the POSITION
obj.position.add(point); // re-add the offset
if(pointIsWorld){
obj.parent.worldToLocal(obj.position); // undo world coordinates compensation
}
obj.rotateOnAxis(axis, theta); // rotate the OBJECT
}
After this method completes, the rotation/position IS persisted. The next time you call the method, it will transform the object from its current state to wherever your inputs define next.
Also note the compensation for using world coordinates. This allows you to use a point in either world coordinates or local space by converting the object's position vector into the correct coordinate system. It's probably best to use it this way any time your point and object are in different coordinate systems, though your observations may differ.
As a simple solution for anyone trying to quickly change the pivot point of an object, I would recommend creating a group and adding the mesh to the group, and rotating around that.
Full example
const geometry = new THREE.BoxGeometry();
const material = new THREE.MeshBasicMaterial({ color: 0xff0000 });
const cube = new THREE.Mesh(geometry, material);
scene.add(cube)
Right now, this will just rotate around its center
cube.rotation.z = Math.PI / 4
Create a new group and add the cube
const group = new THREE.Group();
group.add(cube)
scene.add(group)
At this point we are back where we started. Now move the mesh:
cube.position.set(0.5,0.5,0)
Then move the group
group.position.set(-0.5, -0.5, 0)
Now use your group to rotate the object:
group.rotation.z = Math.PI / 4
I am working on a program in three.js. So I have a particle system loaded from a LAS file. It has a coordinate system. I have added a functionality which enables user to click on a particle, and it would add a bounding box to the scene. My aim is to find which particles lie inside this bounding box.
Code for adding bounding box at point p clicked by user:
var cubeGeometry = new THREE.BoxGeometry( 1, 1, 1 );
var cubeMaterial = new THREE.MeshLambertMaterial( { color:
0xffff00,wireframe: true } );
var cube = new THREE.Mesh( cubeGeometry, cubeMaterial );
cube.position.x = p.x;
cube.position.y = p.y;
cube.position.z = p.z;
scene.add(cube);
But I am facing an issue. The box created has a different coordinate axis orientation than particle system. It's Y axis is oriented in direction of particle system's Z axis. This causes containsPoint method to give wrong answer.
How to solve this issue?
Try this:
var e = new THREE.Euler( - Math.PI / 2, 0, 0 );
p.applyEuler( e );
This will apply a rotation of 90 degrees around the x-axis or a conversion from Z-up to Y-up.
I have created an object, a cone, and have located it, orientated it, and then translated it along its axis z. Well, now I want to retrieve its position in x, y and z and store the information in an array for later use.
var cone = new THREE.Mesh(coneGeometry, coneMaterial);
var φ = wup[iter].Latitude*Math.PI/180;
var λ = - wup[iter].Longitude*Math.PI/180;
//φ phi lat λ lambda lon
cone.position.set (
Math.cos(λ) * 90 * Math.cos(φ),
Math.sin(φ) * 90,
Math.sin(λ) * 90 * Math.cos(φ)
);
cone.lookAt( new THREE.Vector3(0,0,0) );
cone.translateZ( - earthRadius * réduc);
wup[iter].x = cone.x;
wup[iter].y = cone.y;
wup[iter].z = cone.z; /
The problem is that cone.x does not contain anything.
Based on philipp's indication, and on the reply to a neighboring question of mine, here is the code that worked:
wup[iter].x = cone.position.x;
wup[iter].y = cone.position.y;
wup[iter].z = cone.position.z;
cone, as a geometry, has a vector called position associated to it with coordinates. Consequently, retrieving the coordinates of the geometry implies calling the coordinates of its vector position.
Made a simple jsFiddle example to illustrate a problem.
I'm trying to fit object's bounding box to screen from different camera positions. In example in dat.GUI panel you can change camera position and then click button fit to screen.
When changing y and z (positive) camera positions to find camera's top and bottom properties code below is used
var top = boundingBox.max.y * Math.cos(angleToZAxis) + boundingBox.max.z * Math.sin(angleToZAxis); // line 68
var bottom boundingBox.min.y * Math.cos(angleToZAxis) + boundingBox.min.z * Math.sin(angleToZAxis);
I would like to know how I can include camera's x position and negative positions in this calculation, what is the math behind this. Should I use rotation matrix and how to use it?
Or maybe it can be achieved in some simple way with threejs methods, can't figure out, tried the code below but something is wrong:
var matrix = new THREE.Matrix4();
matrix.lookAt ( this.camera.position, new THREE.Vector3(0, 0, 0), new THREE.Vector3(0, 1, 0) );
var bbMax = boundingBox.max.clone().applyMatrix4(matrix);
var bbMin = boundingBox.min.clone().applyMatrix4(matrix)
;
to fit an orthographic camera you have to simply change its zoom and position
you can calculate zoom from the bounding box of your object
(I used the boxes from geometry, but you will have to take in account matrices of the objects in group; I used them because .setFromObject was not returning consistent value)
Canvas3D.prototype.fitToScreen = function() {
this.group.children[0].geometry.computeBoundingBox();
var boundingBox = this.group.children[0].geometry.boundingBox.clone();
this.group.children[1].geometry.computeBoundingBox();
boundingBox.union(this.group.children[1].geometry.boundingBox);
var rotation = new THREE.Matrix4().extractRotation(this.camera.matrix);
boundingBox.applyMatrix4(rotation);
this.camera.zoom = Math.min(this.winWidth / (boundingBox.max.x - boundingBox.min.x),
this.winHeight / (boundingBox.max.y - boundingBox.min.y)) * 0.95;
this.camera.position.copy(boundingBox.center());
this.camera.updateProjectionMatrix();
this.camera.updateMatrix();
};
using this will not work in your fiddle because you are using OrbitControls and they rotate camera on update based on their own state - so either update that state or create your own controls
also either move camera back after
this.camera.position.copy(boundingBox.center());
or set near plane to -1000 to avoid having cut object
this.camera = new THREE.OrthographicCamera(this.winWidth / -2,
this.winWidth / 2 , this.winHeight / 2, this.winHeight / -2, -10000, 10000);
EDIT
now i see that you dont want to just fit the object but the whole box...
to do so an easy way is to project the points of the box and get the distances of extremes in pixels, then you can set ortho camera directly
boundingBox = new THREE.Box3().setFromObject(this.group);
//take all 8 vertices of the box and project them
var p1 = new THREE.Vector3(boundingBox.min.x,boundingBox.min.y,boundingBox.min.z).project(this.camera);
var p2 = new THREE.Vector3(boundingBox.min.x,boundingBox.min.y,boundingBox.max.z).project(this.camera);
var p3 = new THREE.Vector3(boundingBox.min.x,boundingBox.max.y,boundingBox.min.z).project(this.camera);
var p4 = new THREE.Vector3(boundingBox.min.x,boundingBox.max.y,boundingBox.max.z).project(this.camera);
var p5 = new THREE.Vector3(boundingBox.max.x,boundingBox.min.y,boundingBox.min.z).project(this.camera);
var p6 = new THREE.Vector3(boundingBox.max.x,boundingBox.min.y,boundingBox.max.z).project(this.camera);
var p7 = new THREE.Vector3(boundingBox.max.x,boundingBox.max.y,boundingBox.min.z).project(this.camera);
var p8 = new THREE.Vector3(boundingBox.max.x,boundingBox.max.y,boundingBox.max.z).project(this.camera);
//fill a box to get the extremes of the 8 points
var box = new THREE.Box3();
box.expandByPoint(p1);
box.expandByPoint(p2);
box.expandByPoint(p3);
box.expandByPoint(p4);
box.expandByPoint(p5);
box.expandByPoint(p6);
box.expandByPoint(p7);
box.expandByPoint(p8);
//take absolute value because the points already have the correct sign
var top = box.max.y * Math.abs(this.camera.top);
var bottom = box.min.y * Math.abs(this.camera.bottom);
var right = box.max.x * Math.abs(this.camera.right);
var left = box.min.x * Math.abs(this.camera.left);
this.updateCamera(left, right, top, bottom);
this code also stretches the view to fit exactly into the window so you will have to check for the aspect ratio and change one size accordingly, but that should be trivial
I'm trying to make a static 3D prism out of point clouds with specific numbers of particles in each. I've got the the corner coordinates of each side of the prism based on the angle of turn, and tried spawning the particles in the area bound by these coordinates. Instead, the resulting point clouds have kept only the bottom left coordinate.
Screenshot: http://i.stack.imgur.com/uQ7Q8.png
I've tried to set the rotation of each cloud object such that their edges meet, but they will rotate only around the world centre. I gather this is something to do with rotation matrices and Euler angles, but, having been trying to work them out for 3 solid days, I've despaired. (I'm a sociologist, not a dev, and haven't touched graphics before this project.)
Please help? How do I set the rotation on each face of the prism? Or maybe there is a more sensible way to get the particles to spawn in the correct area in the first place?
The code:
// draw the particles
var n = 0;
do {
var geom = new THREE.Geometry();
var material = new THREE.PointCloudMaterial({size: 1, vertexColors: true, color: 0xffffff});
for (i = 0; i < group[n]; i++) {
if (geom.vertices.length < group[n]){
var particle = new THREE.Vector3(
Math.random() * screens[n].bottomrightback.x + screens[n].bottomleftfront.x,
Math.random() * screens[n].toprightback.y + screens[n].bottomleftfront.y,
Math.random() * screens[n].bottomrightfront.z + screens[n].bottomleftfront.z);
geom.vertices.push(particle);
geom.colors.push(new THREE.Color(Math.random() * 0x00ffff));
}
}
var system = new THREE.PointCloud(geom, material);
scene.add(system);
**// something something matrix Euler something?**
n++
}
while (n < numGroups);
I've tried to set the rotation of each cloud object such that their
edges meet, but they will rotate only around the world centre.
It is true they only rotate around 0,0,0. The simple solution then is to move the object to the center, rotate it, and then move it back to its original position.
For example (Code not tested so might take a bit of tweaking):
var m = new THREE.Matrix4();
var movetocenter = new THREE.Matrix4();
movetocenter.makeTranslation(-x, -y, -z);
var rotate = new THREE.Matrix4();
rotate.makeRotationFromEuler(); //Build your rotation here
var moveback = new THREE.Matrix4();
moveback .makeTranslation(x, y, z);
m.multiply(movetocenter);
m.multiply(rotate);
m.multiply(moveback);
//Now you can use geometry.applyMatrix(m)