CODEWITHSUNDEEP
javascript3dthree.jslinear-algebraplane
P.S.
P.S.

Reputation: 95

Three.js - PlaneGeometry from Math.Plane

I am trying to draw a least squares plane through a set of points in Three.js. I have a plane defined as follows:

var plane = new THREE.Plane();
plane.setFromNormalAndCoplanarPoint(normal, point).normalize();

My understanding is that I need to take that plane and use it to come up with a Geometry in order to create a mesh to add to the scene for display:

var dispPlane = new THREE.Mesh(planeGeometry, planeMaterial);
scene.add(dispPlane);

I've been trying to apply this answer to get the geometry. This is what I came up with:

plane.setFromNormalAndCoplanarPoint(dir, centroid).normalize();
planeGeometry.vertices.push(plane.normal);
planeGeometry.vertices.push(plane.orthoPoint(plane.normal));
planeGeometry.vertices.push(plane.orthoPoint(planeGeometry.vertices[1]));
planeGeometry.faces.push(new THREE.Face3(0, 1, 2));

planeGeometry.computeFaceNormals();
planeGeometry.computeVertexNormals();

But the plane is not displayed at all, and there are no errors to indicate where I may have gone wrong.

So my question is, how can I take my Math.Plane object and use that as a geometry for a mesh?

Upvotes: 3

Views: 6853

Answers (2)

larsmoa
larsmoa

Reputation: 12942

var material = ...;
var plane = new THREE.Plane(...);

// Align to plane
var geometry = new THREE.PlaneGeometry(100, 100);
var mesh = new THREE.Mesh(geometry, material);
mesh.translate(plane.coplanarPoint());
mesh.quaternion.setFromUnitVectors(new THREE.Vector3(0,0,1), plane.normal);

Note that Plane.coplanarPoint() simply returns -normal*constant, so it might be a better option to use Plane.projectPoint() to determine a center that is "close to" an arbitrary point.

Upvotes: 2

msun
msun

Reputation: 841

This approach should create a mesh visualization of the plane. I'm not sure how applicable this would be towards the least-squares fitting however.

 // Create plane
var dir = new THREE.Vector3(0,1,0);
var centroid = new THREE.Vector3(0,200,0);
var plane = new THREE.Plane();
plane.setFromNormalAndCoplanarPoint(dir, centroid).normalize();

// Create a basic rectangle geometry
var planeGeometry = new THREE.PlaneGeometry(100, 100);

// Align the geometry to the plane
var coplanarPoint = plane.coplanarPoint();
var focalPoint = new THREE.Vector3().copy(coplanarPoint).add(plane.normal);
planeGeometry.lookAt(focalPoint);
planeGeometry.translate(coplanarPoint.x, coplanarPoint.y, coplanarPoint.z);

// Create mesh with the geometry
var planeMaterial = new THREE.MeshLambertMaterial({color: 0xffff00, side: THREE.DoubleSide});
var dispPlane = new THREE.Mesh(planeGeometry, planeMaterial);
scene.add(dispPlane);

Upvotes: 5

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