CODEWITHSUNDEEP
three.jsraycasting
Danko
Danko

Reputation: 69

Ray does not accurately determine the intersection

I want to find point of intersection curve and line. Created raycast, but it doesn't work well. The point of the ray is far from the actual intersection.

Webgl 1, threejs 0.109

        var sartPoint = new THREE.Vector3( -30, -50, 0 );
        var endPoint = new THREE.Vector3( 50, 80, 0 );
        var geometry = new THREE.Geometry();
        geometry.vertices.push(sartPoint);
        geometry.vertices.push(endPoint);
        var materialTmp = new THREE.LineBasicMaterial( { color: 0xffffff, linewidth: 5 } );
        var itemTmp = new THREE.Line( geometry, materialTmp );
        _this.add( itemTmp, 'lines' );
        scene.updateMatrixWorld()

       var curve = new THREE.EllipseCurve(
          0,  0,            // ax, aY
          10, 10,           // xRadius, yRadius
          0,  2 * Math.PI,  // aStartAngle, aEndAngle
          false,            // aClockwise
          0                 // aRotation
        );

        var points = curve.getPoints( 10 );
        var geometry = new THREE.BufferGeometry().setFromPoints( points );
        var material = new THREE.LineBasicMaterial( { color : 0xff00ff } );
        var ellipse = new THREE.Line( geometry, material );
        scene.add( ellipse );

        var raycaster = new THREE.Raycaster(sartPoint, endPoint.clone().normalize());

        var intersects = raycaster.intersectObject( ellipse );
        console.log(intersects);
        if(intersects.length > 0){
          // FIRST dot of intersect
          var dotGeometry2 = new THREE.Geometry();
          dotGeometry2.vertices.push(intersects[0].point);
          var dotMaterial2 = new THREE.PointsMaterial( { size: 5, color: 0x00ff00 } );
          var dot2 = new THREE.Points( dotGeometry2, dotMaterial2 );
          _this.add( dot2, 'points' );
        }

enter image description here

Upvotes: 1

Views: 83

Answers (2)

Danko
Danko

Reputation: 69

It is work if curve.getPoints( 10 ); When curve.getPoints( 100 ); That doesn't work.

enter image description here

Upvotes: 0

prideout
prideout

Reputation: 3019

The second argument to the Raycaster constructor is a direction vector. Instead of:

endPoint.clone().normalize()

I think you want:

endPoint.clone().sub(startPoint).normalize()

Upvotes: 1

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