xeokit 3D Collision Utilities

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Spatial searches and collision testing with 3D k-d trees, rays and boundaries

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A KdTree3 organizes items with 3D axis-aligned boundaries into a fast spatial search index that allows us efficiently search it for items whose boundaries intersect given boundaries and volumes.

This module provides the following functions to build KdTree3s:

• createPrimsKdTree3: Creates a KdTree3 containing primitives from the given set of geometry arrays, organized by their coordinate 3D boundaries.
• createSceneObjectPrimsKdTree3: Creates a KdTree3 containing primitives belonging to the given SceneObjects, organized by their World-space 3D boundaries.
• createSceneObjectsKdTree3: Create a KdTree3 containing the given SceneObjects, organized by their World-space 3D boundaries.

This module provides the following functions to search KdTree3s:

• searchKdTree3WithAABB: Finds the items that collide with a given 3D axis-aligned boundary (AABB).
• searchKdTree3WithFrustum: Finds the items that collide with a given 3D frustum volume.
• searchKdTree3WithRay: Finds the items that collide with a given 3D ray.

With these components, applications can implement (at least):

• Frustum3 culling for SceneObjects
• Ray-picking SceneObjects
• Marquee selection of SceneObjects

Installation

npm install @xeokit/kdtree3
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Dependencies

• "@xeokit/scene"
• "@xeokit/core"
• "@xeokit/math"
• "@xeokit/boundaries"

Usage

Querying for SceneObjects that intersect a 3D World-space boundary:

import {Scene} from "@xeokit/scene";
import {SDKError} from "@xeokit/core";
import {TrianglesPrimitive} from "@xeokit/constants";
import {KdTree3, searchKdTree3WithAABB} from "@xeokit/kdtree3";

const scene = new Scene();

const sceneModel = scene.createModel({
     id: "myModel"
});

if (sceneModel instanceof SDKError) {
     console.log(sceneModel.message);

} else {

    sceneModel.createGeometry({
        id: "theGeometry", primitive: TrianglesPrimitive,
        positions: [10.07, 0, 11.07, 9.58, 3.11, 11.07, 8.15, ..],
        indices: [21, 0, 1, 1, 22, 21, 22, 1, 2, 2, 23, 22, 23, ..]
    });

    sceneModel.createLayerMesh({
        id: "redLegMesh", geometryId: "theGeometry",
        position: [-4, -6, -4], scale: [1, 3, 1], rotation: [0, 0, 0], color: [1, 0.3, 0.3]
    });

    sceneModel.createLayerMesh({
        id: "greenLegMesh", geometryId: "theGeometry", position: [4, -6, -4], scale: [1, 3, 1],
        rotation: [0, 0, 0], color: [0.3, 1.0, 0.3]
    });

    sceneModel.createLayerMesh({
        id: "blueLegMesh", geometryId: "theGeometry", position: [4, -6, 4],  scale: [1, 3, 1],
        rotation: [0, 0, 0], color: [0.3, 0.3, 1.0]
    });

    sceneModel.createLayerMesh({
        id: "yellowLegMesh",  geometryId: "theGeometry", position: [-4, -6, 4], scale: [1, 3, 1],
        rotation: [0, 0, 0], color: [1.0, 1.0, 0.0]
    });

    sceneModel.createLayerMesh({
        id: "tableTopMesh", geometryId: "theGeometry", position: [0, -3, 0], scale: [6, 0.5, 6],
        rotation: [0, 0, 0], color: [1.0, 0.3, 1.0]
    });

    sceneModel.createObject({ id: "redLegSceneObject", meshIds: ["redLegMesh"] });
    sceneModel.createObject({ id: "greenLegSceneObject", meshIds: ["greenLegMesh"] });
    sceneModel.createObject({ id: "blueLegSceneObject", meshIds: ["blueLegMesh"] });
    sceneModel.createObject({ id: "yellowLegSceneObject", meshIds: ["yellowLegMesh"] });
    sceneModel.createObject({ id: "tableTopSceneObject", meshIds: ["tableTopMesh"] });

    sceneModel.build()

        .then(() => {

            const kdTree = createSceneObjectsKdTree3(Object.values(scene.objects));

            const sceneObjects = searchKdTree3WithAABB({
                kdTree,
                aabb : [0, 0, 0, 10, 10, 10]
            });

            const sceneObjects2 = searchKdTree3WithFrustum({
                kdTree,
                frustum: new Frustum3( .. )
            });

            const objectMap = {};

            for (let i = 0, len = sceneObjects.length; i < len; i++) {
                const sceneObject = sceneObjects[i];
            }

            const redLegSceneObject = objectMap["redLegSceneObject"];
            const greenLegSceneObject = objectMap["greenLegSceneObject"];
            const tableTopSceneObject = objectMap["tableTopSceneObject"];
        });
}
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