How to find a specfic object in a merged buffergeometry?

Questions
,
1

For the performance purpose, in my case I mergerd cell shape as one buffergeometry. My question is while I raycaster one of cells and get the following content

distance: 0.5163975193122629
face: t {a: 5434, b: 5433, c: 5440, normal: t, vertexNormals: Array(0), …}
faceIndex: 4738
object: Un {uuid: ‘04E2D3A2-59F6-4CE0-AF94-003A0E9E13DD’, name: ‘rois’, type: ‘Mesh’, parent: e, children: Array(0), …}
point: t {x: 0.16790426007605952, y: 0.3279409435830404, z: 0, isVector3: true}
uv: t {x: 0.16790426007605952, y: 0.3279409435830404, isVector2: true}
[[Prototype]]: Object

Can I use faceIndex to get the exacti one of the cell?

I created a range dictionary by myself like this

roisDictionary.push([roisName, count - rois.data[roisName].length, rois.data[roisName].length]);

So I can compare whether the faceIndex is in one of the ranges

let faceIndex = genes.raycaster_points.filter(x => x.object.type === 'Mesh')[0].faceIndex;
roisDictionary.forEach(item => {
   if (faceIndex > item[1] && faceIndex < (item[1] + item[2])) {
        mouseHoveredRoisIdx = faceIndex;
         if (!cellName.includes(item[0])) {
             cellName.push(item[0]);
             mouseHoveredRoisName = item[0];
             generatorHoveredCell(item[0]);
       }
    }
})

I did the implementation like this, but while the mouse hoverd the cell, it is the another cell, seeems this is not the correct way to use faceIndex.

2

Depending on your exact use-case, I think it’s easier to keep the original (unmerged) set of meshes in a separate group or scene that are not rendered but solely used for ray-testing.

So you render the merged geometries, but keep the original intact for “game logic”.