adding a lot of custom nodes to scene takes a long time to load

Question

I am building a scenekit app however I am having issues with some of the finer details. I created a scene and I am adding custom geometry to it and it works fine until the number of nodes gets to about 100. It is ideal to add a large number of nodes to a scene and is there a cleaner way to do it?

    for i in 0..<modelArr!.count {
        let model = modelArr![i]

        let pos: [SCNVector3] = Parser.loadPosition(model)
        let norm:[SCNVector3] = Parser.loadNormals(model)
        let ind:[CInt] = Parser.loadIndices(model)

        let src = SCNGeometrySource(vertices: pos, count: pos.count)
        let norSrc = SCNGeometrySource(normals: norm, count: norm.count)

        //let indexData = NSData(bytes: ind, length: sizeof(CInt) * ind.count)
        let indexData = NSData(bytes: Array<CInt>(0..<CInt(ind.count)),
                               length: ind.count * sizeof(Float))

        let element = SCNGeometryElement(data: indexData,
                                         primitiveType: .Triangles,
                                         primitiveCount: pos.count / 3,
                                         bytesPerIndex: sizeof(Float))

        let geo = SCNGeometry(sources: [src, norSrc], elements: [element])
        let material = SCNMaterial()
        material.diffuse.contents = UIColor.redColor()
        material.specular.contents = UIColor.whiteColor()

        let cubeNode = SCNNode(geometry: geo)
        cubeNode.geometry?.firstMaterial = material
        emptyNode.addChildNode(cubeNode)
    }
    scn.rootNode.addChildNode(emptyNode)        
}

I have a large number of indices, normals, and positions.

score 0 · Answer 1 · edited May 23 '17 at 12:32

One thing you can do is split up the load using Grand Central Dispatch, and dispatch_apply (to distribute the computation) and a serial dispatch queue (to update emptyNode with each new cubeNode. A thorough explanation of this approach (using a different problem space, but still trying to speed up an expensive operation) can be found in this answer.

What will help a lot is to do the loading in a separate utility program. After you've created your scene, archive it. Embed that scene in your user-facing program. Unarchiving the scene is much faster than creating it from scratch.

adding a lot of custom nodes to scene takes a long time to load

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