在scenekit中的obj模型上应用适当的饰面？

Question

我正在尝试使用 Scenekit (ARIkit iOS) 在 .obj 模型上应用金属度贴图。 不幸的是，它显示的是垂直线。

请参考下面的代码，我还附上了截图以便正确理解。

模型经过 UV 展开以解决模型中的平铺问题，并附上所有材料以供查看。

对象网址： https : //s3.ap-south-1.amazonaws.com/p9-platform/product/4f800e4c-52cd-4167-a7c3-6ba5703df7e7.obj

func loadTexture(forMaterial material: SCNMaterial, withFinish finish:FinishModel, forDispatchGroup disPatchGroup:DispatchGroup) {

    concurrentQueue.async {
        if material.lightingModel != .physicallyBased {
            material.lightingModel = .physicallyBased
        }
    }
    if let finishMap = finish.finishMap {
      if let diffuseTexturePath = finishMap.diffuseMapUrl {
            disPatchGroup.enter()
            self.dataProvider.fetchTextureFile(forpath: diffuseTexturePath, successBlock: { (success, imageObject) in
                //self.viewController?.report_memory()
                material.diffuse.contents = nil
                material.diffuse.contents = imageObject
                disPatchGroup.leave()
            }, failureBlock: { (error) in
                disPatchGroup.leave()
            })
        }

       if let metalTexturePath = finishMap.metalnessMapUrl {
            disPatchGroup.enter()
            self.dataProvider.fetchTextureFile(forpath: metalTexturePath, successBlock: { (success, imageObject) in
               // self.viewController?.report_memory()
               material.metalness.contents = nil
                material.metalness.contents = imageObject
                disPatchGroup.leave()
            }, failureBlock: { (error) in
                disPatchGroup.leave()
            })
        }

        if let roughnessTexturePath = finishMap.roughnessMapUrl {
            disPatchGroup.enter()
            self.dataProvider.fetchTextureFile(forpath: roughnessTexturePath, successBlock: { (success, imageObject) in
               // self.viewController?.report_memory()
                material.roughness.contents = nil
                material.roughness.contents = imageObject
                disPatchGroup.leave()
            }, failureBlock: { (error) in
                disPatchGroup.leave()
            })
        }

        if let normalTexturePath = finishMap.normalMapUrl {
            disPatchGroup.enter()
            self.dataProvider.fetchTextureFile(forpath: normalTexturePath, successBlock: { (success, imageObject) in
                material.normal.contents = nil
               // self.viewController?.report_memory()
                material.normal.contents = imageObject
                disPatchGroup.leave()
            }, failureBlock: { (error) in
                disPatchGroup.leave()
            })
        }

    }
}