.ply (polygon) format file issue in ios 14 - ios

Question

My app generates ply files after scanning objects. After ios 14 update the color of my 3d models does not load correctly. Also I am unable to view ply files in xcode (works fine in preview).
Anyone know the workaround to this problem?
I tired reading ply file content and display vertices and faces in scene geometry but it takes too long to load a file.
Apparently creating mdlAsset() throws some Metal warning and the mesh color does not show up properly.
Here are the sample images from ios 13 and 14 preview in sceneKit.

Answer 1

same problem,i found it is a SceneKit's bug, i had a solution that read .ply file with C, and creat a SCNGeometry instance with data, main code:
first we need read vertexCount and faceCount in .ply file (my file is ASCII format,so, )
bool readFaceAndVertexCount(char* filePath, int *vertexCount, int *faceCount);
example:
bool readFaceAndVertexCount(char* filePath, int *vertexCount, int *faceCount) {
char data[100];
FILE *fp;
if((fp = fopen(filePath,"r")) == NULL)
{
printf("error!");
return false;
}
while (!feof(fp))
{
fgets(data,1024,fp);
unsigned long i = strlen(data);
data[i - 1] = '\0';
if (strstr(data, "element vertex") != NULL) {
char *res = strtok(data," ");
while (res != NULL) {
res = strtok(NULL, " ");
if (res != NULL) {
*vertexCount = atoi(res);
}
}
}
if (strstr(data, "element face") != NULL) {
char *res = strtok(data," ");
while (res != NULL) {
res = strtok(NULL, " ");
if (res != NULL) {
*faceCount = atoi(res);
}
}
}
if (*faceCount > 0 && *vertexCount > 0) {
break;
}
}
fclose(fp);
return true;
}
2, read data to array:
in .c
// you need to implement with your files
bool readPlyFile(char* filePath, const int vertexCount, int faceCount, float *vertex, float *color, int *elment)
in .swift:
var vertex: [Float] = Array.init(repeating: 0, count: Int(vertexCount) * 3)
var color: [Float] = Array.init(repeating: 0, count: Int(vertexCount) * 3)
var face: [Int32] = Array.init(repeating: 0, count: Int(faceCount) * 3)
readPlyFile(UnsafeMutablePointer<Int8>(mutating: url.path),vertexCount,faceCount,&vertex,&color,&face)
3 creat a custom SCNGeometry:
let positionData = NSData.init(bytes: vertex, length: MemoryLayout<Float>.size * vertex.count)
let vertexSource = SCNGeometrySource.init(data: positionData as Data, semantic: .vertex, vectorCount: Int(vertexCount), usesFloatComponents: true, componentsPerVector: 3, bytesPerComponent: MemoryLayout<Float>.size, dataOffset: 0, dataStride: MemoryLayout<Float>.size * 3)
let colorData = NSData.init(bytes: color, length: MemoryLayout<Float>.size * color.count)
let colorSource = SCNGeometrySource.init(data: colorData as Data, semantic: .color, vectorCount: Int(vertexCount), usesFloatComponents: true, componentsPerVector: 3, bytesPerComponent: MemoryLayout<Float>.size, dataOffset: 0, dataStride: MemoryLayout<Float>.size * 3)
let indexData = NSData(bytes: face, length: MemoryLayout<Int32>.size * face.count)
let element = SCNGeometryElement(data: indexData as Data, primitiveType: SCNGeometryPrimitiveType.triangles, primitiveCount: Int(faceCount), bytesPerIndex: MemoryLayout<Int32>.size)
let gemetry = SCNGeometry.init(sources: [vertexSource,colorSource], elements: [element])
let node = SCNNode.init(geometry: gemetry)
let scene = SCNScene.init()
node.geometry?.firstMaterial?.cullMode = .back
node.geometry?.firstMaterial?.isDoubleSided = true
scene.rootNode.addChildNode(node)
scnView.scene = scene
it work! and faster!