3D model removing some part and changing texture of a specific vertices

Question

I am trying to crop and edit a 3d model which I created using photogrammetry ,I tried multiple solutions but seems like none of that worked , posting in urge of guidance , let me address what I did , I tried to select the vertices where user tap and removed that from my geometry but that did not work , also I tried to make a new geometry with a texture added to specific part of the geometry, but this all didn't worked

 func cropModelIs(node: SCNNode, geometry: SCNGeometry, selectedVertices: [SCNVector3]) {
        var newVertices: [SCNVector3] = []
        var newIndices: [UInt32] = []
        var vertexIndexMap = [Int: Int]()
        var newVertexIndex = 0
        
        // Iterate through the existing vertices and exclude selected vertices
        for (vertexIndex, vertex) in getVerticesFromGeometry(geometry: geometry).enumerated() {
            if !selectedVertices.contains(vertex) {
                newVertices.append(vertex)
                vertexIndexMap[vertexIndex] = newVertexIndex
                newVertexIndex += 1
            }
        }
        
        // Iterate through the existing triangles and update their indices
        for element in geometry.elements {
            guard element.primitiveType == .triangles else {
                continue
            }
            
            let indices: [UInt32] = element.data.withUnsafeBytes { dataPtr in
                Array(dataPtr.bindMemory(to: UInt32.self))
            }
            
            
            // Create new triangle indices by mapping old indices to new indices
            for i in stride(from: 0, to: indices.count, by: 3) {
                let oldIndices = [indices[i], indices[i + 1], indices[i + 2]]
                
                // Check if all vertices in the triangle are valid (not removed)
                let shouldKeepTriangle = oldIndices.allSatisfy { vertexIndexMap.keys.contains(Int($0)) }
                
                if shouldKeepTriangle {
                    // All vertices are valid, add the triangle with updated indices
                    let newTriangleIndices = oldIndices.map { UInt32(vertexIndexMap[Int($0)]!) }
                    
                    
                    // Make sure the new indices form a valid triangle
                    if newTriangleIndices[0] != newTriangleIndices[1] && newTriangleIndices[1] != newTriangleIndices[2] && newTriangleIndices[2] != newTriangleIndices[0] {
                        newIndices.append(contentsOf: newTriangleIndices)
                    }
                }
            }


        }
        
        // Create a new geometry with the updated vertices and indices
        let newGeometry = SCNGeometry(sources: [SCNGeometrySource(vertices: newVertices)], elements: [SCNGeometryElement(indices: newIndices, primitiveType: .triangles)])
      //  var meshGeometry = SCNGeometry()
        // Apply materials to the new geometry (not shown in your code)
        
        // Update the geometry of the original node (assuming it's the right hierarchy)
        if let imageURL = getImageFromMeshTexture(node: originalNode, materialIndex: 0){
            let newGeometryIs = applyTextureToGeometry(geometry: newGeometry, imageURL: imageURL)
            
            // Now you can create a new node using the new geometry
           // let newNode = SCNNode(geometry: newGeometryIs)
            originalNode.childNode(withName: "Geometry", recursively: true)?.childNodes[0].geometry = newGeometryIs
            // Replace the original node with the new node
//            if let parentNode = originalNode.parent {
//                originalNode.removeFromParentNode()
//                parentNode.addChildNode(newNode)
//            }
        }

    }