Add plug-in to read PLY files

Seems to work fine.

Contributes to issue CURA-6739.

plugins/PLYReader/PLYReader.py

@@ -0,0 +1,76 @@
+# Copyright (c) 2019 Ultimaker B.V., fieldOfView
+# Cura is released under the terms of the LGPLv3 or higher.
+
+# The _toMeshData function is taken from the AMFReader class which was built by fieldOfView.
+
+import numpy  # To create the mesh data.
+import os.path  # To create the mesh name for the resulting mesh.
+import trimesh  # To load the PLY files into a Trimesh.
+
+from UM.Mesh.MeshData import MeshData, calculateNormalsFromIndexedVertices
+from UM.Mesh.MeshReader import MeshReader
+from UM.MimeTypeDatabase import MimeTypeDatabase, MimeType
+
+from cura.CuraApplication import CuraApplication
+from cura.Scene.BuildPlateDecorator import BuildPlateDecorator
+from cura.Scene.CuraSceneNode import CuraSceneNode
+from cura.Scene.SliceableObjectDecorator import SliceableObjectDecorator
+
+##  Class that leverages Trimesh to read PLY files (Stanford Triangle Format).
+class PLYReader(MeshReader):
+    def __init__(self) -> None:
+        super().__init__()
+
+        self._supported_extensions = [".ply"]
+        MimeTypeDatabase.addMimeType(
+            MimeType(
+                name = "application/x-ply",  # Wikipedia lists the MIME type as "text/plain" but that won't do as it's not unique to PLY files.
+                comment = "Stanford Triangle Format",
+                suffixes = ["ply"]
+            )
+        )
+
+    ##  Reads the PLY file.
+    #   \param file_name The file path of the PLY file. This is assumed to be a
+    #   PLY file; it's not checked again.
+    #   \return A scene node that contains the PLY file's contents.
+    def _read(self, file_name: str) -> CuraSceneNode:
+        mesh = trimesh.load(file_name)
+        mesh.merge_vertices()
+        mesh.remove_unreferenced_vertices()
+        mesh.fix_normals()
+        mesh_data = self._toMeshData(mesh)
+
+        file_base_name = os.path.basename(file_name)
+        new_node = CuraSceneNode()
+        new_node.setMeshData(mesh_data)
+        new_node.setSelectable(True)
+        new_node.setName(file_base_name)
+        new_node.addDecorator(BuildPlateDecorator(CuraApplication.getInstance().getMultiBuildPlateModel().activeBuildPlate))
+        new_node.addDecorator(SliceableObjectDecorator())
+        return new_node
+
+    def _toMeshData(self, tri_node: trimesh.base.Trimesh) -> MeshData:
+        tri_faces = tri_node.faces
+        tri_vertices = tri_node.vertices
+
+        indices = []
+        vertices = []
+
+        index_count = 0
+        face_count = 0
+        for tri_face in tri_faces:
+            face = []
+            for tri_index in tri_face:
+                vertices.append(tri_vertices[tri_index])
+                face.append(index_count)
+                index_count += 1
+            indices.append(face)
+            face_count += 1
+
+        vertices = numpy.asarray(vertices, dtype = numpy.float32)
+        indices = numpy.asarray(indices, dtype = numpy.int32)
+        normals = calculateNormalsFromIndexedVertices(vertices, indices, face_count)
+
+        mesh_data = MeshData(vertices = vertices, indices = indices, normals = normals)
+        return mesh_data

plugins/PLYReader/__init__.py

@@ -0,0 +1,21 @@
+# Copyright (c) 2019 Ultimaker
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from . import PLYReader
+
+from UM.i18n import i18nCatalog
+i18n_catalog = i18nCatalog("uranium")
+
+
+def getMetaData():
+    return {
+        "mesh_reader": [
+            {
+                "extension": "ply",
+                "description": i18n_catalog.i18nc("@item:inlistbox", "PLY File")
+            }
+        ]
+    }
+
+def register(app):
+    return {"mesh_reader": PLYReader.PLYReader()}

plugins/PLYReader/plugin.json

@@ -0,0 +1,7 @@
+{
+    "name": "PLY Reader",
+    "author": "Ultimaker B.V.",
+    "version": "1.0.0",
+    "description": "Provides support for reading PLY files.",
+    "api": "6.0.0"
+}