diff --git a/meshroom/__init__.py b/meshroom/__init__.py
index 874719e012..b84d461485 100644
--- a/meshroom/__init__.py
+++ b/meshroom/__init__.py
@@ -160,10 +160,15 @@ def addToEnvPath(var, val, index=-1):
 
         env = {
             "PATH": aliceVisionBinDir,
-            "QT_PLUGIN_PATH": [qtPluginsDir],
-            "QML2_IMPORT_PATH": [os.path.join(qtPluginsDir, "qml")]
         }
 
+        # Only add Qt plugin/QML paths if the directories actually exist
+        if os.path.isdir(qtPluginsDir):
+            env["QT_PLUGIN_PATH"] = [qtPluginsDir]
+            qmlImportDir = os.path.join(qtPluginsDir, "qml")
+            if os.path.isdir(qmlImportDir):
+                env["QML2_IMPORT_PATH"] = [qmlImportDir]
+
         for key, value in env.items():
             logging.debug(f"Add to {key}: {value}")
             addToEnvPath(key, value, 0)
@@ -196,6 +201,13 @@ def addToEnvPath(var, val, index=-1):
     addToEnvPath("PATH", os.environ.get("ALICEVISION_BIN_PATH", ""))
     if sys.platform == "win32":
         addToEnvPath("PATH", os.environ.get("ALICEVISION_LIBPATH", ""))
+    elif sys.platform == "darwin":
+        aliceVisionLibPath = os.environ.get("ALICEVISION_LIBPATH", "")
+        addToEnvPath("DYLD_FALLBACK_LIBRARY_PATH", aliceVisionLibPath)
+        if rootDir:
+            aliceVisionLibDir = os.path.join(rootDir, "aliceVision", "lib")
+            if os.path.isdir(aliceVisionLibDir):
+                addToEnvPath("DYLD_FALLBACK_LIBRARY_PATH", aliceVisionLibDir)
     else:
         addToEnvPath("LD_LIBRARY_PATH", os.environ.get("ALICEVISION_LIBPATH", ""))
 
@@ -203,4 +215,7 @@ def addToEnvPath(var, val, index=-1):
 os.environ["QML_XHR_ALLOW_FILE_READ"] = '1'
 os.environ["QML_XHR_ALLOW_FILE_WRITE"] = '1'
 os.environ["PYSEQ_STRICT_PAD"] = '1'
-os.environ["QSG_RHI_BACKEND"] = "opengl"
+if sys.platform == "darwin":
+    os.environ.setdefault("QSG_RHI_BACKEND", "metal")
+else:
+    os.environ["QSG_RHI_BACKEND"] = "opengl"
diff --git a/meshroom/core/cgroup.py b/meshroom/core/cgroup.py
index 7d78a8f895..6e580d2841 100755
--- a/meshroom/core/cgroup.py
+++ b/meshroom/core/cgroup.py
@@ -63,6 +63,12 @@ def parseNumericList(numericListString):
 # Try to retrieve limits of cores for the current process' cgroup
 def getCgroupCpuCount():
 
+    # On non-Linux systems (macOS, Windows), cgroups don't exist.
+    # Fall back to os.cpu_count() to detect available cores.
+    import sys
+    if sys.platform != "linux":
+        return os.cpu_count() or -1
+
     # First of all, get pid of process
     pid = os.getpid()
 
diff --git a/meshroom/core/desc/attribute.py b/meshroom/core/desc/attribute.py
index 4a41c3d4e6..6dd0ccd4a0 100644
--- a/meshroom/core/desc/attribute.py
+++ b/meshroom/core/desc/attribute.py
@@ -237,10 +237,13 @@ class GroupAttribute(Attribute):
     @deprecated.depreciateParam("group", "Param 'group' on {name} should not be used anymore. Please use 'commandLineGroup' instead")
     def __init__(self, items, name, label=None, description=None, group="allParams", commandLineGroup=_setParamSentinel, 
                  advanced=False, semantic="",  enabled=True, joinChar=" ", brackets=None, visible=True,
-                 exposed=False):
+                 exposed=False, groupDesc=None):
         """
         :param items: the description of the Attributes composing this group
+        :param groupDesc: deprecated alias for 'items'
         """
+        if items is None and groupDesc is not None:
+            items = groupDesc
         self._items = items
         self._joinChar = joinChar
         self._brackets = brackets
diff --git a/meshroom/ui/app.py b/meshroom/ui/app.py
index 0b42b4ca7c..32ff30cbca 100644
--- a/meshroom/ui/app.py
+++ b/meshroom/ui/app.py
@@ -277,6 +277,20 @@ def __init__(self, inputArgs):
             qInstallMessageHandler(MessageHandler.handler)
 
         self.engine.addImportPath(qmlDir)
+        # Add PySide6's bundled QML modules path (Qt3D, QtQuick.Scene3D, etc.)
+        pyside6QmlPath = os.path.join(os.path.dirname(QtCore.__file__), "Qt", "qml")
+        if os.path.isdir(pyside6QmlPath):
+            self.engine.addImportPath(pyside6QmlPath)
+
+        # Add qtAliceVision QML plugins from the AliceVision bundle
+        for envVar in ("AV_BUNDLE", "MESHROOM_INSTALL_DIR"):
+            bundleBase = os.environ.get(envVar, "")
+            if bundleBase:
+                pluginsPath = os.path.join(bundleBase, "PlugIns")
+                if os.path.isdir(pluginsPath):
+                    self.engine.addImportPath(pluginsPath)
+                    logging.info(f"Added QML import path: {pluginsPath}")
+                    break
 
         # expose available node types that can be instantiated
         self.engine.rootContext().setContextProperty("_nodeTypes", {n: {"category": pluginManager.getRegisteredNodePlugins()[n].nodeDescriptor.category} for n in sorted(pluginManager.getRegisteredNodePlugins().keys())})
diff --git a/meshroom/ui/components/scene3D.py b/meshroom/ui/components/scene3D.py
index afeac42f50..0a0419b04d 100644
--- a/meshroom/ui/components/scene3D.py
+++ b/meshroom/ui/components/scene3D.py
@@ -1,6 +1,7 @@
+import struct
 from math import acos, pi, sqrt, atan2, cos, sin, asin
 
-from PySide6.QtCore import QObject, Slot, QSize, Signal, QPointF
+from PySide6.QtCore import QObject, Slot, QSize, Signal, QPointF, QByteArray
 from PySide6.Qt3DCore import Qt3DCore
 from PySide6.Qt3DRender import Qt3DRender
 from PySide6.QtGui import QVector3D, QQuaternion, QVector2D, QVector4D, QMatrix4x4
@@ -52,6 +53,47 @@ def vertexColorCount(self, entity):
             count += sum([attr.count() for attr in geo.attributes() if attr.name() == "vertexColor"])
         return count
 
+    @Slot(Qt3DCore.QEntity)
+    def ensureNormals(self, entity):
+        """
+        Add default normal attributes to geometries that don't have them.
+        This prevents Metal RHI pipeline crashes when built-in Qt3D materials
+        (which require vertexNormal) are used with meshes lacking normals.
+        """
+        for geo in entity.findChildren(Qt3DCore.QGeometry):
+            hasNormals = any(attr.name() == "vertexNormal" for attr in geo.attributes())
+            if hasNormals:
+                continue
+
+            # Find the vertexPosition attribute to get vertex count
+            posAttr = None
+            for attr in geo.attributes():
+                if attr.name() == "vertexPosition":
+                    posAttr = attr
+                    break
+            if not posAttr:
+                continue
+
+            vertexCount = posAttr.count()
+
+            # Create a buffer filled with (0, 1, 0) default normals
+            normalData = QByteArray(struct.pack('<fff', 0.0, 1.0, 0.0) * vertexCount)
+            normalBuffer = Qt3DCore.QBuffer(geo)
+            normalBuffer.setData(normalData)
+
+            # Create the normal attribute
+            normalAttr = Qt3DCore.QAttribute(geo)
+            normalAttr.setName("vertexNormal")
+            normalAttr.setVertexBaseType(Qt3DCore.QAttribute.Float)
+            normalAttr.setVertexSize(3)
+            normalAttr.setAttributeType(Qt3DCore.QAttribute.VertexAttribute)
+            normalAttr.setBuffer(normalBuffer)
+            normalAttr.setByteStride(3 * 4)  # 3 floats * 4 bytes
+            normalAttr.setByteOffset(0)
+            normalAttr.setCount(vertexCount)
+
+            geo.addAttribute(normalAttr)
+
 
 class TrackballController(QObject):
     """
diff --git a/meshroom/ui/qml/Viewer3D/BoundingBox.qml b/meshroom/ui/qml/Viewer3D/BoundingBox.qml
index 543d90d345..34cb9aae1c 100644
--- a/meshroom/ui/qml/Viewer3D/BoundingBox.qml
+++ b/meshroom/ui/qml/Viewer3D/BoundingBox.qml
@@ -84,6 +84,24 @@ Entity {
                             ])
                     }
                 }
+                Attribute {
+                    attributeType: Attribute.VertexAttribute
+                    vertexBaseType: Attribute.Float
+                    vertexSize: 3
+                    count: 24
+                    name: defaultNormalAttributeName
+                    buffer: Buffer {
+                        data: {
+                            var f32 = new Float32Array(24 * 3)
+                            for (var i = 0; i < 24; i++) {
+                                f32[3 * i] = 0.0
+                                f32[3 * i + 1] = 1.0
+                                f32[3 * i + 2] = 0.0
+                            }
+                            return f32
+                        }
+                    }
+                }
                 boundingVolumePositionAttribute: boundingBoxPosition
             }
         }
diff --git a/meshroom/ui/qml/Viewer3D/Grid3D.qml b/meshroom/ui/qml/Viewer3D/Grid3D.qml
index 06ec8fdc0c..03e2a41f91 100644
--- a/meshroom/ui/qml/Viewer3D/Grid3D.qml
+++ b/meshroom/ui/qml/Viewer3D/Grid3D.qml
@@ -46,6 +46,25 @@ Entity {
                         }
                     }
                 }
+                Attribute {
+                    id: gridNormal
+                    attributeType: Attribute.VertexAttribute
+                    vertexBaseType: Attribute.Float
+                    vertexSize: 3
+                    count: gridPosition.count
+                    name: defaultNormalAttributeName
+                    buffer: Buffer {
+                        data: {
+                            var f32 = new Float32Array(gridPosition.count * 3)
+                            for (var i = 0; i < gridPosition.count; i++) {
+                                f32[3 * i] = 0.0
+                                f32[3 * i + 1] = 1.0
+                                f32[3 * i + 2] = 0.0
+                            }
+                            return f32
+                        }
+                    }
+                }
                 boundingVolumePositionAttribute: gridPosition
             }
         },
diff --git a/meshroom/ui/qml/Viewer3D/Locator3D.qml b/meshroom/ui/qml/Viewer3D/Locator3D.qml
index f08a92b230..c65c83ed11 100644
--- a/meshroom/ui/qml/Viewer3D/Locator3D.qml
+++ b/meshroom/ui/qml/Viewer3D/Locator3D.qml
@@ -30,6 +30,23 @@ Entity {
                             ])
                     }
                 }
+                Attribute {
+                    attributeType: Attribute.VertexAttribute
+                    vertexBaseType: Attribute.Float
+                    vertexSize: 3
+                    count: 6
+                    name: defaultNormalAttributeName
+                    buffer: Buffer {
+                        data: new Float32Array([
+                            0.0, 1.0, 0.0,
+                            0.0, 1.0, 0.0,
+                            0.0, 1.0, 0.0,
+                            0.0, 1.0, 0.0,
+                            0.0, 1.0, 0.0,
+                            0.0, 1.0, 0.0
+                            ])
+                    }
+                }
                 Attribute {
                     attributeType: Attribute.VertexAttribute
                     vertexBaseType: Attribute.Float
diff --git a/meshroom/ui/qml/Viewer3D/MaterialSwitcher.qml b/meshroom/ui/qml/Viewer3D/MaterialSwitcher.qml
index 9a9614befa..fe89a46d1f 100644
--- a/meshroom/ui/qml/Viewer3D/MaterialSwitcher.qml
+++ b/meshroom/ui/qml/Viewer3D/MaterialSwitcher.qml
@@ -95,9 +95,9 @@ Entity {
     DiffuseMapMaterial {
         id: textured
         objectName: "TexturedMaterial"
-        ambient: root.ambient
-        shininess: root.shininess
-        specular: root.specular
+        ambient: "#111"
+        shininess: 1.0
+        specular: "#000"
         diffuse: TextureLoader {
             magnificationFilter: Texture.Linear
             mirrored: false
diff --git a/meshroom/ui/qml/Viewer3D/Materials/SphericalHarmonicsEffect.qml b/meshroom/ui/qml/Viewer3D/Materials/SphericalHarmonicsEffect.qml
index 1ecb3be0f3..d030a00d96 100644
--- a/meshroom/ui/qml/Viewer3D/Materials/SphericalHarmonicsEffect.qml
+++ b/meshroom/ui/qml/Viewer3D/Materials/SphericalHarmonicsEffect.qml
@@ -31,6 +31,25 @@ Effect {
                     }
                 }
             ]
+        },
+        Technique {
+            graphicsApiFilter {
+                api: GraphicsApiFilter.OpenGL
+                profile: GraphicsApiFilter.CoreProfile
+                majorVersion: 3
+                minorVersion: 2
+            }
+
+            filterKeys: [ FilterKey { name: "renderingStyle"; value: "forward" } ]
+
+            renderPasses: [
+                RenderPass {
+                    shaderProgram: ShaderProgram {
+                        vertexShaderCode:   loadSource(Qt.resolvedUrl("shaders/SphericalHarmonics_gl.vert"))
+                        fragmentShaderCode: loadSource(Qt.resolvedUrl("shaders/SphericalHarmonics_gl.frag"))
+                    }
+                }
+            ]
         }
     ]
 }
diff --git a/meshroom/ui/qml/Viewer3D/Materials/WireframeEffect.qml b/meshroom/ui/qml/Viewer3D/Materials/WireframeEffect.qml
index 0ae376e6a1..68af5a0c3b 100644
--- a/meshroom/ui/qml/Viewer3D/Materials/WireframeEffect.qml
+++ b/meshroom/ui/qml/Viewer3D/Materials/WireframeEffect.qml
@@ -29,6 +29,29 @@ Effect {
                     }
                 }
             ]
+        },
+        Technique {
+            graphicsApiFilter {
+                api: GraphicsApiFilter.OpenGL
+                profile: GraphicsApiFilter.CoreProfile
+                majorVersion: 3
+                minorVersion: 2
+            }
+
+            filterKeys: [ FilterKey { name: "renderingStyle"; value: "forward" } ]
+
+            parameters: [
+            ]
+
+            renderPasses: [
+                RenderPass {
+                    shaderProgram: ShaderProgram {
+                        vertexShaderCode:   loadSource(Qt.resolvedUrl("shaders/robustwireframe_gl.vert"))
+                        geometryShaderCode: loadSource(Qt.resolvedUrl("shaders/robustwireframe_gl.geom"))
+                        fragmentShaderCode: loadSource(Qt.resolvedUrl("shaders/robustwireframe_gl.frag"))
+                    }
+                }
+            ]
         }
     ]
 }
diff --git a/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics.frag b/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics.frag
index 2c97b3672d..f7a0c55981 100644
--- a/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics.frag
+++ b/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics.frag
@@ -1,6 +1,6 @@
 #version 450 core
 
-layout(location = 0) in vec3 normal;
+layout(location = 0) in vec3 worldPos;
 layout(location = 0) out vec4 fragColor;
 
 layout(std140, binding = 0) uniform qt3d_render_view_uniforms {
@@ -47,18 +47,19 @@ vec3 resolveSH_Opt(vec3 premulCoefficients[9], vec3 dir)
     result += premulCoefficients[5] * (dir.x * dir.z);
     result += premulCoefficients[6] * (dir.y * dir.z);
     result += premulCoefficients[7] * (dirSq.x - dirSq.y);
-    result += premulCoefficients[8] * (3 * dirSq.z - 1);
+    result += premulCoefficients[8] * (3.0 * dirSq.z - 1.0);
     return result;
 }
 
 void main()
 {
-    if(displayNormals) {
-        // Display normals mode
+    // Compute flat face normal from screen-space position derivatives
+    vec3 normal = normalize(cross(dFdx(worldPos), dFdy(worldPos)));
+
+    if (displayNormals) {
         fragColor = vec4(normal, 1.0);
     }
     else {
-        // Calculate the color from spherical harmonics coeffs
         fragColor = vec4(resolveSH_Opt(shCoeffs, normal), 1.0);
     }
 }
diff --git a/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics.vert b/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics.vert
index fea3b3d087..ad3018b93e 100644
--- a/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics.vert
+++ b/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics.vert
@@ -1,9 +1,8 @@
 #version 450 core
 
 layout(location = 0) in vec3 vertexPosition;
-layout(location = 1) in vec3 vertexNormal;
 
-layout(location = 0) out vec3 normal;
+layout(location = 0) out vec3 worldPos;
 
 layout(std140, binding = 0) uniform qt3d_render_view_uniforms {
     mat4 viewMatrix;
@@ -35,6 +34,6 @@ layout(std140, binding = 1) uniform qt3d_command_uniforms {
 
 void main()
 {
-    normal = vertexNormal;
+    worldPos = (modelMatrix * vec4(vertexPosition, 1.0)).xyz;
     gl_Position = mvp * vec4(vertexPosition, 1.0);
 }
diff --git a/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics_gl.frag b/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics_gl.frag
new file mode 100644
index 0000000000..4f261b9efc
--- /dev/null
+++ b/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics_gl.frag
@@ -0,0 +1,36 @@
+#version 330 core
+
+in vec3 worldPos;
+
+out vec4 fragColor;
+
+uniform vec3 shCoeffs[9];
+uniform bool displayNormals;
+
+vec3 resolveSH_Opt(vec3 premulCoefficients[9], vec3 dir)
+{
+    vec3 result = premulCoefficients[0] * dir.x;
+    result += premulCoefficients[1] * dir.y;
+    result += premulCoefficients[2] * dir.z;
+    result += premulCoefficients[3];
+    vec3 dirSq = dir * dir;
+    result += premulCoefficients[4] * (dir.x * dir.y);
+    result += premulCoefficients[5] * (dir.x * dir.z);
+    result += premulCoefficients[6] * (dir.y * dir.z);
+    result += premulCoefficients[7] * (dirSq.x - dirSq.y);
+    result += premulCoefficients[8] * (3.0 * dirSq.z - 1.0);
+    return result;
+}
+
+void main()
+{
+    // Compute flat face normal from screen-space position derivatives
+    vec3 normal = normalize(cross(dFdx(worldPos), dFdy(worldPos)));
+
+    if (displayNormals) {
+        fragColor = vec4(normal, 1.0);
+    }
+    else {
+        fragColor = vec4(resolveSH_Opt(shCoeffs, normal), 1.0);
+    }
+}
diff --git a/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics_gl.vert b/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics_gl.vert
new file mode 100644
index 0000000000..fadf78fd7b
--- /dev/null
+++ b/meshroom/ui/qml/Viewer3D/Materials/shaders/SphericalHarmonics_gl.vert
@@ -0,0 +1,14 @@
+#version 330 core
+
+in vec3 vertexPosition;
+
+out vec3 worldPos;
+
+uniform mat4 modelMatrix;
+uniform mat4 mvp;
+
+void main()
+{
+    worldPos = (modelMatrix * vec4(vertexPosition, 1.0)).xyz;
+    gl_Position = mvp * vec4(vertexPosition, 1.0);
+}
diff --git a/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.frag b/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.frag
new file mode 100644
index 0000000000..5132c60e85
--- /dev/null
+++ b/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.frag
@@ -0,0 +1,19 @@
+#version 330 core
+
+in vec3 barycentric;
+
+out vec4 fragColor;
+
+void main()
+{
+    float mindist = min(min(barycentric.x, barycentric.y), barycentric.z);
+
+    if (mindist < 0.05)
+    {
+        fragColor = vec4(1.0, 1.0, 1.0, 1.0);
+    }
+    else
+    {
+        discard;
+    }
+}
diff --git a/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.geom b/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.geom
new file mode 100644
index 0000000000..2a19f09ff1
--- /dev/null
+++ b/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.geom
@@ -0,0 +1,23 @@
+#version 330 core
+
+layout(triangles) in;
+layout(triangle_strip, max_vertices = 3) out;
+
+out vec3 barycentric;
+
+void main()
+{
+    barycentric = vec3(1.0, 0.0, 0.0);
+    gl_Position = gl_in[0].gl_Position;
+    EmitVertex();
+
+    barycentric = vec3(0.0, 1.0, 0.0);
+    gl_Position = gl_in[1].gl_Position;
+    EmitVertex();
+
+    barycentric = vec3(0.0, 0.0, 1.0);
+    gl_Position = gl_in[2].gl_Position;
+    EmitVertex();
+
+    EndPrimitive();
+}
diff --git a/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.vert b/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.vert
new file mode 100644
index 0000000000..bea7dd9556
--- /dev/null
+++ b/meshroom/ui/qml/Viewer3D/Materials/shaders/robustwireframe_gl.vert
@@ -0,0 +1,12 @@
+#version 330 core
+
+in vec3 vertexPosition;
+
+uniform mat4 modelMatrix;
+uniform mat4 viewMatrix;
+uniform mat4 projectionMatrix;
+
+void main()
+{
+    gl_Position = projectionMatrix * viewMatrix * modelMatrix * vec4(vertexPosition, 1.0);
+}
diff --git a/meshroom/ui/qml/Viewer3D/MediaLoader.qml b/meshroom/ui/qml/Viewer3D/MediaLoader.qml
index 4c5606eae5..e304a15518 100644
--- a/meshroom/ui/qml/Viewer3D/MediaLoader.qml
+++ b/meshroom/ui/qml/Viewer3D/MediaLoader.qml
@@ -193,6 +193,10 @@ import Utils 1.0
     // instantiate a MaterialSwitcher instead. Returns the faceCount
     function sceneLoaderPostProcess(rootEntity)
     {
+        // Ensure all geometries have normal attributes to prevent
+        // Metal RHI pipeline crashes with built-in Qt3D materials
+        Scene3DHelper.ensureNormals(rootEntity)
+
         var materials = Scene3DHelper.findChildrenByProperty(rootEntity, "diffuse")
         var entities = []
         var texCount = 0