Differential Revision: https://developer.blender.org/D17109

@@ -9901,0 +9922,4 @@
+  RNA_def_property_ui_text(
+      prop,
+      "Secondary Axis",
+      "Axis that is aligned as good as possible given the alignment of the primary axis");

@@ -0,0 +38,4 @@
+  uiItemR(layout, ptr, "secondary_axis", UI_ITEM_R_EXPAND, nullptr, ICON_NONE);
+
+  if (storage.primary_axis == storage.secondary_axis) {
+    uiItemL(layout, N_("Must not be equal"), ICON_ERROR);

@@ -0,0 +70,4 @@
+
+    /* Through cancellation this will set the last axis to be the one that's neither the primary
+     * nor secondary axis. */
+    tertiary_axis_ = (0 + 1 + 2) - primary_axis - secondary_axis;

@@ -0,0 +94,4 @@
+    const float tertiary_factor = invert_tertiary ? -1.0f : 1.0f;
+
+    for (const int64_t i : mask) {
+      float3 primary = math::normalize(primaries[i]);

@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */

@@ -0,0 +124,4 @@
+      mat[primary_axis_.as_int()] = primary;
+      mat[secondary_axis_.as_int()] = secondary;
+      mat[tertiary_axis_.as_int()] = tertiary_factor * tertiary;
+      BLI_assert(math::is_orthonormal(mat));

@@ -0,0 +35,4 @@
+  uiItemR(layout, ptr, "secondary_axis", UI_ITEM_R_EXPAND, nullptr, ICON_NONE);
+
+  if (node.custom1 == node.custom2) {
+    uiItemL(layout, N_("Axes must not be equal"), ICON_ERROR);

@@ -0,0 +31,4 @@
+
+static void node_layout(uiLayout *layout, bContext * /*C*/, PointerRNA *ptr)
+{
+  const bNode &node = *static_cast<const bNode *>(ptr->data);