scripts/startup/bl_ui/properties_data_armature.py

@@ -80,6 +80,7 @@ class DATA_PT_display(ArmatureButtonsPanel, Panel):
         sub = row.row(align=True)
         sub.active = arm.show_axes
         sub.prop(arm, "axes_position", text="Position")
+        col.prop(arm, "relation_line_position", text="Relations")
 
 
 class DATA_MT_bone_group_context_menu(Menu):

source/blender/blenloader/intern/versioning_300.cc

@@ -4027,6 +4027,13 @@ void blo_do_versions_300(FileData *fd, Library * /*lib*/, Main *bmain)
       }
     }
 
+    if (!DNA_struct_elem_find(fd->filesdna, "bArmature", "float", "relation_line_position")) {
+      /* Convert the axes draw position to its default (tip of parent bone). */
+      LISTBASE_FOREACH (bArmature *, arm, &bmain->armatures) {
+        arm->relation_line_position = 1.0;
+      }
+    }
+
     /* Keep this block, even when empty. */
   }
 }

source/blender/draw/engines/overlay/overlay_armature.cc

@@ -2052,7 +2052,7 @@ static void draw_bone_relations(ArmatureDrawContext *ctx,
                             ebone->tail,
                             ebone->parent->head,
                             ebone->parent->tail,
-                            arm->axes_position);
+                            arm->relation_line_position);
       }
     }
   }
@@ -2068,7 +2068,7 @@ static void draw_bone_relations(ArmatureDrawContext *ctx,
                               pchan->pose_tail,
                               pchan->parent->pose_head,
                               pchan->parent->pose_tail,
-                              arm->axes_position);
+                              arm->relation_line_position);
         }
       }
     }

source/blender/makesdna/DNA_armature_types.h

@@ -143,6 +143,12 @@ typedef struct bArmature {
 
   /** Relative position of the axes on the bone, from head (0.0f) to tail (1.0f). */
   float axes_position;
+
+  /** Relative position of the parent-child relation lines on the bone, from
+   * head (0.0f) to tail (1.0f). Only controls the parent side of the line; the
+   * child side is always drawn to the head of the bone. */
+  float relation_line_position;
+  char _pad2[4];
 } bArmature;
 
 /* armature->flag */

source/blender/makesrna/intern/rna_armature.c

@@ -1554,6 +1554,18 @@ static void rna_def_armature(BlenderRNA *brna)
                            "closer to the tip; decreasing moves it closer to the root");
   RNA_def_property_update(prop, 0, "rna_Armature_redraw_data");
 
+  prop = RNA_def_property(srna, "relation_line_position", PROP_FLOAT, PROP_FACTOR);
+  RNA_def_property_float_sdna(prop, NULL, "relation_line_position");
+  RNA_def_property_range(prop, 0.0, 1.0);
+  RNA_def_property_ui_range(prop, 0.0, 1.0, 10, 1);
+  RNA_def_property_ui_text(
+      prop,
+      "Relation Line Position",
+      "The start position of the relation lines from parent to child bones. Increasing the value "
+      "moves it "
+      "closer to the tip of the parent; decreasing moves it closer to the root");
+  RNA_def_property_update(prop, 0, "rna_Armature_redraw_data");
+
   prop = RNA_def_property(srna, "show_names", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "flag", ARM_DRAWNAMES);
   RNA_def_property_ui_text(prop, "Display Names", "Display bone names");