diff --git a/src/app/command_driver.rs b/src/app/command_driver.rs
index 00268c3bc..11b618695 100644
--- a/src/app/command_driver.rs
+++ b/src/app/command_driver.rs
@@ -1779,7 +1779,7 @@ impl OpenCADStudio {
             } => {
                 let label = self.history_label_from_active_cmd(i, "SOLID");
                 let erase_source = erase_source.filter(|handle| {
-                    self.tabs[i].scene.document.header.delete_objects
+                    self.delete_objects != 0
                         && !self.tabs[i].scene.is_layer_locked(*handle)
                 });
                 let pending = self.begin_undo(
@@ -2534,7 +2534,7 @@ impl OpenCADStudio {
             CmdResult::EditTableCell { handle, point } => {
                 // TABLEDIT's pick: end the pick phase and hand (table, point)
                 // to the shared cell-edit launcher. A miss or a locked cell
-                // re-prompts, matching AutoCAD's select-until-valid loop.
+                // re-prompts until a valid table cell is selected.
                 use crate::modules::annotate::table_cmd::{table_cell_at, TableCellEditStart};
                 self.tabs[i].active_cmd = None;
                 self.tabs[i].snap_result = None;
@@ -3661,7 +3661,7 @@ impl OpenCADStudio {
                 taper_angle,
                 color: _,
             } => {
-                let delete_sources = self.tabs[i].scene.document.header.delete_objects;
+                let delete_sources = self.delete_objects != 0;
                 if handles.is_empty()
                     || handles
                         .iter()
@@ -3948,7 +3948,7 @@ impl OpenCADStudio {
                     self.restore_pre_cmd_tangent();
                     return Task::none();
                 }
-                let delete_sources = self.tabs[i].scene.document.header.delete_objects;
+                let delete_sources = self.delete_objects != 0;
                 use crate::command::ExtrudeMode;
                 use crate::modules::insert::solid3d_cmds::{
                     empty_revolved_surface, empty_solid3d,
@@ -4082,7 +4082,8 @@ impl OpenCADStudio {
                 use crate::command::ExtrudeMode;
                 use crate::modules::insert::solid3d_cmds::empty_solid3d;
                 use crate::scene::model::sweep_model;
-                let delete_sources = self.tabs[i].scene.document.header.delete_objects;
+                let delete_objects = self.delete_objects;
+                let delete_profiles = delete_objects != 0;
                 let path = self.tabs[i].scene.document.get_entity(path_handle).cloned();
                 let mut profiles = Vec::new();
                 let mut failed = 0usize;
@@ -4120,6 +4121,14 @@ impl OpenCADStudio {
                         failed += 1;
                         continue;
                     };
+                    let deletes_path = crate::app::delobj_deletes_auxiliary(
+                        delete_objects,
+                        surface,
+                    );
+                    if deletes_path && self.tabs[i].scene.is_layer_locked(path_handle) {
+                        failed += 1;
+                        continue;
+                    }
                     let created = if surface {
                         self.add_surface_model(sweep_model::swept_surface_entity(&record), body)
                     } else {
@@ -4132,9 +4141,12 @@ impl OpenCADStudio {
                         failed += 1;
                     } else {
                         created_handles.push(created);
-                        if delete_sources {
+                        if delete_profiles {
                             consumed.push(handle);
                         }
+                        if deletes_path {
+                            consumed.push(path_handle);
+                        }
                     }
                 }
                 if !created_handles.is_empty() {
@@ -4175,12 +4187,14 @@ impl OpenCADStudio {
                 }).collect::<Vec<_>>();
                 sources.sort_unstable_by_key(|handle| handle.value());
                 sources.dedup();
-                let delete_sources = self.tabs[i].scene.document.header.delete_objects;
-                let locked = delete_sources && sources.iter().any(|handle| self.tabs[i].scene.is_layer_locked(*handle));
+                let delete_objects = self.delete_objects;
+                let delete_sections = delete_objects != 0;
+                let section_locked = delete_sections
+                    && sources.iter().any(|handle| self.tabs[i].scene.is_layer_locked(*handle));
                 let available = sources.iter().chain(guides.iter()).copied().chain(path)
                     .filter_map(|handle| self.tabs[i].scene.document.get_entity(handle)
                         .cloned().map(|entity| (handle, entity))).collect::<Vec<_>>();
-                let result = if locked {
+                let result = if section_locked {
                     Err("LOFT: a source is on a locked layer; disable source deletion or unlock it.".to_string())
                 } else {
                     loft_command_model::record(&sections, &guides, path, &available, mode, options)
@@ -4189,6 +4203,19 @@ impl OpenCADStudio {
                 match result {
                     Ok((body, record)) => {
                         let surface = record.parameters.as_ref().is_some_and(|settings| settings.surface);
+                        let delete_auxiliary = crate::app::delobj_deletes_auxiliary(
+                            delete_objects,
+                            surface,
+                        );
+                        if delete_auxiliary
+                            && guides.iter().copied().chain(path)
+                                .any(|handle| self.tabs[i].scene.is_layer_locked(handle))
+                        {
+                            self.command_line.push_error(
+                                "LOFT: a source is on a locked layer; disable source deletion or unlock it.",
+                            );
+                            return Task::none();
+                        }
                         let dirty_before = self.tabs[i].dirty;
                         let pending = self.begin_undo(i, "LOFT", 1, true);
                         let created = if surface {
@@ -4210,7 +4237,18 @@ impl OpenCADStudio {
                             self.command_line.push_error(crate::t!("LOFT could not create a complete display. The source sections were preserved.").as_ref());
                             return Task::none();
                         } else {
-                            if delete_sources { self.tabs[i].scene.erase_entities(&sources); }
+                            let mut consumed = if delete_sections {
+                                sources.clone()
+                            } else {
+                                Vec::new()
+                            };
+                            if delete_auxiliary {
+                                consumed.extend(guides.iter().copied());
+                                consumed.extend(path);
+                            }
+                            consumed.sort_unstable_by_key(|handle| handle.value());
+                            consumed.dedup();
+                            self.tabs[i].scene.erase_entities(&consumed);
                             self.tabs[i].scene.deselect_all();
                             self.tabs[i].scene.select_entity(created, true);
                             self.tabs[i].dirty = true;
@@ -5835,6 +5873,71 @@ fn resample_widths(source: &[(f64, f64)], count: usize) -> Vec<(f64, f64)> {
         .collect()
 }
 
+#[cfg(all(test, not(target_arch = "wasm32")))]
+mod delobj_tests {
+    use super::*;
+    use acadrust::types::Vector3;
+
+    fn sweep_source_presence(value: i16, mode: crate::command::ExtrudeMode) -> (bool, bool) {
+        let mut app = OpenCADStudio::new_for_test();
+        app.automation_op(r#"{"op":"new"}"#);
+        let i = app.active_tab;
+        let mut circle = acadrust::Circle::new();
+        circle.radius = 2.0;
+        let profile = app.tabs[i]
+            .scene
+            .add_entity(acadrust::EntityType::Circle(circle));
+        let path = app.tabs[i].scene.add_entity(acadrust::EntityType::Line(
+            acadrust::Line::from_points(
+                Vector3::new(0.0, 0.0, 0.0),
+                Vector3::new(0.0, 0.0, 5.0),
+            ),
+        ));
+        app.delete_objects = value;
+
+        let _ = app.apply_cmd_result(CmdResult::SweepEntities {
+            handles: vec![profile],
+            path_handle: path,
+            mode,
+            options: crate::command::SweepOptions::default(),
+            color: [1.0; 4],
+        });
+
+        let created = app.tabs[i].scene.document.entities().any(|entity| match mode {
+            crate::command::ExtrudeMode::Solid => {
+                matches!(entity, acadrust::EntityType::Solid3D(_))
+            }
+            crate::command::ExtrudeMode::Surface => {
+                matches!(entity, acadrust::EntityType::Surface(_))
+            }
+        });
+        assert!(created, "SWEEP must produce the requested result");
+        (
+            app.tabs[i].scene.document.get_entity(profile).is_some(),
+            app.tabs[i].scene.document.get_entity(path).is_some(),
+        )
+    }
+
+    #[test]
+    fn sweep_applies_all_four_source_deletion_modes() {
+        let solid_expectations = [(true, true), (false, true), (false, false), (false, false)];
+        for (value, expected) in solid_expectations.into_iter().enumerate() {
+            assert_eq!(
+                sweep_source_presence(value as i16, crate::command::ExtrudeMode::Solid),
+                expected,
+            );
+        }
+        assert_eq!(
+            sweep_source_presence(2, crate::command::ExtrudeMode::Surface),
+            (false, false),
+        );
+        assert_eq!(
+            sweep_source_presence(3, crate::command::ExtrudeMode::Surface),
+            (false, true),
+        );
+    }
+}
+
 #[cfg(all(test, not(target_arch = "wasm32")))]
 mod thicken_tests {
     use super::*;
diff --git a/src/app/commands/draw.rs b/src/app/commands/draw.rs
index a17d1a9cb..6807abfa1 100644
--- a/src/app/commands/draw.rs
+++ b/src/app/commands/draw.rs
@@ -1113,7 +1113,8 @@ impl OpenCADStudio {
                 use acadrust::entities::Region;
                 use acadrust::types::Vector3;
                 let mut regions = Vec::new();
-                for (_, e) in self.tabs[i].scene.selected_entities().iter() {
+                let mut sources = Vec::new();
+                for (handle, e) in self.tabs[i].scene.selected_entities().iter() {
                     let supported = matches!(
                         e,
                         acadrust::EntityType::LwPolyline(pl)
@@ -1136,6 +1137,7 @@ impl OpenCADStudio {
                         );
                         region.common.layer = self.tabs[i].active_layer.clone();
                         regions.push((region, body));
+                        sources.push(*handle);
                     }
                 }
                 if regions.is_empty() {
@@ -1154,6 +1156,10 @@ impl OpenCADStudio {
                         }
                         created.push(handle);
                     }
+                    if self.delete_objects != 0 {
+                        self.tabs[i].scene.erase_entities(&sources);
+                        self.refresh_properties();
+                    }
                     self.tabs[i].dirty = true;
                     self.command_line
                         .push_output(crate::tf!("REGION: created {count} region(s).").as_ref());
@@ -1530,3 +1536,47 @@ impl OpenCADStudio {
         Some(self.finish_dispatch(cmd))
     }
 }
+
+#[cfg(test)]
+mod region_tests {
+    use crate::app::OpenCADStudio;
+
+    #[test]
+    fn region_respects_delobj_and_preserves_unconverted_sources() {
+        for delete_sources in [false, true] {
+            let mut app = OpenCADStudio::new_for_test();
+            app.automation_op(r#"{"op":"new"}"#);
+            app.automation_op(r#"{"op":"run","cmd":"CIRCLE 5,5 3"}"#);
+            app.automation_op(r#"{"op":"run","cmd":"LINE 0,0 10,10"}"#);
+            let i = app.active_tab;
+            let sources: Vec<_> = app.tabs[i].scene.document.entities()
+                .map(|entity| {
+                    (entity.common().handle, matches!(entity, acadrust::EntityType::Circle(_)))
+                })
+                .collect();
+            assert_eq!(sources.len(), 2);
+            let handles: Vec<_> = sources.iter().map(|(handle, _)| *handle).collect();
+            app.tabs[i].scene.select_entities(&handles);
+            app.delete_objects = i16::from(delete_sources);
+
+            let _ = app.dispatch_command("REGION");
+
+            for (handle, is_circle) in &sources {
+                assert_eq!(
+                    app.tabs[i].scene.document.get_entity(*handle).is_some(),
+                    !delete_sources || !is_circle,
+                );
+            }
+            let region_count = app.tabs[i].scene.document.entities()
+                .filter(|entity| matches!(entity, acadrust::EntityType::Region(_)))
+                .count();
+            assert_eq!(region_count, 1);
+
+            app.automation_op(r#"{"op":"undo"}"#);
+            for (handle, _) in &sources {
+                assert!(app.tabs[i].scene.document.get_entity(*handle).is_some());
+            }
+            assert_eq!(app.tabs[i].scene.document.entities().count(), 2);
+        }
+    }
+}
diff --git a/src/app/commands/styleprops.rs b/src/app/commands/styleprops.rs
index 939eb38fb..4efc41f80 100644
--- a/src/app/commands/styleprops.rs
+++ b/src/app/commands/styleprops.rs
@@ -1159,6 +1159,11 @@ impl OpenCADStudio {
                         "0" | "OFF" | "FALSE" => Some(false),
                         _ => None,
                     };
+                    let current_delete_objects = self.delete_objects;
+                    let requested_delete_objects = (name == "DELOBJ")
+                        .then(|| value.as_deref()?.parse::<i16>().ok())
+                        .flatten()
+                        .filter(|value| (0..=3).contains(value));
                     let outcome: Result<(String, bool), String> = {
                         let h = &mut self.tabs[i].scene.document.header;
                         match name.as_str() {
@@ -1633,15 +1638,18 @@ impl OpenCADStudio {
                                 }
                             },
                             "DELOBJ" => match &value {
-                                Some(v) => parse_bool(v)
-                                    .map(|b| {
-                                        h.delete_objects = b;
-                                        (format!("DELOBJ = {}", b as i32), true)
+                                Some(v) => v
+                                    .parse::<i16>()
+                                    .ok()
+                                    .filter(|value| (0..=3).contains(value))
+                                    .map(|value| {
+                                        (format!("DELOBJ = {value}"), true)
                                     })
-                                    .ok_or_else(|| "SETVAR: 0 or 1 required.".into()),
-                                None => {
-                                    Ok((format!("DELOBJ = {}", h.delete_objects as i32), false))
-                                }
+                                    .ok_or_else(|| "SETVAR: integer from 0 to 3 required.".into()),
+                                None => Ok((
+                                    format!("DELOBJ = {current_delete_objects}"),
+                                    false,
+                                )),
                             },
                             "PLINEGEN" => match &value {
                                 Some(v) => parse_bool(v)
@@ -2119,6 +2127,9 @@ impl OpenCADStudio {
                     };
                     match outcome {
                         Ok((msg, changed)) => {
+                            if let Some(value) = requested_delete_objects {
+                                self.delete_objects = value;
+                            }
                             if changed {
                                 if matches!(
                                     name.as_str(),
@@ -2144,6 +2155,7 @@ impl OpenCADStudio {
                                         | "GRIPHOT"
                                         | "GRIPHOVER"
                                         | "GRIPOBJLIMIT"
+                                        | "DELOBJ"
                                 ) {
                                     self.persist_settings_if_changed();
                                 } else {
@@ -3120,4 +3132,17 @@ mod tests {
         assert!(app.tabs[app.active_tab].active_cmd.is_none());
         assert_eq!(app.commandline_fade_ms, 5000);
     }
+
+    #[test]
+    fn delobj_accepts_values_zero_through_three() {
+        let mut app = fresh_app();
+
+        for value in 0..=3 {
+            let _ = app.run_command_line(&format!("SETVAR DELOBJ {value}"));
+            assert_eq!(app.delete_objects, value);
+        }
+
+        let _ = app.run_command_line("SETVAR DELOBJ 4");
+        assert_eq!(app.delete_objects, 3);
+    }
 }
diff --git a/src/app/mod.rs b/src/app/mod.rs
index 1f34f7c8a..7ecbe186a 100644
--- a/src/app/mod.rs
+++ b/src/app/mod.rs
@@ -347,6 +347,10 @@ pub(crate) enum TextEntryMode {
     FreeText,
 }
 
+pub(crate) fn delobj_deletes_auxiliary(value: i16, creates_surface: bool) -> bool {
+    value == 2 || (value == 3 && !creates_surface)
+}
+
 pub(super) struct OpenCADStudio {
     start: Instant,
     control: control::State,
@@ -566,6 +570,8 @@ pub(super) struct OpenCADStudio {
     /// `MIRRTEXT`) — the next command-line entry is its new value, empty keeps
     /// the current one.
     pending_setvar: Option<String>,
+    /// DELOBJ system variable (0–3), shared by every open drawing.
+    delete_objects: i16,
     /// Cursor is hovering over the UCS icon body — drives the hover highlight.
     ucs_icon_hover: bool,
     /// UCS icon is selected (clicked): its grips are shown and draggable.
@@ -3424,6 +3430,7 @@ impl OpenCADStudio {
             block_usage_last_persist: None,
             awaiting_vports: false,
             pending_setvar: None,
+            delete_objects: 1,
             ucs_icon_hover: false,
             ucs_icon_selected: false,
             ucs_grip_drag: None,
diff --git a/src/app/model_ops.rs b/src/app/model_ops.rs
index d767d9005..4bb5d2041 100644
--- a/src/app/model_ops.rs
+++ b/src/app/model_ops.rs
@@ -2293,7 +2293,9 @@ impl super::OpenCADStudio {
             surfaces.push(surf);
         }
         self.push_undo_snapshot(i, "CONVTOSURFACE");
-        self.tabs[i].scene.erase_entities(&handles);
+        if self.delete_objects != 0 {
+            self.tabs[i].scene.erase_entities(&handles);
+        }
         let n = surfaces.len();
         for surf in surfaces {
             self.tabs[i].scene.add_entity(EntityType::Surface(surf));
diff --git a/src/app/settings.rs b/src/app/settings.rs
index fb63859e2..bdfab8ff9 100644
--- a/src/app/settings.rs
+++ b/src/app/settings.rs
@@ -219,6 +219,10 @@ pub struct UserSettings {
     /// the current creation layer/style. Registry-style, app-level preference.
     #[serde(default = "default_dimension_continue_mode")]
     pub dimension_continue_mode: i16,
+    /// DELOBJ: source-geometry deletion policy (0–3). Registry-style,
+    /// app-level preference; first-run default is 1.
+    #[serde(default = "default_delete_objects")]
+    pub delete_objects: i16,
     /// TEXTFILL: fill TrueType glyphs (true) or draw them hollow (false).
     pub textfill: bool,
     /// When true, saving over an existing file first copies it to a sibling
@@ -275,6 +279,10 @@ fn default_clipromptlines() -> i32 {
     3
 }
 
+fn default_delete_objects() -> i16 {
+    1
+}
+
 fn default_commandline_fade_ms() -> i32 {
     3000
 }
@@ -339,6 +347,7 @@ impl Default for UserSettings {
             texteditmode: false,
             quick_dimension_snap_priority: 0,
             dimension_continue_mode: 1,
+            delete_objects: 1,
             textfill: true,
             backup_on_save: true,
             file_assoc_enabled: true,
diff --git a/src/app/update/file.rs b/src/app/update/file.rs
index 4799d1cd9..771b2603b 100644
--- a/src/app/update/file.rs
+++ b/src/app/update/file.rs
@@ -392,6 +392,7 @@ impl OpenCADStudio {
             texteditmode: self.texteditmode,
             quick_dimension_snap_priority: self.quick_dimension_snap_priority,
             dimension_continue_mode: self.dimension_continue_mode,
+            delete_objects: self.delete_objects,
             textfill: crate::scene::text::sdf_atlas::textfill(),
             backup_on_save: self.backup_on_save,
             file_assoc_enabled: self.file_assoc_enabled,
@@ -460,6 +461,7 @@ impl OpenCADStudio {
         self.texteditmode = s.texteditmode;
         self.quick_dimension_snap_priority = s.quick_dimension_snap_priority.min(1);
         self.dimension_continue_mode = s.dimension_continue_mode.clamp(0, 1);
+        self.delete_objects = s.delete_objects.clamp(0, 3);
         crate::scene::text::sdf_atlas::set_textfill(s.textfill);
         self.backup_on_save = s.backup_on_save;
         self.file_assoc_enabled = s.file_assoc_enabled;