diff --git a/src/exporter.rs b/src/exporter.rs
index 8c191ed..616694c 100644
--- a/src/exporter.rs
+++ b/src/exporter.rs
@@ -341,11 +341,17 @@ fn export_composite_masks(
         .ok_or_else(|| "Failed to allocate secret doors mask canvas".to_string())?;
     let mut windows = Pixmap::new(g.width, g.height)
         .ok_or_else(|| "Failed to allocate windows mask canvas".to_string())?;
+    let mut start_markers = Pixmap::new(g.width, g.height)
+        .ok_or_else(|| "Failed to allocate start markers mask canvas".to_string())?;
+    let mut end_markers = Pixmap::new(g.width, g.height)
+        .ok_or_else(|| "Failed to allocate end markers mask canvas".to_string())?;
     fill_bg(&mut doors, BLACK);
     fill_bg(&mut archways, BLACK);
     fill_bg(&mut locked_doors, BLACK);
     fill_bg(&mut secret_doors, BLACK);
     fill_bg(&mut windows, BLACK);
+    fill_bg(&mut start_markers, BLACK);
+    fill_bg(&mut end_markers, BLACK);
     for door in &layout.doors {
         if door.secret {
             draw_door(&mut secret_doors, &g, door, door_w, WHITE, DoorStyle::Solid);
@@ -360,6 +366,12 @@ fn export_composite_masks(
     for window in &layout.windows {
         draw_window(&mut windows, &g, window, door_w, WHITE, DoorStyle::Solid);
     }
+    for marker in &layout.start_markers {
+        fill_rect_marker(&mut start_markers, &g, marker, WHITE);
+    }
+    for marker in &layout.end_markers {
+        fill_rect_marker(&mut end_markers, &g, marker, WHITE);
+    }
 
     let composite = render_pixmap(layout, settings)?;
     let composite_img = raster_image_from_pixmap(&composite, settings)?;
@@ -376,6 +388,8 @@ fn export_composite_masks(
     save_mask_image(folder, "locked_doors_mask", &locked_doors, settings)?;
     save_mask_image(folder, "secret_doors_mask", &secret_doors, settings)?;
     save_mask_image(folder, "windows_mask", &windows, settings)?;
+    save_mask_image(folder, "start_markers_mask", &start_markers, settings)?;
+    save_mask_image(folder, "end_markers_mask", &end_markers, settings)?;
     if settings.export_show_grid {
         let mut grid = Pixmap::new(g.width, g.height)
             .ok_or_else(|| "Failed to allocate grid mask canvas".to_string())?;
diff --git a/src/main.rs b/src/main.rs
index d2b1599..8f2ba8b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,6 +2,7 @@ mod exporter;
 mod layout;
 mod seed;
 mod settings;
+mod startend;
 mod ui;
 
 use std::collections::HashSet;
@@ -14,6 +15,7 @@ use layout::{
     DoorSettings, DungeonLayout, WindowSettings, blocked_room_cells, corridor_cells,
     shortest_path_cells,
 };
+use startend::{manual_marker_size, populate_random_markers};
 use ui::{AddTool, UiSettings, draw_side_panel};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -848,7 +850,7 @@ impl DungeonApp {
             return;
         }
 
-        let size = manual_marker_size(&self.settings, kind);
+        let size = manual_marker_size(&self.settings, matches!(kind, MarkerKind::Start));
         let origin = centered_marker_origin(cell, size, self.settings.cols, self.settings.rows);
         let marker = layout::AreaMarker { cell: origin, size };
 
@@ -2004,180 +2006,6 @@ fn centered_marker_origin(
     (cell.0.saturating_sub(half).min(max_x), cell.1.saturating_sub(half).min(max_y))
 }
 
-fn populate_random_markers(
-    mut layout: DungeonLayout,
-    settings: &UiSettings,
-) -> DungeonLayout {
-    layout.start_markers.clear();
-    layout.end_markers.clear();
-
-    if layout.rooms.is_empty() {
-        return layout;
-    }
-
-    let start_count = random_range_inclusive(
-        settings.min_start_marker_count,
-        settings.max_start_marker_count,
-        seed::derive_seed(settings.seed, 10_001),
-    );
-    let end_count = random_range_inclusive(
-        settings.min_end_marker_count,
-        settings.max_end_marker_count,
-        seed::derive_seed(settings.seed, 10_002),
-    );
-    let pair_count = start_count.min(end_count);
-
-    let mut available_start_rooms: Vec<usize> = (0..layout.rooms.len()).collect();
-    let mut available_end_rooms: Vec<usize> = (0..layout.rooms.len()).collect();
-
-    for pair_idx in 0..pair_count {
-        let (start_room_idx, end_room_idx) =
-            farthest_room_pair(&layout.rooms, &available_start_rooms, &available_end_rooms);
-        let start_room = &layout.rooms[start_room_idx];
-        let end_room = &layout.rooms[end_room_idx];
-        layout.start_markers.push(marker_in_room(
-            start_room,
-            settings.min_start_marker_size,
-            settings.max_start_marker_size,
-            seed::derive_seed(settings.seed, 11_000 + pair_idx as u64),
-        ));
-        layout.end_markers.push(marker_in_room(
-            end_room,
-            settings.min_end_marker_size,
-            settings.max_end_marker_size,
-            seed::derive_seed(settings.seed, 12_000 + pair_idx as u64),
-        ));
-        consume_room(&mut available_start_rooms, start_room_idx);
-        consume_room(&mut available_end_rooms, end_room_idx);
-    }
-
-    for idx in pair_count..start_count {
-        let room_idx = pick_room_index(
-            &available_start_rooms,
-            layout.rooms.len(),
-            seed::derive_seed(settings.seed, 13_000 + idx as u64),
-        );
-        let room = &layout.rooms[room_idx];
-        layout.start_markers.push(marker_in_room(
-            room,
-            settings.min_start_marker_size,
-            settings.max_start_marker_size,
-            seed::derive_seed(settings.seed, 14_000 + idx as u64),
-        ));
-        consume_room(&mut available_start_rooms, room_idx);
-    }
-
-    for idx in pair_count..end_count {
-        let room_idx = pick_room_index(
-            &available_end_rooms,
-            layout.rooms.len(),
-            seed::derive_seed(settings.seed, 15_000 + idx as u64),
-        );
-        let room = &layout.rooms[room_idx];
-        layout.end_markers.push(marker_in_room(
-            room,
-            settings.min_end_marker_size,
-            settings.max_end_marker_size,
-            seed::derive_seed(settings.seed, 16_000 + idx as u64),
-        ));
-        consume_room(&mut available_end_rooms, room_idx);
-    }
-
-    layout
-}
-
-fn random_range_inclusive(min: usize, max: usize, seed_value: u64) -> usize {
-    let min = min.max(1);
-    let max = max.max(min);
-    let span = max - min + 1;
-    min + (seed_value as usize % span)
-}
-
-fn manual_marker_size(settings: &UiSettings, kind: MarkerKind) -> usize {
-    match kind {
-        MarkerKind::Start => settings.min_start_marker_size.min(settings.max_start_marker_size),
-        MarkerKind::End => settings.min_end_marker_size.min(settings.max_end_marker_size),
-    }
-    .clamp(1, 10)
-}
-
-fn marker_in_room(room: &layout::Room, min_size: usize, max_size: usize, seed_value: u64) -> layout::AreaMarker {
-    let room_limit = room.width.min(room.height).max(1);
-    let min_size = min_size.clamp(1, 10).min(room_limit);
-    let max_size = max_size.clamp(min_size, 10).min(room_limit);
-    let size = random_range_inclusive(min_size, max_size, seed_value.rotate_left(7));
-    let x_span = room.width.saturating_sub(size);
-    let y_span = room.height.saturating_sub(size);
-    let x = room.x
-        + if x_span == 0 {
-            0
-        } else {
-            (seed_value as usize) % (x_span + 1)
-        };
-    let y = room.y
-        + if y_span == 0 {
-            0
-        } else {
-            (seed_value.rotate_left(19) as usize) % (y_span + 1)
-        };
-    layout::AreaMarker { cell: (x, y), size }
-}
-
-fn farthest_room_pair(
-    rooms: &[layout::Room],
-    available_start_rooms: &[usize],
-    available_end_rooms: &[usize],
-) -> (usize, usize) {
-    let start_rooms = if available_start_rooms.is_empty() {
-        (0..rooms.len()).collect::<Vec<_>>()
-    } else {
-        available_start_rooms.to_vec()
-    };
-    let end_rooms = if available_end_rooms.is_empty() {
-        (0..rooms.len()).collect::<Vec<_>>()
-    } else {
-        available_end_rooms.to_vec()
-    };
-
-    let mut best = (start_rooms[0], end_rooms[0]);
-    let mut best_dist = 0usize;
-    for &start_idx in &start_rooms {
-        for &end_idx in &end_rooms {
-            if rooms.len() > 1 && start_idx == end_idx {
-                continue;
-            }
-            let dist = room_distance_sq(&rooms[start_idx], &rooms[end_idx]);
-            if dist > best_dist {
-                best = (start_idx, end_idx);
-                best_dist = dist;
-            }
-        }
-    }
-    best
-}
-
-fn room_distance_sq(a: &layout::Room, b: &layout::Room) -> usize {
-    let ac = a.center_cell();
-    let bc = b.center_cell();
-    let dx = ac.0.abs_diff(bc.0);
-    let dy = ac.1.abs_diff(bc.1);
-    dx * dx + dy * dy
-}
-
-fn consume_room(available_rooms: &mut Vec<usize>, room_idx: usize) {
-    if let Some(pos) = available_rooms.iter().position(|&idx| idx == room_idx) {
-        available_rooms.remove(pos);
-    }
-}
-
-fn pick_room_index(available_rooms: &[usize], room_count: usize, seed_value: u64) -> usize {
-    if !available_rooms.is_empty() {
-        available_rooms[seed_value as usize % available_rooms.len()]
-    } else {
-        seed_value as usize % room_count.max(1)
-    }
-}
-
 fn draw_area_marker(
     painter: &egui::Painter,
     geometry: &GridGeometry,
diff --git a/src/startend.rs b/src/startend.rs
new file mode 100644
index 0000000..923edde
--- /dev/null
+++ b/src/startend.rs
@@ -0,0 +1,185 @@
+use crate::layout::{self, DungeonLayout};
+use crate::seed;
+use crate::ui::UiSettings;
+
+pub fn populate_random_markers(
+    mut layout: DungeonLayout,
+    settings: &UiSettings,
+) -> DungeonLayout {
+    layout.start_markers.clear();
+    layout.end_markers.clear();
+
+    if layout.rooms.is_empty() {
+        return layout;
+    }
+
+    let start_count = random_range_inclusive(
+        settings.min_start_marker_count,
+        settings.max_start_marker_count,
+        seed::derive_seed(settings.seed, 10_001),
+    );
+    let end_count = random_range_inclusive(
+        settings.min_end_marker_count,
+        settings.max_end_marker_count,
+        seed::derive_seed(settings.seed, 10_002),
+    );
+    let pair_count = start_count.min(end_count);
+
+    let mut available_start_rooms: Vec<usize> = (0..layout.rooms.len()).collect();
+    let mut available_end_rooms: Vec<usize> = (0..layout.rooms.len()).collect();
+
+    for pair_idx in 0..pair_count {
+        let (start_room_idx, end_room_idx) =
+            farthest_room_pair(&layout.rooms, &available_start_rooms, &available_end_rooms);
+        let start_room = &layout.rooms[start_room_idx];
+        let end_room = &layout.rooms[end_room_idx];
+        layout.start_markers.push(marker_in_room(
+            start_room,
+            settings.min_start_marker_size,
+            settings.max_start_marker_size,
+            seed::derive_seed(settings.seed, 11_000 + pair_idx as u64),
+        ));
+        layout.end_markers.push(marker_in_room(
+            end_room,
+            settings.min_end_marker_size,
+            settings.max_end_marker_size,
+            seed::derive_seed(settings.seed, 12_000 + pair_idx as u64),
+        ));
+        consume_room(&mut available_start_rooms, start_room_idx);
+        consume_room(&mut available_end_rooms, end_room_idx);
+    }
+
+    for idx in pair_count..start_count {
+        let room_idx = pick_room_index(
+            &available_start_rooms,
+            layout.rooms.len(),
+            seed::derive_seed(settings.seed, 13_000 + idx as u64),
+        );
+        let room = &layout.rooms[room_idx];
+        layout.start_markers.push(marker_in_room(
+            room,
+            settings.min_start_marker_size,
+            settings.max_start_marker_size,
+            seed::derive_seed(settings.seed, 14_000 + idx as u64),
+        ));
+        consume_room(&mut available_start_rooms, room_idx);
+    }
+
+    for idx in pair_count..end_count {
+        let room_idx = pick_room_index(
+            &available_end_rooms,
+            layout.rooms.len(),
+            seed::derive_seed(settings.seed, 15_000 + idx as u64),
+        );
+        let room = &layout.rooms[room_idx];
+        layout.end_markers.push(marker_in_room(
+            room,
+            settings.min_end_marker_size,
+            settings.max_end_marker_size,
+            seed::derive_seed(settings.seed, 16_000 + idx as u64),
+        ));
+        consume_room(&mut available_end_rooms, room_idx);
+    }
+
+    layout
+}
+
+pub fn manual_marker_size(settings: &UiSettings, is_start: bool) -> usize {
+    if is_start {
+        settings
+            .min_start_marker_size
+            .min(settings.max_start_marker_size)
+    } else {
+        settings.min_end_marker_size.min(settings.max_end_marker_size)
+    }
+    .clamp(1, 10)
+}
+
+fn random_range_inclusive(min: usize, max: usize, seed_value: u64) -> usize {
+    let min = min.max(1);
+    let max = max.max(min);
+    let span = max - min + 1;
+    min + (seed_value as usize % span)
+}
+
+fn marker_in_room(
+    room: &layout::Room,
+    min_size: usize,
+    max_size: usize,
+    seed_value: u64,
+) -> layout::AreaMarker {
+    let room_limit = room.width.min(room.height).max(1);
+    let min_size = min_size.clamp(1, 10).min(room_limit);
+    let max_size = max_size.clamp(min_size, 10).min(room_limit);
+    let size = random_range_inclusive(min_size, max_size, seed_value.rotate_left(7));
+    let x_span = room.width.saturating_sub(size);
+    let y_span = room.height.saturating_sub(size);
+    let x = room.x
+        + if x_span == 0 {
+            0
+        } else {
+            (seed_value as usize) % (x_span + 1)
+        };
+    let y = room.y
+        + if y_span == 0 {
+            0
+        } else {
+            (seed_value.rotate_left(19) as usize) % (y_span + 1)
+        };
+    layout::AreaMarker { cell: (x, y), size }
+}
+
+fn farthest_room_pair(
+    rooms: &[layout::Room],
+    available_start_rooms: &[usize],
+    available_end_rooms: &[usize],
+) -> (usize, usize) {
+    let start_rooms = if available_start_rooms.is_empty() {
+        (0..rooms.len()).collect::<Vec<_>>()
+    } else {
+        available_start_rooms.to_vec()
+    };
+    let end_rooms = if available_end_rooms.is_empty() {
+        (0..rooms.len()).collect::<Vec<_>>()
+    } else {
+        available_end_rooms.to_vec()
+    };
+
+    let mut best = (start_rooms[0], end_rooms[0]);
+    let mut best_dist = 0usize;
+    for &start_idx in &start_rooms {
+        for &end_idx in &end_rooms {
+            if rooms.len() > 1 && start_idx == end_idx {
+                continue;
+            }
+            let dist = room_distance_sq(&rooms[start_idx], &rooms[end_idx]);
+            if dist > best_dist {
+                best = (start_idx, end_idx);
+                best_dist = dist;
+            }
+        }
+    }
+    best
+}
+
+fn room_distance_sq(a: &layout::Room, b: &layout::Room) -> usize {
+    let ac = a.center_cell();
+    let bc = b.center_cell();
+    let dx = ac.0.abs_diff(bc.0);
+    let dy = ac.1.abs_diff(bc.1);
+    dx * dx + dy * dy
+}
+
+fn consume_room(available_rooms: &mut Vec<usize>, room_idx: usize) {
+    if let Some(pos) = available_rooms.iter().position(|&idx| idx == room_idx) {
+        available_rooms.remove(pos);
+    }
+}
+
+fn pick_room_index(available_rooms: &[usize], room_count: usize, seed_value: u64) -> usize {
+    if !available_rooms.is_empty() {
+        available_rooms[seed_value as usize % available_rooms.len()]
+    } else {
+        seed_value as usize % room_count.max(1)
+    }
+}