diff --git a/gnommo/models.py b/gnommo/models.py
index 31f4967..ca50416 100644
--- a/gnommo/models.py
+++ b/gnommo/models.py
@@ -26,6 +26,15 @@ class CutoutDefinition:
     height_percent: float = 0.0  # percentage (0.0-1.0) if height is -1
     width_percent: float = 0.0  # percentage (0.0-1.0) if width is -1
 
+    # New center-based model (opt-in via cx/cy in project.json). When cx_percent is
+    # set: cx/cy are the CENTER as fractions of frame width/height; width_percent and
+    # height_percent are fractions of min(W,H) (so equal values → a true square on any
+    # aspect ratio); margin_percent is a per-side inset, also a fraction of min(W,H).
+    cx_percent: Optional[float] = None
+    cy_percent: Optional[float] = None
+    margin_percent: float = 0.0
+    size_relative_to_min: bool = False
+
 
 # Backwards compatibility alias
 TalkingHeadConfig = CutoutDefinition
diff --git a/gnommo/parser.py b/gnommo/parser.py
index f79229f..f817071 100644
--- a/gnommo/parser.py
+++ b/gnommo/parser.py
@@ -223,6 +223,24 @@ def parse_project_config(project_path: Path) -> ProjectConfig:
     # override the built-ins above.
     cutouts_data = data.get("cutouts", {})
     for cutout_name, cutout_data in cutouts_data.items():
+        if "cx" in cutout_data or "cy" in cutout_data:
+            # New center-based model: cx/cy are the center (fractions of frame W/H);
+            # width/height/margin are fractions of min(W,H). width==height → square.
+            w_pct = _parse_percent(cutout_data.get("width", "100%"))
+            h_pct = _parse_percent(cutout_data.get("height", cutout_data.get("width", "100%")))
+            cutouts[cutout_name] = CutoutDefinition(
+                x=-1,
+                y=-1,
+                height=-1,
+                width=-1,
+                cx_percent=_parse_percent(cutout_data.get("cx", "50%")),
+                cy_percent=_parse_percent(cutout_data.get("cy", "50%")),
+                width_percent=w_pct,
+                height_percent=h_pct,
+                margin_percent=_parse_percent(cutout_data.get("margin", "0%")),
+                size_relative_to_min=True,
+            )
+            continue
         x, x_pct = _parse_dimension(cutout_data.get("x", 0))
         y, y_pct = _parse_dimension(cutout_data.get("y", 0))
         height, height_pct = _parse_dimension(cutout_data.get("height", 200))
@@ -290,6 +308,20 @@ def _parse_dimension(value: Any) -> tuple[int, float]:
     return 200, 0.0  # default
 
 
+def _parse_percent(value: Any, default: float = 0.0) -> float:
+    """Parse a percentage into a 0.0-based fraction. '177%' → 1.77; a bare number
+    is taken as an already-computed fraction (1.77 → 1.77). Used by the center-based
+    cutout model where values can exceed 100% (fullscreen width on 16:9)."""
+    if value is None:
+        return default
+    if isinstance(value, str):
+        v = value.strip()
+        if v.endswith("%"):
+            return float(v[:-1]) / 100.0
+        return float(v)
+    return float(value)
+
+
 def parse_slides(
     project_path: Path, config: ProjectConfig = None
 ) -> dict[str, SlideDefinition]:
diff --git a/gnommo/renderer.py b/gnommo/renderer.py
index 2868fc7..c105bea 100644
--- a/gnommo/renderer.py
+++ b/gnommo/renderer.py
@@ -675,8 +675,24 @@ def _calculate_cutout_position(
 ) -> tuple[int, int, int, int]:
     """Calculate pixel position, width, and height from cutout definition.
 
-    Returns: (x, y, width, height)
+    Returns: (x, y, width, height)  — top-left corner + size, in pixels.
     """
+    # New center-based model: cx/cy are the center as fractions of frame W/H;
+    # width/height/margin are fractions of min(W,H) so a square stays square on any
+    # aspect ratio. margin insets each side.
+    if cutout.cx_percent is not None:
+        m = min(frame_width, frame_height)
+        margin_px = cutout.margin_percent * m
+        cut_width = int(round(cutout.width_percent * m - 2 * margin_px))
+        cut_height = int(round(cutout.height_percent * m - 2 * margin_px))
+        cut_width = max(0, cut_width)
+        cut_height = max(0, cut_height)
+        center_x = cutout.cx_percent * frame_width
+        center_y = cutout.cy_percent * frame_height
+        cut_x = int(round(center_x - cut_width / 2))
+        cut_y = int(round(center_y - cut_height / 2))
+        return cut_x, cut_y, cut_width, cut_height
+
     # Calculate height
     if cutout.height >= 0:
         cut_height = cutout.height