diff --git a/src/AcDream.App/Rendering/GameWindow.cs b/src/AcDream.App/Rendering/GameWindow.cs
index 1831713..7db0c83 100644
--- a/src/AcDream.App/Rendering/GameWindow.cs
+++ b/src/AcDream.App/Rendering/GameWindow.cs
@@ -1810,16 +1810,21 @@ public sealed class GameWindow : IDisposable
                 if (setup is not null && setup.CylSpheres.Count > 0)
                 {
                     var cyl = setup.CylSpheres[0];
-                    float cylRadius = cyl.Radius > 0 ? cyl.Radius : setup.Radius;
+                    // Use the LARGER of CylSphere.Radius and Setup.Radius.
+                    // Setup.Radius is the overall bounding radius of the object.
+                    float cylRadius = MathF.Max(cyl.Radius, setup.Radius);
+                    if (cylRadius <= 0) cylRadius = 1f;
+                    float cylHeight = cyl.Height > 0 ? cyl.Height : setup.Height;
+                    if (cylHeight <= 0) cylHeight = cylRadius * 4f;
+
                     if (cylRadius > 0)
                     {
-                        // Use entity.Id directly (not partId) for the CylSphere entry.
                         _physicsEngine.ShadowObjects.Register(
                             entity.Id, entity.SourceGfxObjOrSetupId,
                             entity.Position + new System.Numerics.Vector3(cyl.Origin.X, cyl.Origin.Y, cyl.Origin.Z),
                             entity.Rotation, cylRadius,
                             origin.X, origin.Y, lb.LandblockId,
-                            AcDream.Core.Physics.ShadowCollisionType.Cylinder, cyl.Height);
+                            AcDream.Core.Physics.ShadowCollisionType.Cylinder, cylHeight);
                     }
                 }
                 else if (setup is not null && setup.Spheres.Count > 0 && partIndex == 0)