diff --git a/lib/dxf2lib b/lib/dxf2lib
index 9f61079..7d8f196 100644
--- a/lib/dxf2lib
+++ b/lib/dxf2lib
@@ -23,18 +23,31 @@ def get_bbox(entities):
     max_x, max_y = float('-inf'), float('-inf')
     for e in entities:
         try:
-            box = e.bbox()
-            if box:
-                (x1, y1), (x2, y2) = box.extmin, box.extmax
-                min_x, min_y = min(min_x, x1), min(min_y, y1)
-                max_x, max_y = max(max_x, x2), max(max_y, y2)
-        except Exception:
+            # Für POLYLINE-Entities: Bounding Box manuell berechnen
+            if e.dxftype() == "POLYLINE":
+                if hasattr(e, 'vertices') and len(e.vertices) > 0:
+                    for vertex in e.vertices:
+                        if hasattr(vertex, 'dxf') and hasattr(vertex.dxf, 'location'):
+                            x, y = vertex.dxf.location.x, vertex.dxf.location.y
+                            min_x, min_y = min(min_x, x), min(min_y, y)
+                            max_x, max_y = max(max_x, x), max(max_y, y)
+            else:
+                # Für andere Entity-Typen: Standard bbox() verwenden
+                box = e.bbox()
+                if box:
+                    (x1, y1), (x2, y2) = box.extmin, box.extmax
+                    min_x, min_y = min(min_x, x1), min(min_y, y1)
+                    max_x, max_y = max(max_x, x2), max(max_y, y2)
+        except Exception as err:
+            print(f"    BBox Fehler für {e.dxftype()}: {err}")
             continue
     if min_x == float('inf'):
         return None
     return Vec2((min_x + max_x) / 2, (min_y + max_y) / 2)
 
 x_offset = 0
+y_offset = 0
+blocks_in_row = 0
 
 for filename in os.listdir(INPUT_DIR):
     if not filename.lower().endswith(".dxf"):
@@ -47,6 +60,9 @@ for filename in os.listdir(INPUT_DIR):
         src_doc = ezdxf.readfile(filepath)
         src_msp = src_doc.modelspace()
         entities = list(src_msp)
+        allowed_types = {"LINE", "LWPOLYLINE", "POLYLINE", "SPLINE", "CIRCLE", "ARC"}
+        filtered_entities = [e for e in entities if e.dxftype() in allowed_types]
+        entities = filtered_entities
     except Exception as e:
         print(f"Fehler beim Lesen von {filename}: {e}")
         continue
@@ -67,9 +83,14 @@ for filename in os.listdir(INPUT_DIR):
         except Exception as err:
             print(f"Fehler in {filename}: {err}")
 
-    # Optional Vorschau
-    msp.add_blockref(name, insert=(x_offset, 0))
-    x_offset += 200  # Abstand zwischen Blöcken
+    # Platzierung in Reihen und Spalten
+    msp.add_blockref(name, insert=(x_offset, y_offset))
+    blocks_in_row += 1
+    x_offset += 250  # Abstand zwischen Blöcken in einer Reihe
+    if blocks_in_row == 20:
+        blocks_in_row = 0
+        x_offset = 0
+        y_offset -= 500  # Neue Zeile, nach unten versetzt
 
 print(f"Bibliotheks-DXF gespeichert: {OUTPUT_FILE}")
 doc.saveas(OUTPUT_FILE)