check if openscad is installed on system

utils.py

@@ -1,5 +1,6 @@
 #!/bin/python3
 from __future__ import annotations
+import shutil
 
 
 def ask_int(prompt: str) -> int:
@@ -39,3 +40,10 @@ def ask_yes_no(prompt: str) -> bool:
             return False
 
         print("Please enter yes or no. [y/n]")
+
+def check_openscad() -> None:
+    if shutil.which("openscad") is None:
+        raise SystemExit(
+            "OpenSCAD was not found in PATH. "
+            "Install OpenSCAD or make sure the 'openscad' command is available."
+        )