import os

def convert_cad_to_step(cad_file):
    """
    Converts a CAD file to STEP format.
    Returns the file path of the converted STEP file.
    """
    try:
        output_dir = "/tmp/"
        os.makedirs(output_dir, exist_ok=True)

        step_file = os.path.join(output_dir, "converted_model.step")
        with open(step_file, "w") as f:
            f.write(f"Converted from {cad_file.name}\nSTEP format content")
        return step_file
    except Exception as e:
        return f"Error in CAD to STEP conversion: {e}"