Setting field from another variable/Thymeleaf

Hello,
I am trying to set a th:field with a value from another model but I keep getting null. I found out that th:field overrides th:value and that Thymeleaf th:field generates 3 html attributes id , name an value so instead of th:field , I should use th:id , th:name and th:value. But why do I get null?

<input
 th:id="*{roomType[__${rowStat.index}__].type}"
th:name="*{roomType[__${rowStat.index}__].type}"
th:value="${viewModel.getRooms()[__${rowStat.index}__].getType()}"
 type="text"
hidden="hidden"/>