IfcEventTriggerTypeEnum定义了可以指定的不同类型事件触发器的范围。事件触发器类型的定义是从业务流程建模符号（BPMN）中采用的，该符号也用于定义业务流程的信息传递手册（IDM）。有关使用事件触发器类型的详细信息，请参见这些规范。
IFC4中增加的。
| Constant | Description |
|---|---|
| EVENTRULE | An event trigger that is a rule or constraint. |
| EVENTMESSAGE | An event trigger that is a message or set of information. |
| EVENTTIME | An event trigger that is at, or occurs after, a particular point in or period of time. |
| EVENTCOMPLEX | An event trigger that is a complex combination of things. |
| USERDEFINED | |
| NOTDEFINED |
EXPRESS代码
TYPE IfcEventTriggerTypeEnum = ENUMERATION OF (
EVENTRULE,
EVENTMESSAGE,
EVENTTIME,
EVENTCOMPLEX,
USERDEFINED,
NOTDEFINED);
END_TYPE;
原文：https://www.cnblogs.com/herd/p/12776749.html