IfcDateTimeResource(日期资源)
IfcDateTimeResource定义了几个通用的特定于日期和时间的概念，这些概念可用于标识日历、计划和时间序列中的上下文。这些概念包括：
IfcDate、IfcTime、IfcDateTime和IfcDuration。所有给定值应在上下文中提供，并转换为公历日期上下文，并且应可由接收应用程序处理。
时间序列，是一组离散数据，每个数据都有相关的日期和时间戳，允许在时间间隔内收集的数据自然关联。时间序列数据可以使用以下实体表示：
ifcregulartimeries：时间序列数据以预定义的间隔可预测地到达，并由实体表示，以及
ifcirregulartimeries：一些或所有时间戳不遵循重复模式，不可预测的数据突发可能会到达未指定的时间点。
时间序列数据必须使用以下规则规范化：
●所有时间（通用、本地、夏时制和太阳能）均按照ISO 8601标准GMT/UTC（通用协调时间）标准化。
●规范化数据指的是前面的时间单位。
●任何滚动都由提供数据的应用程序处理。例如，当测量设备在测量时重置自身并且记录数据不包括重置前测量的数据时，发生翻转。
●只记录采集数据的时间。
●
与进程相关联的时间，如资源分配（IfcResourceTime）、任务完成时间（IfcTaskTime）、工作模式（IfcWorkTime）和计划事件（IfcEventTime）。
注意模式IfcDateTimeResource包含基于ISO 8601的定义
Types
1 IfcDate
2 IfcDateTime
3 IfcDayInMonthNumber
4 IfcDayInWeekNumber
5 IfcDuration
6 IfcMonthInYearNumber
7 IfcTime
8 IfcTimeStamp
9 IfcDataOriginEnum
10 IfcRecurrenceTypeEnum
11 IfcTaskDurationEnum (任务工期枚举)
12 IfcTimeSeriesDataTypeEnum
13 IfcTimeOrRatioSelect
Entities
1 IfcEventTime (时间时间实体)
2 IfcIrregularTimeSeries (不规则时间序列实体)
3 IfcIrregularTimeSeriesValue (不规则时间序列值实体)
4 IfcLagTime (滞后时间实体)
5 IfcRecurrencePattern ()
6 IfcRegularTimeSeries (规则时间序列实体)
7 IfcResourceTime (资源时间实体)
8 IfcSchedulingTime (调度时间实体)
9 IfcTaskTime (任务时间实体)
10 IfcTaskTimeRecurring (任务时间重复实体)
11 IfcTimePeriod (周期时间实体)
12 IfcTimeSeries ()
13 IfcTimeSeriesValue ()
14 IfcWorkTime (工作时间实体)
类型：
1 IfcDate
2 IfcDateTime
3 IfcDayInMonthNumber
4 IfcDayInWeekNumber
5 IfcDuration
6 IfcMonthInYearNumber
7 IfcTime
8 IfcTimeStamp
9 IfcDataOriginEnum
Enumeration definition
| Constant | Description |
|---|---|
| MEASURED | The origin of the time data is a measurement device. |
| PREDICTED | The time data are a prediction. |
| SIMULATED | The origin of the time data is a simulation. |
| USERDEFINED | |
| NOTDEFINED | The origin of the time data is undefined. |
10 IfcRecurrenceTypeEnum
11 IfcTaskDurationEnum
12 IfcTimeSeriesDataTypeEnum
13 IfcTimeOrRatioSelect
实体：
1 IfcEventTime
2 IfcIrregularTimeSeries
3 IfcIrregularTimeSeriesValue
4 IfcLagTime
5 IfcRecurrencePattern
6 IfcRegularTimeSeries
7 IfcResourceTime
8 IfcSchedulingTime
9 IfcTaskTime
Attribute definitions
| # | Attribute | Type | Cardinality | Description | C |
|---|---|---|---|---|---|
| 4 | DurationType | IfcTaskDurationEnum | [0:1] | Enables to specify the type of duration values for ScheduleDuration, ActualDuration and RemainingTime. The duration type is either work time or elapsed time. | X |
| 5 | ScheduleDuration | IfcDuration | [0:1] | The amount of time which is scheduled for completion of a task. The value might be measured or somehow calculated, which is defined by ScheduleDataOrigin. The value is either given as elapsed time or work time, which is defined by DurationType.
NOTE Scheduled Duration may be calculated as the time from scheduled start date to scheduled finish date. |
X |
| 6 | ScheduleStart | IfcDateTime | [0:1] | The date on which a task is scheduled to be started. The value might be measured or somehow calculated, which is defined by ScheduleDataOrigin.
NOTE The scheduled start date must be greater than or equal to the earliest start date. |
X |
| 7 | ScheduleFinish | IfcDateTime | [0:1] | The date on which a task is scheduled to be finished. The value might be measured or somehow calculated, which is defined by ScheduleDataOrigin.
NOTE The scheduled finish date must be greater than or equal to the earliest finish date. |
X |
| 8 | EarlyStart | IfcDateTime | [0:1] | The earliest date on which a task can be started. It is a calculated value. | X |
| 9 | EarlyFinish | IfcDateTime | [0:1] | The earliest date on which a task can be finished. It is a calculated value. | X |
| 10 | LateStart | IfcDateTime | [0:1] | The latest date on which a task can be started. It is a calculated value. | X |
| 11 | LateFinish | IfcDateTime | [0:1] | The latest date on which a task can be finished. It is a calculated value. | X |
| 12 | FreeFloat | IfcDuration | [0:1] | The amount of time during which the start or finish of a task may be varied without any effect on the overall programme of work. It is a calculated elapsed time value. | X |
| 13 | TotalFloat | IfcDuration | [0:1] | The difference between the duration available to carry out a task and the scheduled duration of the task. It is a calculated elapsed time value.
NOTE Total Float time may be calculated as being the difference between the scheduled duration of a task and the available duration from earliest start to latest finish. Float time may be either positive, zero or negative. Where it is zero or negative, the task becomes critical. |
X |
| 14 | IsCritical | IfcBoolean | [0:1] | A flag which identifies whether a scheduled task is a critical item within the programme.
NOTE A task becomes critical when the float time becomes zero or negative. |
X |
| 15 | StatusTime | IfcDateTime | [0:1] | The date or time at which the status of the tasks within the schedule is analyzed. | X |
| 16 | ActualDuration | IfcDuration | [0:1] | The actual duration of the task. It is a measured value. The value is either given as elapsed time or work time, which is defined by DurationType. | X |
| 17 | ActualStart | IfcDateTime | [0:1] | The date on which a task is actually started. It is a measured value.
NOTE The scheduled start date must be greater than or equal to the earliest start date. No constraint is applied to the actual start date with respect to the scheduled start date since a task may be started earlier than had originally been scheduled if circumstances allow. |
X |
| 18 | ActualFinish | IfcDateTime | [0:1] | The date on which a task is actually finished. | X |
| 19 | RemainingTime | IfcDuration | [0:1] | The amount of time remaining to complete a task. It is a predicted value. The value is either given as elapsed time or work time, which is defined by DurationType.
NOTE The time remaining in which to complete a task may be determined both for tasks which have not yet started and those which have. Remaining time for a task not yet started has the same value as the scheduled duration. For a task already started, remaining time is calculated as the difference between the scheduled finish and the point of analysis. |
X |
| 20 | Completion | IfcPositiveRatioMeasure | [0:1] | The extent of completion expressed as a ratio or percentage. It is a measured value. | X |
10 IfcTaskTimeRecurring
11 IfcTimePeriod
12 IfcTimeSeries
13 IfcTimeSeriesValue
14 IfcWorkTime
Attribute definitions
| # | Attribute | Type | Cardinality | Description | C |
|---|---|---|---|---|---|
| 4 | RecurrencePattern | IfcRecurrencePattern | [0:1] | Recurrence pattern that defines a time period, which, if given, is valid within the time period defined by IfcWorkTime.Start and IfcWorkTime.Finish. | X |
| 5 | Start | IfcDate | [0:1] | Start date of the work time (0:00), that might be further restricted by a recurrence pattern. | X |
| 6 | Finish | IfcDate | [0:1] | End date of the work time (24:00), that might be further restricted by a recurrence pattern. | X |