IFC 4.3.x development

8.5.3.9 IfcTaskTime

Change log

IFC4

added

8.5.3.9.1 Semantic definitions at the entity

IfcTaskTime captures the time-related information about a task including the different types (actual or scheduled) of starting and ending times.

All given values should be provided by the application; the IFC schema does not deal with dependencies between task time values. There is also no consistency check through where rules that guarantee a meaningful population of time values. Thus, an application is responsible to provide reasonable values and, if an application receives task times, has to make consistency checks by their own.

IfcTaskTime furthermore provides a generic mechanism to differentiate between user given time values and time values derived from user given time values and other constraints such as work calendars and assigned resources.

HISTORY  New entity in IFC4, adapted from IfcScheduleTimeControl. Differently to IfcScheduleTimeControl it is also possible to differentiate duration time measures between the two possible types; (1) work time and (2) elapsed time.

8.5.3.9.1 Attributes

#Attribute Type Description
IfcSchedulingTime
1Name OPTIONAL IfcLabel Optional name for the time definition.
2DataOrigin OPTIONAL IfcDataOriginEnum Specifies the origin of the scheduling time entity. It currently

differentiates between predicted, simulated, measured, and user defined values.
3UserDefinedDataOriginOPTIONAL IfcLabel Value of the data origin if DataOrigin attribute is USERDEFINED.
IfcTaskTime
4DurationType OPTIONAL IfcTaskDurationEnum Enables to specify the type of duration values for ScheduleDuration, ActualDuration and RemainingTime. The duration type is either work time or elapsed time.
5ScheduleDuration OPTIONAL IfcDuration 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.
6ScheduleStart OPTIONAL IfcDateTime 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.
7ScheduleFinish OPTIONAL IfcDateTime 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.
8EarlyStart OPTIONAL IfcDateTime The earliest date on which a task can be started. It is a calculated value.
9EarlyFinish OPTIONAL IfcDateTime The earliest date on which a task can be finished. It is a calculated value.
10LateStart OPTIONAL IfcDateTime The latest date on which a task can be started. It is a calculated value.
11LateFinish OPTIONAL IfcDateTime The latest date on which a task can be finished. It is a calculated value.
12FreeFloat OPTIONAL IfcDuration 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.
13TotalFloat OPTIONAL IfcDuration 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.
14IsCritical OPTIONAL IfcBoolean 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.
15StatusTime OPTIONAL IfcDateTime The date or time at which the status of the tasks within the schedule is analyzed.
16ActualDuration OPTIONAL IfcDuration 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.
17ActualStart OPTIONAL IfcDateTime 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.
18ActualFinish OPTIONAL IfcDateTime The date on which a task is actually finished.
19RemainingTime OPTIONAL IfcDuration 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.
20Completion OPTIONAL IfcPositiveRatioMeasureThe extent of completion expressed as a ratio or percentage. It is a measured value.

8.5.3.9.2 Entity inheritance

dot_inheritance IfcTaskTimeRecurring IfcTaskTimeRecurring IfcTaskTime IfcTaskTime IfcTaskTimeRecurring->IfcTaskTime IfcSchedulingTime IfcSchedulingTime IfcTaskTime->IfcSchedulingTime IfcSchedulingTime_children 4 more... IfcSchedulingTime_children->IfcSchedulingTime

8.5.3.9.3 Formal representations

ENTITY IfcTaskTime
 SUPERTYPE OF (ONEOF
	(IfcTaskTimeRecurring))
 SUBTYPE OF (IfcSchedulingTime);
	DurationType : OPTIONAL IfcTaskDurationEnum;
	ScheduleDuration : OPTIONAL IfcDuration;
	ScheduleStart : OPTIONAL IfcDateTime;
	ScheduleFinish : OPTIONAL IfcDateTime;
	EarlyStart : OPTIONAL IfcDateTime;
	EarlyFinish : OPTIONAL IfcDateTime;
	LateStart : OPTIONAL IfcDateTime;
	LateFinish : OPTIONAL IfcDateTime;
	FreeFloat : OPTIONAL IfcDuration;
	TotalFloat : OPTIONAL IfcDuration;
	IsCritical : OPTIONAL IfcBoolean;
	StatusTime : OPTIONAL IfcDateTime;
	ActualDuration : OPTIONAL IfcDuration;
	ActualStart : OPTIONAL IfcDateTime;
	ActualFinish : OPTIONAL IfcDateTime;
	RemainingTime : OPTIONAL IfcDuration;
	Completion : OPTIONAL IfcPositiveRatioMeasure;
END_ENTITY;