Difference between revisions of "IFC - Industry Foundation Classes/IFC concepts/IFC cost concepts"

From Wiki.OSArch
Line 130: Line 130:
 
-->
 
-->
  
[[File:Ifc-concept-sequence-task-classification.png]]
+
[[File:Ifc-concept-cost-costitem-classification.png]]
  
 
Cost items may relate to an external classification system, where a variety of identification codes are used extensively to identify the meaning of the cost. Examples include project phase codes, CSI codes, takeoff sequence numbers, and cost accounts.
 
Cost items may relate to an external classification system, where a variety of identification codes are used extensively to identify the meaning of the cost. Examples include project phase codes, CSI codes, takeoff sequence numbers, and cost accounts.

Revision as of 02:02, 9 August 2021

The primary classes related to this concept are:

  • IfcCostSchedule
  • IfcCostItem

A cost schedule can exist

Ifc-concept-cost-costschedule.png

A cost schedule is a collection of cost items, used for a specified purpose. Typical purposes are cost plans and tenders.

Note: there is no explicit documentation which explains how a cost schedule is related back to the project or context. Therefore, in the absence of documentation, we are assuming that we declare it to the project as shown. However, this is only an assumption. There are explicit arguments against this assumption, such as that a cost schedule must be tied back to a project order. However, this evidence is not considered strong enough as it is never mentioned in the cost schedule documentation page itself.

Source: IfcProjectOrder

A cost schedule can be part of a project order

Ifc-concept-cost-projectorder.png

Project orders, such as work orders, change orders, or in particular purchase orders, may include a cost schedule. For example, a cost schedule may be used to provide an estimate of costs for a work order.

Source: IfcCostSchedule, IfcProjectOrder

A cost schedule may have approval requests

Ifc-concept-cost-costschedule-approval.png

A cost schedule may have an approval associated with it, to determine whether it is approved or not.

Source: IfcCostSchedule

A cost schedule may have a series of approvals

Ifc-concept-cost-costschedule-approval-rel.png

An approval that relates to a cost schedule may itself be broken down into sub approvals. This implies that the sub approvals (RelatedApprovals) must first be approved before the parent approval (RelatingApproval) may be approved.

Source: IfcCostSchedule

A cost schedule may have actors associated with it

Ifc-concept-cost-costschedule-actor.png

A cost schedule may describe the people who authored it, who are stakeholders, recipients, or clients.

Source: IfcCostSchedule

A cost schedule may contain cost items

Ifc-concept-cost-costschedule-costitem.png

Cost schedules can contain multiple cost items. An IfcCostItem describes a cost or financial value together with descriptive information that describes its context in a form that enables it to be used within a cost schedule. An IfcCostItem can be used to represent the cost of goods and services, the execution of works by a process, lifecycle cost and more.

Source: IfcCostSchedule

A cost item may be assigned a classification reference

Ifc-concept-cost-costitem-classification.png

Cost items may relate to an external classification system, where a variety of identification codes are used extensively to identify the meaning of the cost. Examples include project phase codes, CSI codes, takeoff sequence numbers, and cost accounts.

Source: IfcCostItem

A cost item may nest cost items

Ifc-concept-cost-costitem-nest.png

A cost item may have cost items nested within it, typically forming the hierarchy or breakdown of a cost schedule.

Source: IfcCostItem

A cost item may include arbitrary quantities

Ifc-concept-cost-costitem-costquantity.png

A cost item may specify arbitrary quantities. These quantities are not linked to model elements. If multiple quantities are included for a single cost item, each individual quantity is a component which may be summed together to derive the total quantity. For example, this cost item has two components: one with volume of 3m2, another of 2m2. The total quantity is 3 + 2 = 5. All quantities must match the same measurement type (e.g. volume, area, count, etc).

Source: IfcCostItem

A cost item may have a total monetary cost value

Ifc-concept-cost-costitem-costvalue.png

If a cost item has no cost quantities, this cost value represents the total cost of the cost item.

Source: IfcCostItem

A cost item may have a total cost derived from a unit value and quantities

Ifc-concept-cost-costitem-costvalue-unit.png

If a cost item has quantities, the cost value represents a unit cost of the cost item, which is "2" in this case. The total cost of the cost item is derived by multiplying the cost quantities and the unit cost, which is 3 x 2 = 6 in this example.

Source: IfcCostItem