Using Templates to Account for Non-Modelled Elements

BIM and CAD models rarely contain every physical element needed for a complete carbon assessment. Fencing, reinforcement steel, drainage pipes, trench backfill, kerbs, and road markings are frequently absent from the 3D geometry, yet they contribute meaningfully to total project carbon. Templates in the open BIM Module allow you to account for these elements without reworking the original model. This article explains how templates work and provides practical examples for the most common infrastructure scenarios.

What Is a Template and When Should You Use One?

How Templates Work

Creating a Template: Step by Step

Practical Examples

What Is a Template and When Should You Use One?

In the open BIM Module, a template is a reusable composition of multiple materials assigned to a single quantity. Instead of linking one material to one modelled element, a template lets you define everything that makes up that element in proportion, so that a single extracted quantity from the model drives the carbon calculation for all components at once.

Use a template when:

• A modelled element represents a cross-section or assembly that contains several materials, for example a pavement layer package or a reinforced concrete element.
• An element type is present in the model but non-modelled components are always associated with it, for example drainage pipes alongside a road alignment, or fencing along an embankment edge.
• You are working with 2D drawings where a single area or line represents a construction package rather than a single material.
  
  

How Templates Work?

A template is defined in the Template Table within the open BIM Module. Each template has:

• A name and a base unit: the quantity unit that the model extracts for the elements this template will be applied to, for example m³, m², or linear metres.
• A list of materials, each with a material ratio per unit of the template.

When ORIS extracts the quantity of a model element, it multiplies that quantity by the material ratio of each material in the template to produce the total quantity per material.

Creating a Template: Step by Step

• In the open BIM Module, go to the Template Table tab.
• Click to create a new template. Give it a descriptive name.
• Set the template unit: this must match the quantity unit your model extracts for the elements you will apply it to.
• Add each material that forms part of the template. For each one, set the material ratio (quantity of that material per one unit of the base unit) and specify the conversion factor.
• Save the template. It is now available in the Quantity Table when mapping model elements.
• In the Quantity Table, assign the template to the relevant element rows. Make sure the quantity property selected in the model matches the unit of the template.
  
  

Practical Examples

The following examples cover the most common scenarios where templates are needed on infrastructure projects.

EXAMPLE 1 - PAVEMENT CROSS-SECTION FROM A 2D AREA

A 2D CAD drawing contains hatched areas representing different carriageway zones. Each hatched area is extracted in m². The model does not contain individual pavement layers, but the cross-section specification is known.

For every m² of hatched carriageway area extracted from the model, ORIS calculates the carbon for all five pavement layers automatically. Different hatching types (e.g. footway, cycle lane, shared surface) can have their own templates with different layer specifications.

EXAMPLE 2 - REINFORCED CONCRETE ELEMENT

A BIM model contains concrete deck elements modelled in m³. The model geometry represents the concrete volume but does not include reinforcement steel, which is always present but typically not modelled in 3D.

The steel rate of 140 kg/m³ is a typical assumption for a reinforced concrete bridge deck. This should be verified against the structural specification for the project. Different structural elements (columns, abutments, retaining walls) will have different reinforcement rates and may warrant separate templates.

EXAMPLE 3 - ROAD ALIGNMENT WITH ASSOCIATED DRAINAGE

A corridor model extracts the road alignment as a centre line in linear metres. Drainage runs parallel to the road but is not modelled as a separate element. The design specifies a standard cross-drainage package per linear metre of road.

This template captures the full material scope of a standard rural road section from a single alignment geometry element. Where the drainage specification changes along the route, separate templates can be created for each zone and applied to the corresponding segments.