By Dennis Collin
When training Revit I frequently find my delegates like to be reminded about the difference between Parameter types, namely Instance Parameters and Type Parameters.
Revit parameters simply store and communicate information about elements within a model. This information can be reviewed within a project via the property palette. Instance values can be found at the top level, whereas type parameters can be accessed by editing the family type values. A change here will update the components project wide. whereas an instance change will just change the selection.
The parameter types can be defined within a Revit project file or by a loaded component. When setting parameters, users need to consider whether the parameter is ‘style’ based (Type) or needs to be a bespoke ‘unique’ value (Instance).
Typical examples of Type Parameters could be a manufacturer’s name, a product description, cost or a fire rating code. Many of these are set as out of the box pre-set definitions. Instance parameters can be used for more bespoke settings, for example a specific comment to a component, a location or unique reference like a door number or air terminal reference.
A structural column would be most likely type-based, whereas a column component representing a pilaster would be set as an instance-based component.
Elements that have length-based instance parameters will display control handles when selected in 2D views, elements with type properties can be altered via the edit type button within the property’s palette.
Consider a door. A new building would most likely use a door type with just a few standard door sizes (width would be set as a type parameter), whereas a model of an older existing building being redeveloped might have a range of older, non-standard door types that can be all kinds of sizes. In this scenario the door width might be set as an instance parameter where the door size would be considered a bespoke value.
Additionally, when setting a parameter as an Instance, users can control its behaviour by setting whether the value is aligned by a group type or can vary by group instance.
With regards to schedules both instance and type parameter definitions can be included, provided they have been setup correctly. This process I will cover in a future post. Instance parameters are ideal for bespoke values e.g. the description of unique locations like which room equipment is located in. Type parameters are also useful for information that is consistent, such as cost. Filling in a cost to a type parameter will populate all other elements of the same type with the same value. Type catalogues are useful when there are many object types like structural beams and columns.
When creating a component in Revit, a range of family types can be established potentially with style-based values such as size, materials, product descriptions and cost.
Revit’s database nature means that values can be edited in different views and will automatically update throughout. The easiest way to view bulk information on any component is via a schedule view where component references, descriptions and costs can be viewed and set.
To the untrained eye, control of Revit parameters can seem a bit daunting, however, we do provide training courses on all aspects of Revit, from beginner Essentials training to more in-depth training involving creating families and project templates where Revit parameters can be defined, edited and controlled to deliver the required outcome.
For details on upcoming training courses please visit https://training.cadline.co.uk/ or talk to one of our team on 01784 419922.