Calculate Quantities: Dimensions

Calculate Quantities: dimensions tool measures dimension quantities based on the object geometry. 

Note that there are altogether 6 different calculate quantities tools, each for specific kinds of quantities: Volumes, Surface Areas, Dimensions, Shadow Quantities, Space Surface Areas, and Openings. These can be used for calculating dimensions, perimeters, different kinds of areas, and volumes, even areas for space coverings. All six share the same basic settings described in this document.

Simplebim calculates quantities based on the geometry of objects. Because of this, it doesn’t matter which model author tool was used for creating the models or who made them. Simplebim always calculates the quantities with the same logic in a consistent way. Thus, quantities are comparable between different models and even between different projects. In other words, Simplebim calculates standardized quantities.

Quantities are calculated both for object instances and container objects. For example, a wall can either be an instance with a single geometry or it can be an assembly with several child objects, each of which has its own geometry and thus also its own quantities.

Quantities can be calculated for objects from any object class. So the wall doesn’t have to be modeled as a wall, and you can still calculate the quantity you need for it.

Learning to Use

Calculate Quantities tools are designed for professionals based on feedback from the quantity surveys during the last ten years. In professional quantity surveying there’s all sort of situations you need to manage. Because of this, there isn’t just one dimension or one area quantity in the tools. This makes the learning curve a little bit steeper. On the other hand, you can handle wide range of quantity calculation challenges with it, in a professional way.

What is cool about the tools, is that you can visualize the quantities as derived objects. This is an easy and visual way to learn the quantities and to make sure, that you are using the right quantity for your specific use case.

Settings

All six tools share a common set of configurations. Let’s first go through them, and then the additional configurations for each tool.

Objects

Select Object Class, Group, Group Category, Top Most or Part level objects. The calculation is done only to the objects included in your selection. There is a special option All, which applies the tool to all the objects in the model, but we don’t recommend using it. When doing QTO, you should know, which objects should have which quantities. Not all need all quantities. Properly managing your calculations will keep the model clean from unnecessary data. With the very big models selecting the relevant set of objects for each quantity, will also increase performance.

Operation

You can calculate quantities in three ways. 

Calculate Quantities

Calculate Quantities will measure the quantities you chose and set the values to the objects.

Derive Objects

Derive Objects will create a new derived objects based on the quantities you have chosen. In this mode the quantity values are not set.

Derive Objects with Quantities

Derive Objects with Quantities will create a new derived objects based on the quantities you have chosen. It will also measure the quantities and set the values to the derived objects. 

Property Set Name

The property set name is used, when trying to find the existing property from the model, or when the tool automatically creates properties for you. This happens, when the tool cannot find the Properties of the model.

This is not a mistake. It is actually very convenient to let the tool create the properties. This way you can skip the extra step of adding the property separately to the model. However, in order for Simplebim to export the Properties to IFC, it needs to know, which property set it belongs to. This is just how IFC works. Use the Property Set Name to define the property set. This can be basically anything. Probably some property set of your own. The one your company uses or some BIM exchange requirement has been defined.

Quantity

Here you define the quantities you want to calculate. Note that you can calculate many quantities at the same time. Check the more detailed descriptions of each quantity here.

For example if you want to calculate height. Choose ‘Height’ from the Quantity dropdown.

Please check the detailed description of each quantity below.

Property

Here you define the properties where you want to assign the results. Set for example ‘My Height’ to the Property field. The Properties are used both for the original objects and the derived objects.

If the property already exists in the model for the target objects, then the result is set to that property. If the property does not exist, then it is automatically created. This is a very convenient way to do calculations. Just make sure, that you have defined the right Property Set Name.
 

Create Derived Objects

There options are only visible if you have chosen either Derive Objects or Derive Object with Quantities operation.

This might be the coolest feature we have ever implemented in Simplebim. Create Derived Objects allows you to create new objects to the model based on the quantity. The object will have geometry, for example representing the area you calculated.

Also, the object has a reference to the original object. This reference can then be used to copy data from the original object to the newly derived object. This way the derived object can know for example the type, location, classification, system and so on it belongs to. Any data. In the case of space coverings, you can copy data both from the space object and the bounding object to the derived object.

After the derived objects have been created, they are just like any other objects in Simplebim. You can enrich their data further just like any other object’s data. And of course, they can be exported to IFC and further used and visualized in the downstream applications.

Derived Object Class

This defines the object class of the derived objects. The object class can be any basic object class from the IFC. For example Covering, Beam, Member, Building Element Proxy, and so on… This is also the object class, in which the derived object is exported to IFC. Use the name of the object class as it is written in the Objects palette.

Connection Name

Connection Name defines the Connection property name, where the references between the original and derived objects are assigned to. Make sure you use unique names, if you want to run the tool multiple times on the same model (and don’t want to update or override the existing connections). The Connection Property can be used for example in the Calculate Properties for Connected Objects tool.

Override Connections

Use this option to choose whether you want to override (checked) or update (unchecked) the Connection Property, if it already exists in the model. There are use cases for both. Maybe you want to run the tool multiple times for the same Objects with different quantities and collected all the quantities to the same Connection Property. Then you want to update/add to the Connection Property. On the other hand, if you make a mistake, you can override the Connection Property with a rerun.

Layer Name

Layer Name defines the name of the layer (layer assignment name in IFC), to which the derived object is assigned to. The layer name can be something you already have in the model, or you can enter a new one. The layer is a convenient way to find the derived object from the model after they have been created.

Create Group

Turn Create Group is on, if you want to create a group for the newly created derived objects. The groups can be either a generic groups or an IFC groups. A generic group can only be used inside Simplebim. IFC groups are exported to IFC.

This is also a convenient way to find the newly created objects from the model, but also you could feed the group to other tools to further enrich the objects. The group can be used for example as a filter for the copy function when you copy the property data from the original object to the derived one. Or in Calculate Properties tools, to further enrich the derived objects with derived properties.

Group Name

Group Name defines the group where the derived objects are assigned to. If you use a group name, which already exists in the model (under the parent group defined below), then the objects are added to this group. If the group doesn't exist yet, then a new one is created.

Parent Group

Groups can be hierarchical. Use Parent Group if you want to assign the groups under a specific parent group.

Quantities

All the dimensions are calculated based on the so-called smallest box of the object. This means that all the objects have three different dimensions.

The three main dimensions of an object can be calculated with different logic. In order to handle as many situations as possible, there are two different logics for calculating them. Both logic has three different dimensions. You can mix the dimensions calculated with the different logic but note then that in some cases, they can calculate the same thing. For example, the Height of a vertical column might be the same as its the Longest dimension. Then again Height for a pad footing would probably not be the same as the Longest dimension.

Height

The vertical dimension of the object. Note the height is not the object’s vertical dimension in its world coordinate position. The height is the most upward dimension of the object. The picture will explain this better than words.

Note that the dimensions are based on the smallest bounding box. So if for example your gable roof is modeled from one piece, then height is the vertical dimension of the whole thing.

If you need to include all three main dimensions in your quantities, use Height together with the Horizontal Longest and Horizontal Shortest.

Horizontal Longest

The larger of the object’s horizontal dimensions.

If you need to include all three main dimensions in your quantities, use Horizontal Longest together with Height and Horizontal Shortest.

Horizontal Shortest

The smaller of the object’s horizontal dimensions.

If you need to include all three main dimensions in your quantities, use Horizontal Shortest together with Height and Horizontal Longest.

Longest

The longest dimension of the object. Usually you would use this as the Length of the object. Unless you are calculating the wall lengths. Then you probably want to use the Horizontal Longest.

If you need to include all three main dimensions in your quantities, use Longest together with the Middle and Shortest.

Middle

The middle dimension of the object. In other words, not the Longest or Shortest of the three main dimensions.

If you need to include all three main dimensions in your quantities, use Middle together with the Longest and Shortest.

Shortest

The shortest dimension of the object. Usually you would use this as the width or thickness of the object.

If you need to include all three main dimensions in your quantities, use Shortest together with the Longest and Middle.

Frame

This is a derived measure for your convenience. It is calculated with the formula: 2 * Height + Shortest/Middle.