Classifying Objects

Some philosophers say that naming something is the first step toward figuring out what makes that thing different from all the other things in the world.

In a SketchUp 3D model, this idea isn’t some wishy-washy concept. When you use the Classifier to embed data into groups or or components, those groups or components become objects. When objects have names, descriptions, and so on, you can manage the details about all the classified objects.

The details that you can track and manage can represent so much more than simply what the modeled object looks like. Consider the following:

• You can count, measure, dimension, and tag objects.
• You can generate reports. When your model contains classified objects, SketchUp’s Generate Report feature enables you to output that the classification data however you need to see it.
• You can analyze your model. If you want to analyze a model for energy performance, cost, schedule or even just render a beautiful photorealistic picture from it, you need more information than exists in SketchUp’s native geometry of lines and faces. SketchUp objects can carry that information, which means you can do BIM (Building Information Modeling).
• You can export the objects into other formats or programs. When you export SketchUp objects, they can contain all kinds of higher-order representations of things. For example, if your project workflows use BIM, you can export objects classified using the IFC 2x3 schema from SketchUp into the open BIM data exchange standard, IFC. (IFC stands for Industry Foundation Classes, an open data model standard for building information.) Rendering applications can use these attributes, such as material type and light sources, to simulate a scene. SketchUp’s APIs expose all the additional data that developers need to make rich importers and exporters from just about any information modeling format.

The upshot is that if you classify your data in SketchUp, you can use BIM to create models that not only look realistic, but also contain practical data about all the objects that need to be assembled in order to keep the rain out.

Note:To use SketchUp’s Classifier tool and its related features covered in this article, you need a SketchUp Pro license.

In the sections that follow, you find out how to classify objects in SketchUp and generate a report based on that data. If you need to use classification data other than the IFC standard that SketchUp supports, learn how to import and export classifications or create your own classification data file.

Classifying objects in the SketchUp interface

Before you start classifying objects, make sure your model is ready:

• Your soon-to-be objects must start as components. Developing Components and Dynamic Components explains how to transform everyday geometry into a component.
  
  Tip: When you create a component, you can assign it a type by selection an option from the Type drop-down list in the Create Component dialog box.

• The classification system must be loaded into your template. If you create a 3D using SketchUp’s Architectural Design - Feet and Inches template, the IFC classification system is ready to go. (Otherwise, you need to import classifications.)
• You probably want to display the Classifier toolbar. IF you don’t see it, select View > Toolbars and select the Classifier checkbox

After you complete the basic housekeeping, you’re ready to start classifying objects. With the Classifier toolbar, all you have to do is click a couple of things:

1. Select your component.
2. Open the drop-down menu in the Classifier toolbar, click the arrow next to IFC 2x3 (or whatever your classification system is), and select an object type, as shown in the following figure.

The toolbar also has the Classifier tool (). Here are a few things to keep in mind as you classify objects with the Classifier tool:

• If the drop-down menu has a white background and a type, this indicates that the Classifier tool is active and clicking objects with the Classifier tool will apply the type displayed in the toolbar.
• If you click a component, the classification type is assigned to all the instances of the same component unless you hold down the Shift key as you click with the Classifier tool. Holding down the Shift key makes the component instance you click unique and applies the type data only to that component instance.
• To remove a type from an object, make Type: <undefined> active in the drop-down menu and then click an object to remove the type data. Alternatively, select the same type from the list of classification options.

If you prefer, you can select classification data from the Entity Info panel:

1. Context-click your component and select Entity Info from the menu that appears.
2. In the Entity Info panel, shown in the following figure, select a classification from the Type drop-down menu. This displays the same interface you see when using the Classifier toolbar.

You can also sample an object’s classification and apply it to another component. First make sure no geometry is selected. Then, click the Classifier tool (). Hold down the Alt key (Microsoft Windows) or Command key (Mac OS X) as you click a classified object. Release the modifier key and click another component to apply the object’s classification type.

If you need to separate a component into two different definitions, you can do that. For example, say both a floor and a ceiling are the same shape and they both need IfcSlab classifications. You don’t want to redraw the geometry, but you do want to distinguish between floors and ceilings in your information modeling. Here’s how to set up that information modeling structure with the least amount of work:

1. Copy a classified object and move it into its new position. In the example, you copy the floor and move the copy to create a ceiling.
2. Context-click the copy and select Make Unique from the menu that appears.
3. Open the Entity Info window for the copy (in this case, the ceiling).
4. Type a new definition in the Definition text box. In the following figure, you can see the Entity Info panels for the two example components; notice how they both have the same IFC type but different definitions.

Generating an attribute report

With the Generate Report feature, you can create a report that lists component attributes and download the report as a CSV file. Generating a report is a quick and easy way to see quantities, materials, and other data about items in a SketchUp model.

For example, say you have a model that contains several components (doors, columns, and slabs) and several instances of each component. You can generate a report that shows how many of each item you need and how much it will cost. The following video walks you through the process of generating a report.

Set up a template to customize report data

The Generate Report feature uses templates to determine what data appears in your report and how that data is organized. You can create several templates to reflect the different types of reports you need.

To create a template, follow these steps :

1. Select File > Generate Report. You see the templates manger.
2. Click Create New Template, and you see options to include in your template. Alternately, you can duplicate and edit the selected template to create a new template based on an existing one.
3. Select your desired filters, columns, and units for your template. For details about these options, see the following list.
4. Click Save Changes to save this template to your model so that you can use the template again. (If you need to use this template only once, you can instead click Run Report to generate a report without saving the template.)
5. Enter a title and description and then click Save to Model, as shown in the following figure. Your template is saved.

Here’s how the template options, shown in the following figure, enable you to customize your report:

• Selection: Select Entire Model, which is the default, to generate a report on your whole model. Select the Current Selection checkbox to generate a report that includes only selected entities.
• Component Nesting Levels: When the lower check box is selected, you can determine what components appear in the report based on how they’re nested in your model. The SketchUp model itself is Level 1, and any Group or Component at the root level is a Level 2 object. The entities in Level 3 are entirely dependent on how the model was created. You can see how entities are nested in a specific model by opening the Outliner panel. When the Component Nesting Levels checkbox is selected, you can enter a level or range of levels in this text box, and the report will include only entities in those levels.
• Format Columns: Use the options in this area determine what data your report includes and how it’s organized. The left column holds all the attributes you can add to your report. The icon next to each item indicates a core SketchUp attribute (). Similarly, the IFC icon () indicates an IFC attribute, and the Dynamic Component icon () indicates a dynamic component attribute. Note that the different types of attributes aren't connected, so you could have an IFC price attribute and a DC price attribute that show different prices.
  On the right, the Group By box sets how the data types you choose are grouped in a single row, and the Report Attributes box lists what attributes will appear in the report and the column order.
  To move an attribute from the left column to the right, select the attribute and click the right-pointing arrow to move it to the Report Attributes box. You can then drag any item from the Report Attributes box to the Group By box. Also, click the gear icon next to any item to select options for how an attribute is aggregated (concatenated strings, concatenated subtotals, or total sum). To customize the order of the columns in the report, use the up and down arrows or drag items to your desired location in the list.
• Units: Select what type of units your report uses. You can choose from Architectural, Decimal (in inches, feet, centimeters, meters, and so on), Engineering, or Fractional Inches. You can also set a level of precision.

Import and export a report template

When you save a report template, it's saved with your model. To share a template across models, you can export a .grt file to your hard drive by clicking the Export button in the Generate Report box and saving the file. Then in the model where you want to reuse the template, click the Import button in the Generate Report box to import that .grt file.

Alternatively, you can save your report template to a SketchUp model template, so that your report template is always available. Simply save the report template to your model and then save that model as a SketchUp template that you can use every time you start SketchUp.

Generate a report based on a template

1. Select File > Generate Report and select the template you want to use.
   Tip: If your template generates a report based on the current selection, make sure the components you want to include in your report are selected.
2. Click Run to generate the report, which then appears on-screen, as shown in the following figure.
3. (Optional) Click Download to open the Save Report dialog box. Name the file, choose where you want to save it on your hard drive, and click Save. You can then open the CSV file in a spreadsheet program or insert it as a table in LayOut.

Importing, exporting, and deleting classifications

As you work with classification files, know that SketchUp uses classification systems that are in the .skc or .xsd file formats.

To import a classification into a SketchUp model, follow these steps:

1. Select Window > Model Info.
2. In the Model Info window, select Classifications on the left.
3. In the Classifications panel, click Import. By default, a file browser opens to your user Classifications folder.
4. If you copy your .skc or .xsd file to the Classifications folder, select the file you want and click Open. Otherwise, click the Browse button to import a file from another location.

When you import a classification, that data is embedded into the SketchUp file. So if you share a SketchUp model with someone else and they open the file on their copy of SketchUp, they can reference and use the same classification.

If you receive a SketchUp file that has an embedded classification, you can export that classification to a .skc file on your computer. To do so, open the Classifications panel in the Model Info window. Select the classification from the list that appears, and click the Export button. This is helpful if you want to have a local copy of a .skc classification file to use in other SketchUp models.

When you remove a classification from your SketchUp model, you remove the type and attribute data from that SketchUp file, too. However, any classifications that exist locally on your computer stay where they are. To delete a classification from a SketchUp model, open the Model Info windows Classifications panel, select the classification, and click Delete.

Creating an SKC file

In SketchUp, the .skc file format stores the classification data that you see in the Classification tool. Each .skc file contains XML schema definition files and other files that help define additional schema metadata. All these files are zipped up in one file.

In this section, you learn about the guts of the .skc file and find steps that walk you through creating one.

For the purposes of this tutorial, you modify a sample ifcXML4.skc file to create a new SKC file with your schema data. Follow these steps to get started:

1. Click here to download the sample ifcXML4.skc file.
2. Rename the file from ifcXML4.skc to something else, like my_schema.zip.
3. Unzip my_schema.zip.

In the sections that follow, you find a introduction to each of the files in my_schema.zip. You also find details about what you can change and how to customize your classification data. After you learn about each file, you find out how to back the .zip file back into an .skc file.

doc_thumbnail.png

This image file visually represents your schema. You can replace this file with your own image file and name it however you like. (Note that SketchUp 2014 and 2015 don’t currently use this file but may do so in a future release.)

documentProperties.xml

This file is required, and you cannot change its name. However, you may want to change several fields in this file. Although SketchUp 2014 and 2015 display only your change to the title field, future releases of SketchUp may take advantage of the other fields in this file. Here’s a list of all the fields in the documentProperties.xml file and what you can and can’t change:

• The title field contains the name of your schema that appears throughout the SketchUp UI. Change it to reflect your schema’s name.
• The description field contains the schema’s description. Change it to describe your schema.
• The creator field contains the the schema creator’s name. Change it to reflect the creator of your schema.
• The revision field reflects the revision of your schema. Change it if you would like or leave this field as it is. This field must have a value.
• The created and modified fields reflect the created and modified dates of the schema. You can change these fields or leave them as they are but they can’t be blank. If you change the dates, the values must follow this format: YYYY-MM-DDThh:mm:ss. For example, sometime on January 30, 2014 looks like this: 2014-01-30T12:00:00
• The thumbnail field points to your schema’s thumbnail. If you are using a schema-specific thumbnail, change this field to reflect the name of your schema’s thumbnail.

The following figure shows the data you might want to change in the documentProperties.xml file. Don’t modify any data other than what’s highlighted here.

references.xml

This file is required to properly load the .skc file. You can’t rename it or modify anything within it.

Schemas folder

This folder holds your schema’s .xsd files. You also have the option of saving filter files in this folder. Filter files control what type data is displayed, as explained a little later in this section. Copy your .xsd files to this subfolder and delete the sample ifcXML4.xsd file.

SketchUp can process any valid .xsd file or collection of files that use the http://www.w3.org/2001/XMLSchema namespace, with the following exceptions:

• The XML Schema format allows for circular importing of .xsd files (i.e. two files referencing each other with the element). This is only supported in SketchUp 2015 and later.
• The XML Schema format allows for externally referenced .xsd files. This is only supported in SketchUp 2014 M1 and later.
• Any <xsd:list> or <xsd:choice> attributes don’t appear in the Component Options dialog box where classification attribute data is displayed. These attributes may become visible in future versions of SketchUp.

Filter files

Filter files enable you to restrict what type and attribute data is visible in the SketchUp UI by default. If an .xsd.filter file exists, a Simplify button appears in the SketchUp UI wherever type data is displayed. This Simplify button enables users to toggle between the restricted view of the schema data that you set up and the full set of data. If an .xsd file has no filter file, all types and attributes are visible.

Filter files can whitelist types and their attributes, and they can blacklist attributes:

• Whitelisting makes the types and attributes visible in the UI. When you whitelist a type, you can choose what attributes for that type appear in the Component Options dialog box.
• Blacklisted attributes are not displayed. Blacklisting an attribute affects all types that haven’t whitelisted that attribute.

To create a filter file, follow these steps:

1. Create a file with the same name as the .xsd file that you want to filter and a .filter file extension.
2. List the type names you want to make visible by default in the UI.
3. (Optional) In curly braces ({}), list any attribute data you want to make visible by default.

For example, here’s how the my_schema.xsd.filter file shown in the following figure impacts the SketchUp interface:

• A Simplify button appears for the my_schema schema.
• By default, only the IfcBeam type as well as its Name, Description, ObjectType, and Tag attributes are visible. A user can, however, click the Simplify button to toggle the display all schema data and the simplified version you set up.
• The blacklisted instanceAttributes attribute isn’t visible.

As you create your own filter files, the following tips are also good to know:

• To add comments to this file, start each line with a double forward slash (//).
• To create an attribute blacklist (instead of a whitelist), don’t add a type name to the line before the open curly brace ({).
• Save a .filter file with its .xsd counterpart. For example, if base.xsd is saved in the Schemas\base folder, you need to save base.xsd.filter in the same folder.
• The .filter file format is subject to change in future versions of SketchUp.

document.xml

This file indicates the relative path to the root .xsd file for your schema. This file is required and you can’t rename it. As shown in the following figure, change xsdFile="Schemas/ifcXML4.xsd" to point at your root .xsd file that you copied to the Schemas folder.

Repackaging your .zip file

After you customize the files, you simply have to zip them back together. Include only the necessary files — not the folder that contains all your files. If you include that folder, SketchUp can’t import your schema.

After you create the .zip file, change the extension from .zip to .skc and optionally rename the file. You are now ready to load your .skc file into SketchUp!