PIComposer Community Edition

PIComposer is a STEP ISO-10303 Standard document editor powered by a highly performant EXPRESS document store. To support real-time applications, the document store utilizes its own lossless proprietary binary encoding of EXPRESS data.

Furthermore, to handle models that may not fit into device memory, PIComposer lazy loads all data on demand. EXPRESS models and their entity instances (referred to as instances) are accurately presented in its user interface as trees and directed acyclic graphs.

As a user, it is best to think of PIComposer Community Edition as Excel for BIM, with the difference being that instead of interacting with sheets, rows, columns, and cells, a user works with trees and tree nodes. By utilizing the spatial tree and entity instance detail tree, PIComposer users can interact directly with BIM models. Authoring a BIM model involves adding tree nodes and updating tree node values. Upon each user interaction, SchemaSense, PIComposer’s schema-aware intelligent agent, is active, providing user guidance and a context-sensitive set of menu commands on each node. There are three trees in PIComposer:

Most of the user’s work involves using the tools and commands of PIComposer to manipulate the above trees.

A user’s data is organized within a workspace. A workspace consists of multiple projects owned by the user. Each project is composed of many documents.

Most of the storage in PIComposer is consumed by the documents. There are various types of documents, including templates, scripts, and BIM models.

Within a BIM model, the majority of the storage is devoted to entity instances. Additionally, a model document also stores entity instance’s inverse attributes, tags, search indices, and other supplemental data.

Conceptually, models are documents in a project. However, each BIM model is a document database where documents are stored as binary buffers. These buffers store entity instances. Unlike a line in an ISO-10303 part 21 model file or an element of a typed dataset in part 26 (HDF5 binary encoding), a binary buffer typically contains a logically grouped set of entity instances. Furthermore, if an attribute of an entity instance is itself an entity type, it might be recursively composed within the owning entity instance.

That is, using part 21 and IFCPERSONANDORGANIZATION entity as an illustration, instead of storing instances as:

structually, a buffer might alternatively store IFCPERSONANDORGANIZATION as:

Storing the buffer in the latter structure has many benefits, including:

PIComposer organizes BIM model data similar to an Entity Component System (ECS).

The central elments in a BIM model are instances of a non-abstract IfcProduct subtype; these instances usually appears in the spatial tree. Each of these instance has an immutable 64-bit integer identifier and plays the entity role in a ECS system.

A component is a special type of instance that is a container of a set of IFC instances; it is composition and aggregation of a set of logically related IFC instances. These components include shapes, propertysets, local placement, and a few other types.

Currently, a component must be of the following type:

In addition to instances and components, other concrete IFC types could be instantiated into the model as free form instance and will be stored as a document. A good example of such an instance is instance of IfcOwnerHistory.

Most BIM modeling tasks in PIComposer, such as creating a model or modeling real-world objects like tables, can be easily accomplished using templates. Templates are a fundamental mechanism for users to configure, enhance, or customize PIComposer.

At its core, a template is a set of pre-programmed instructions to be executed by PIComposer, written in either Dart, C++, or JSON. PIComposer supports multiple types of templates, including:

A spatial template allows users to scaffold an IFC model during the initial creation phase. It defines the initial spatial structure of the model, such as the site, the number of IfcBuildings, and IfcBuildingStoreys. Additionally, a spatial template specifies the relative placement of each spatial element.

Spatial templates are authored using JSON.

When a spatial template is executed, a model is created with a root IfcProject and all the spatial elements specified in the JSON file. The execution also includes the relevant context information, such as the model’s unit system.

In PIComposer, distance measurements are in millimeters, and angle measurements are in radians. Property and quantity values conform to the MKS unit measure system. This convention establishes an implicit context for templates.

Instance templates serve as instance factories, simplifying the creation of instances within a model. There are four different types of instance templates (as mentioned above), and the instances created by these templates must be of the IfcShapeRepresentation type or a subtype of IfcProduct.

A simple template is an extracted representation of a component or instance within the scope of a project. It can be easily reinstantiated in any other model within the same project. Simple templates serve as a basic form of reuse in PIComposer, enabling copy and paste functionality across spaces and time. If the template represents an IfcProduct, it includes the associated shape of the instance.

A parametric template is a simple template that exposes its attriubute and composite instances and their attributes to direct user manipulation. We called the exposed attributes parametrized attributes. The parametrized attributes are configured using JSON.

A transform template is a parametric template that incorporates an associated procedure. This procedure can take a simple template as input and produce a more complex output. PIComposer includes multiple examples of parametric templates, such as a transformation that takes a BREP box as input and generates a frustum as output.

Procedural entity templates are creational procedures that instantiate instances. They are dart or C++ script with a json configuration file. The configuration file specifies the user input parameter and script input parameters. PIComposer provides several examples of procedural entity templates.

Since not all propertyset and quantityset are published within the ifc schema EXPRESS file, these missing propertyset, quantityset, plus user definded propertyset must be configured using templates so that PIComposer could properly instantiate them. These templates are json files. Many examples are provided with the PIComposer release.

The ifc4x3 schema has 130 defined types, more than 240 enum types, almost 100 select types, and more than 800 entity types. In a typical IFC office tower model, it is common to have tens of million of entity instances. To analyze and dissect this massive volume and variety of BIM data set, PIComposer provides a multitude of filters.

In a model, instances could be filtered by:

Templates could be filtered by: type and tag.

IFC models are 3d datasets. For the community edition, PIComposer 3d view is provided via integration with web-ifc-viewer from the Ifc.js project.

The source code for the integration is open source, source code is here.

To report an issue or request a feature please go to this project’s github portal: picomposer_community_edition and create an issue.

To install PIComposer, first download the installer from Microsoft App Store and follow the App store directions.

After installation, launch PIComposer and initiate the signup workflow by clicking the signup button.

Fill in your email and choose your password.

Read and accept the licensing terms.

Click the signup button.

Confirm your email to complete your signup process, and PIComposer will be ready for use.

To add a project, click the add button .

To remove a project, select it on the project list, click the minus button .

The workspace button is the home button. It routes to the workspace pane from anywhere in PIComposer.

The project button activates the project pane and displays the contents of selected project or the most recently displayed project.

The model button activates the model pane and displays the last active model content. See the [PIComposer BIM models] section for more detail about how to work with BIM models.

The preference button activates the preference page. See the [Preferenes] section for more detail.

The account button activates the account page. See the User Account section for more detail.

The help button activates the help popup menu which has two commands :

PIComposer provides user feedback using the status bar. Depending on the nature of the command, the status shows:

Each type of status can be turned on and off using preferences.

To add a model, click the button on the navigation bar. This command routes the user to the model creation page.

Click on the desired spatial template tile on the template list. Fill in the detail in the model creation dialog then click the button.

To delete a model, select it in the model list, and click the minus button.

The EXPRESS models are extremely powerful and versatile. Unfortunately, to achieve such versatility, it is extremely verbose. To name just a few instance types that must be included in a bare minuminum valid BIM model:

PIComposer uses spatial templates definition to scaffold a model. A static spatial template is a json file specifying the initial model spatial heiarchy. A example spatial template is listed below:

The root json object has two properties: * schema—​the schema name of the model, must be ifc4x3 * element—​the json object representing a spatial element in the spatial heiarchy tree. The root instance in the spatial heiarchy must be an IfcProject. The children property of this json object allows us to define the spatial tree recursively.

Each sub-object of the element has might have the following property:

When executing a spatial template, PIComposer creates the IfcProject, the necessary headers, contextual objects, and the model’s unit system. PIComposer creates two parallel heiarchy or trees:

To access the instance template listing, activate the template tab on the project pane.

Instance templates are the fundamental unit of reuse in PIComposer models. They serve as the equivalent of CATIA’s Power Copy, but with simpler creation, enhanced flexibility, and increased power. Furthermore, they can be shared and accessed by all users.

Creating instance templates is straightforward as they are derived from the basic building blocks of a model that a user has already created.

Instance templates offer customization options by adding dynamic behavior to static elements and models. This allows users to manipulate only the essential properties of a component.

They are also extensible by associating them with scripts written in Dart or C++, enabling the transformation of simple components into highly complex ones.

In addition, instance templates can be used as pure component creational procedures in Dart or C++.

A selection set is an essential component of the PIComposer user interface. Each of the three model panel tabs—spatial, placement, and filter—has its own selection set. Many commands in PIComposer are executed in the context of the current selection set. It allows users to create inter-node links, insert templates into the spatial tree, insert selected nodes into other nodes, and perform various other actions.

The spatial tree is where the model spatial structure is managed. The commands to manipulate the tree are directly available on the tree node as popup menu items. To see the context-sensitive commands on a tree node, simply right-click on it.

The commands available to the spatial tree nodes are:

To highlight its importance in the BIM model, PIComposer user interface includes the placement tree.

To access the placement tree, simply activate the placement tab.

TThe placement tree structure is immutable, meaning its structure is created during the creation of the spatial tree. When a spatial node corresponding to a placement is deleted, the placement will be automatically deleted as well.

The only available command for the placement tree is , which navigates to the placed instance associated with the IfcLocalPlacement.

While the placement tree itself is immutable, the placement node is mutable. Like all instances, its attributes can be modified using the instance detail tree.

Filters allow users to quickly search and retrieve items within the model or project. The filter tab serves as the workbench for dealing with free form instances and working with instances outside of the spatial structure framework. There are two types of filters in the model pane: instance filters and template filters.

For details about template filters, refer to the section on Working with Instance Template. In the following section, we will focus on instance filters.

The STEP ISO-10303 standard is a group of standards including an object model specification using the EXPRESS language.

An object is a collection of attributes. In PIComposer, a representation of an object is referred to as an instance—an instantiation of an entity type.

Propertyset and quantityset are packaged in a IfcRelDefinesProperties component. The preferred way to work with IfcRelDefinesProperties is using the following command on the root detail node:

Excecuting the add propertyset command activates the create propertyset dialog. Choose the desired propertyset or quantityset and click OK to complete propertyset creation.

Ifc4x3 documentation defines a large number (more than 600) of property sets and quantity sets outside of the published schema. PIComposer needs to know their content in order to instantiate them. To configure PIComposer to create these and other user-defined property sets, PIComposer uses templates.

A template is defined using a JSON file.

Layers are commonly used in CAD systems for grouping instances and controlling their visibility. In the IFC standard, the corresponding concept is embodied in the IfcPresentationLayerAssignment entity.

To setup a layer, first create a IfcPresentationLayerAssignment instance using the instance filter create command.

To add layers to an IfcShapeRepresentation component, use the add to layer command.

image::model-add-to-layer-dialog.png

In the add layer dialog, select the desired layer from the dropdown list.

To export models to ifc, click the button on the navigation bar. The exported model is saved to user’s download folder with the the file name "modelId.ifc".

To view a model in 3d view, click show the show 3d button on the navigation bar. This will kick start the export of the model to part21. When the export is completed, the web 3d viewer will be launched.

Status dispay gives feedback of success or failure to user issued commands, and for long running commands, a progress bar. The options are:

The model page’s main function is to display model structural information. PIComposer displays two structural elements of a model: the logical object spatial heiarchy and the phyical object placement heiarchy. To underscore placement’s importance, it has its own dedicate optionally display as a tree.

Users most likely spend more time on the instance tree than any other part of PIComposer’s user interface. In addition to the instance attributes, the instance tree may optionally show its related components—​shapes, propersets etc—​allowing a user to manipulate an instance and its related component centrally. The options are:

Layer filter is a object grouping mechanism useful in managing large CAD data sets and is a feature found on all main stream CAD system. PIComposer’s layer filter system is configured by the layer filter options, and these options are:

PIComposer provides model navigation through the use the spatial tree. Moreover, the spatial tree privides context switching between an instance and its components through a series of command taking advantage of the instance filter. By isolating a component in the instance filter, a component could easily be shared among instances.

One way to create an instance in the model is using the create command in the filter tab in the model page. Some entity types correspond to component entity types. Thus it is conveneint to create such entity using the component creation work flow. The follwing options activate just such a work flow:

To hide a template where there are transform of a given template, set the:

option to false.

Options in this section enable commands for authoring instance templates. These are:

Login options toggles the persistents of user login information.