Building your system models

Connecting elementary flows, products and processes through edges.

In Brightway and Activity Browser system models are defined by linking nodes (Processes, Products, and Elementary Flows) through edges. Edges represent quantitative relationships between nodes, such as a process producing an amount of product or consuming an amount of elementary flow. By connecting these nodes with edges, you can create a detailed representation of your system.

Creating nodes

To create nodes in your database, you can use the Activity Browser interface. Open your database, right click to open the context menu and click on the New process button to create a new process node. You will be prompted to enter details such as the name, location, and unit of the process.

Implementation detail

This action will create two nodes: a Process node and a Product node. The Process node represents the activity or operation, while the Product node represents the output of that process. Advanced info on backends and node types.

After creating the process, the Process details page will open. Here you can view and edit details of the process and see what it consumes and produces.

Creating edges

Edges are defined as having an input node, and output node and an amount. To create an edge you can simply drag and drop a node from Products pane onto the Process details page. This will create an edge with the dropped node as the input node, the process as the output node, and a default amount of 1. You can then edit the amount and other details of the edge in the process details page.