Create a Decision Tree

DTace Tutorials > Create a Decision Tree

In this tutorial we will create a worksheet that is properly formatted for a decision tree and add nodes to the tree.  We will also cover how to existing nodes.

Creating a Decision Tree Worksheet

When a new decision tree is created, a new worksheet is added to the active workbook.  DTace will set up this worksheet to start adding nodes.  Node data and settings for the tree are stored in columns A through Z of the worksheet and are protected and hidden to prevent accidental editing of data.

To create a new tree, click the New Tree button on the DTace tab of the ribbon.

The New Decision Tree form will appear.  The form has several pages of settings that can be set at the time of tree creation or you can change settings later with Tree Settings.

The only thing required at this time is the decision tree sheet name, however we will enter settings now.

The Nodes page of the form appears first.

Click Connectors on the menu at the left side of the form.  The connector settings page will appear.  This page sets the type of connectors (straight, elbow, or curved), connector routing and connection points.

Shortest routing will route each connector along the shortest path between nodes.  Ordered routing will connect nodes according to the connection point settings.

We will use curved connectors with an ordered routing.  Incoming connectors will attach to nodes on the left side of the node shape.  Outgoing connectors will attach on the right side of the node shape.

Click Layout on the menu at the left side of the form.  The layout settings will appear.  DTace will automatically arrange nodes if the auto arrange setting is on.  You also have the option to turn off auto arrange and manually move nodes around the worksheet.

We will use auto arrange so we need to set tree orientation, node spacings, and margins from the edge of the worksheet.

In a left to right orientation, the root node is at the left side of the tree and end nodes are at the right side of the tree.  In a top to bottom orientation, the root node is at the top of the tree and end nodes are at the bottom of the tree.

We will use an initial horizontal node spacing of 75 points (1/72 of an inch) and a vertical spacing of 20.  We can change this later as the tree is created to create the best looking arrangement.

The left and top margins will be set to 75 points.  The left edge of the tree will be 75 points from the left side of the visible worksheet.  The top edge of the tree will be 75 points from the top of the visible worksheet.

Now that the settings are what we want, click the Create Tree button.  A new worksheet will be created and the Add Node form will appear.

Adding Nodes

After creating the tree, the add node form appears to start adding nodes.  You can also add nodes at any time by clicking the Add Node button on the ribbon.

When the Draw Node button is clicked, the node will appear on the worksheet and the draw node form will reappear.  Now that there is at least one node on the tree, the select parent drop-down box will appear.

Each node must have a parent specified to identify connections.  In this case, the Make vs. Buy root node will be the parent of the next node we create.

After adding the remaining nodes, we get a completed tree as shown below.  Note that the node spacings had to be increased using Tree Settings to avoid overlapping text among nodes.

The node expected values are zero because the tree has not yet been rolled back.

Complete decision tree