Logic Tab: Create your First Rule (Overview)

The Logic tab in the Sintel Apps Designer allows you to control how a form behaves while a user is interacting with it.

Logic makes forms dynamic. It enables you to:

• Show or hide fields, sections and tabs

• Make fields required or optional

• Display validation errors

• Control workflow actions

• Control custom button visibility

• Enforce attachment or related list requirements

• Execute custom JavaScript

For example: A section can appear immediately after a choice is selected. or Approval buttons that appear when status changes.

How Logic Works

Logic is built using rules. Each rule contains three parts:

1. Conditions – When should the rule apply?
2. Steps when conditions are met – What should happen if the condition is true?
3. Steps when conditions are not met – What should happen if the condition is false?

Each rule runs independently. Multiple rules can apply to the same field or section.

Create your first Rule

Step 1: Open the Logic Tab

1. Open your form in the Sintel Apps Designer.
2. Select Logic from the top menu (Layout | Logic | Workflow | Settings).

You’ll see:

• A left panel with Conditions and Steps
• A large blank area prompting you to add a rule
• A right panel called Properties

Step 2: Add your rule

1. Click the plus (+) button in the centre area (or “Add rule”).
2. A new rule panel opens (often titled New Rule).

You will now see three sections:

• Conditions
• Steps when conditions are met
• Steps when conditions are not met

On the right, the Properties panel shows rule settings such as rule name and execution behaviour.

Step 3: Name the Rule 

In the right-hand Properties panel, give the rule a clear name.

Use a consistent naming style like:

• Show Project Details when Request Type = Project
• Make Cost Code required when Department = Finance
• Hide Approval Section unless Status = Submitted

Good names make future maintenance much easier.

Step 4: Add a Condition

In the left panel, ensure Conditions is selected.

You’ll typically see condition types such as:

• Field value check
• Form mode (New, Edit, View)
• Author
• Group membership
• Workflow status
• Related list item count
• External user
• Attachment count
• Custom JS (advanced)

Step 5: Add Steps (Actions)

Now you define what happens.

In the left panel, select Steps.
Steps are grouped by area, for example:

Form

• Form features
• Ignore validation

Section

• Set section title
• Set section description
• Set section visibility
• Set section state

Field

• Set field label
• Set field visibility
• Set field state
• Set custom error for field

Related list – Related list behaviour

Tab – Set tab visibility

Other

• Workflow action
• Custom button visibility
• Custom JS

Step 6: Drag Steps Into “When Conditions Are Met”

1. Drag the required step into Steps when conditions are met.
2. Configure it once it lands in the step area.

Common Example: Show/Hide a Field

• Drag Set field visibility
• Choose the field
• Set to Visible (when met)

Then add the opposite step in the “not met” section.

Step 7: Add Steps Into “When Conditions Are Not Met”

This is the “otherwise” behaviour.

Example:

• Drag Set field visibility
• Choose the same field
• Set to Hidden (when not met)

This avoids scenarios where a field stays visible because a user changed an earlier answer.

Step 8: Choose Rule Execution Behaviour

On the right-hand Properties panel you’ll typically see execution options such as:

• Continuous (runs as the user interacts with the form)
• Run once (runs a single time)

Recommended

• Use Continuous for visibility/required-field logic.
• Use Run once only when you are setting values or doing something that shouldn’t re-trigger repeatedly.

Step 9: Save and Test

1. Select Save
2. Open the form and test:

What’s Next?➡️ Next article: Sintel Apps Designer – Workflow Tab (Overview)
We’ll build a basic workflow with statuses and actions, then cover audiences, quorum, and notifications.