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Prerequisites

Before refining requirements:
  1. Customer requirements exist in Requirements/CUSTOMER-REQS module
  2. System requirements specification document created with type systemRequirementsSpecification
  3. User has edit permissions on both source and target documents
  4. RTM PowerSheet view available (Whole RTM or Component RTM)

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Refinement Flow

The V-model requirements cascade follows this pattern: Each level refines the parent level into more detailed specifications. The refines link role establishes this traceability chain.

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Step 1: Open PowerSheet RTM View

  1. Navigate to Requirements space
  2. Select Whole RTM document from sidebar
  3. PowerSheet loads with four color-coded requirement levels:
    • Green = Customer Requirements
    • Purple = System Requirements
    • Teal = Subsystem Requirements
    • Blue = Design Requirements

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Step 2: Create Child Requirement

To refine a customer requirement into system requirements:
  1. Locate parent customer requirement row (green column group)
  2. Click in the System Requirements expansion column (purple header)
  3. Click ➕ Create button
  4. Fill in system requirement details:
    • ID: Auto-generated (e.g., SRS-001)
    • Description: Refined requirement text decomposing parent into system-level function
    • Classification: Select sc (Safety Critical) or cc (Conformance Critical) if inherited from parent
  5. Click Save
The new system requirement appears nested under the parent customer requirement.
One system requirement can refine multiple customer requirements. To link to additional parents, click ** Link** in the Customer Requirements column and select existing work items.

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Step 3: Decompose System to Subsystem

Repeat the pattern for subsystem decomposition:
  1. Locate parent system requirement in purple column group
  2. Click ➕ Create in Subsystem Requirements column (teal header)
  3. Fill subsystem requirement details:
    • Description: Component-specific functional requirement
    • Document: Select target subsystem specification (e.g., SUBRS-Braking)
  4. Click Save
The RTM model enforces same-subsystem constraint: design requirements can only refine subsystem requirements from matching subsystem documents. If you select wrong subsystem document during creation, traceability validation will fail.

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Step 4: Refine to Design Level

For lowest-level design requirements:
  1. Locate parent subsystem requirement in teal column group
  2. Click ➕ Create in Design Requirements column (blue header)
  3. Fill design requirement details:
    • Description: Implementation-level specification
    • Type: Select subtype (functional, interface, performance, safety)
    • Classification: Inherit SC/CC from parent or downgrade if not safety-critical
  4. Click Save

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Step 5: Verify Traceability Chain

Check complete refinement chain:
  1. Expand all column groups in PowerSheet view
  2. Verify continuous link chain from customer → system → subsystem → design
  3. Check for missing link indicators (empty cells in expansion columns)
diagram
  1. Navigate to Design space dashboard
  2. Check Design Requirements to System Requirements coverage metric
  3. If coverage < 100%, click Gap Query link to find orphaned requirements
Missing refines links break coverage calculations and ISO 26262 traceability reports. Always establish links during requirement creation rather than retrospectively — retrospective linking requires Lucene queries to find orphaned items.

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Step 6: Use Component RTM for Focused View

For subsystem-specific refinement work:
  1. Navigate to Requirements space
  2. Select Component RTM document
  3. Filter to target subsystem using document picker
  4. View shows only:
    • Subsystem requirements (left teal group)
    • Design requirements (right blue group)
    • Upward links to parent system requirements (green column)
This simplified view removes customer/system levels for faster design requirement authoring.

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Verification

You should now see:
  • ✅ Complete requirement chain in Whole RTM PowerSheet with no empty expansion cells
  • ✅ Design Requirements coverage metric on Design space dashboard shows 100% or near-100%
  • ✅ Each requirement has at least one parent link (except top-level customer requirements)
  • ✅ Classification (SC/CC) propagates from parent to child where applicable

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Common Pitfalls

Both system and subsystem requirements use Polarion type sysReq. They are distinguished only by document type constraint (systemRequirementsSpecification vs subsystemRequirementsSpecification). Always verify document type when creating refinements.
If you create design requirement in wrong document type (e.g., testsSpecification instead of designRequirementsSpecification), PowerSheet queries won’t find it. Delete and recreate in correct document.

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See Also