In the construction and architecture world, SD, DD, and CD refer to the three main phases of the design process — each representing a deeper level of detail and development in project documentation. Here’s what each term means:



🧩 1. SD – Schematic Design

Purpose: Conceptualization & overall design intent.
Stage: Early phase of the project.

What happens:

The architect or designer develops basic design ideas and overall layout.

Drawings show general arrangement, form, scale, and relationships between spaces.

Rough plans, elevations, and site layouts are created.

Basic material ideas and massing (shape and size of the building) are discussed.

Deliverables:

Concept drawings

Site plan

Preliminary floor plans and elevations

Initial cost estimate

Goal: To get client approval on the concept before moving into detailed design.

🧱 2. DD – Design Development

Purpose: Refinement & coordination of design.
Stage: Intermediate phase.

What happens:

The approved schematic design is developed with more detail and accuracy.

Architectural, structural, MEP (Mechanical, Electrical, Plumbing) systems are coordinated.

Materials, finishes, dimensions, and major components are defined.

Design intent is translated into more technical drawings.


Deliverables:

Detailed floor plans, sections, and elevations

Outline specifications

Updated cost estimate

Coordination drawings with consultants

Goal: To finalize the design before starting construction documentation.

🧾 3. CD – Construction Documents

Purpose: Technical documentation for construction.
Stage: Final design phase before tendering or construction.

What happens:

Preparation of detailed drawings and specifications used by contractors. Includes dimensions, materials, schedules, notes, and installation details. Used for bidding, permits, and actual construction.

Deliverables:

Full set of construction drawings (architectural, structural, MEP, etc.)
Specifications (materials, workmanship, codes) Final cost estimate

Goal: To provide a complete and buildable set of documents for construction.

✅ Summary Table

Phase Full Form Focus Typical Output

SD Schematic Design Concept & layout Concept plans, sketches
DD Design Development Refinement & coordination Detailed plans, outline specs
CD Construction Documents Technical detail for building Full construction drawings & specs.