(Revit + Autodesk Forma)
Independent Study – M.S. Urban Design
Author: Nitiksha Mota - LinkedIn
Institution: Georgia Institute of Technology
Advisors: Prof. Brian Stone, Prof. Patrick Kastner
This repository documents a replicable workflow for evaluating how missing-middle housing infill can support climate-migration readiness while balancing environmental resilience in Atlanta neighborhoods.
The study focuses on:
- Translating zoning and overlay codes into buildable scenarios
- Testing density increases through ADUs, townhomes, and small multifamily housing
- Evaluating microclimate, energy, wind, and stormwater impacts using simulation tools
This repo is intended as a guide for future students who want to:
- Run neighborhood-scale simulations
- Compare multiple density scenarios
- Produce policy-relevant, climate-informed urban design analysis
How can existing zoning frameworks in climate-migration receiving cities like Atlanta be leveraged to increase housing supply while minimizing environmental and microclimatic impacts?
| Neighborhood | Role in Study | Development Pattern |
|---|---|---|
| Reynoldstown | Retrofit model | Built-out historic neighborhood |
| Vine City | Rebuild model | Disinvested, vacant-parcel-rich TOD area |
| Midtown | Reference model | Dense, transit-connected urban core |
- Autodesk Revit – massing + context modeling
- Autodesk Forma – climate and performance simulations
- Sun hours
- Heat stress
- Wind comfort
- Solar panel potential
- Atlanta Zoning Ordinance (R-5, SPI-19, SPI-16)
- BeltLine Overlay District regulations
- MARTA proximity and TOD guidelines
Each neighborhood is categorized by growth logic:
- Retrofit (Reynoldstown): limited vacancy, backyard infill
- Rebuild (Vine City): block-scale redevelopment
- Reference (Midtown): contextual benchmark
For each site:
- Maximum units per lot
- Height and setback limits
- Parking requirements or reductions
- ADU permissions
- Overlay intent (TOD, walkability, affordability)
This step ensures proposals are code-aligned.
Each site includes:
- Existing condition
- Proposal 1 (moderate infill)
- Proposal 2 (higher density infill)
Scenarios differ in:
- Number of units
- Roof area
- Tree canopy loss
- Ground permeability
Goal: Comparable, clean massing models.
Best practices:
- Use simple massing (avoid detailed components)
- Keep ground plane constant across scenarios
- Maintain consistent building heights
- Represent trees as simplified canopy objects
- One Revit file per scenario
- Create a Forma site using real address
- Import Revit massing
- Verify:
- Orientation
- Scale
- Terrain alignment
Purpose: Measure daylight tradeoffs caused by density.
Run conditions:
- Winter Solstice (Dec 21)
- Summer Solstice (Jul 21)
- Daytime window (e.g. 8:00–16:00)
Recorded outputs:
- % ground with ≥ 3 hours sun
- % facades with ≥ 3 hours sun
- % roofs with ≥ 3 hours sun
Interpretation focus:
- Backyard livability
- Passive solar access
- Roof usability for PV
Purpose: Evaluate thermal comfort impacts of added density.
Run condition:
- July 21, 2 PM (peak summer heat)
Metrics recorded:
- % strong heat stress
- % moderate heat stress
- Spatial concentration of heat
Key insight:
Heat stress changes were driven more by tree canopy loss than by density alone.
Purpose: Understand pedestrian-level comfort and ventilation.
Run condition:
- Prevailing east wind
Outputs:
- Comfort categories (sitting → uncomfortable)
- Wind stagnation vs channeling
- Block interior ventilation
Key tradeoff:
- Trees improve comfort but can reduce cooling airflow
Purpose: Evaluate energy resilience benefits of added density.
Metrics recorded:
- Total roof surface area
- Panel placement area
- Estimated annual energy output (kWh)
Finding:
Higher density increases total solar capacity, even if per-square-foot performance remains similar.
While Forma does not directly model runoff volume, geometry-based conclusions were drawn:
Observed impacts:
- Increased roof area → increased runoff volume
- Reduced parking helps lower impervious surface per unit
- Tree loss reduces interception and evapotranspiration
Mitigation strategies proposed:
- Mandatory rainwater harvesting
- Cool / reflective roofs
- Green roofs
- Bioswales + green streets
- Permeable paving
- Tree replacement ratios
For every analysis slide:
Findings
- Quantitative results (% or area)
- Spatial patterns
Interpretation
- Comfort impacts
- Environmental tradeoffs
- Policy relevance
- Equity implications
- ~230 new units via ADUs + small MF
- Minimal heat increase with canopy preservation
- Stormwater manageable with lot-scale mitigation
- Low displacement risk
- 196–263 new units across scenarios
- Heat stress remains similar across densities
- Significant solar + housing gains
- Stormwater impacts require district-scale solutions
For missing-middle infill:
- Rainwater harvesting on all new roofs
- Cool or green roofs
- Bioswales + curbside green infrastructure
- Permeable paving
- Tree replacement (1–2 new trees per removal)
- Quantitative stormwater modeling (SWMM / SCS-CN)
- Canopy sensitivity testing
- Neighborhood-to-neighborhood comparison toolkit
- Policy scenario testing (density bonuses tied to resilience)
This repository is based on the Independent Study submission:
“Climate-Migration Readiness in Atlanta: Housing + Resilient Infrastructure”
Georgia Institute of Technology, 2025
If you are continuing this work:
- Keep simulation settings constant
- Always compare Existing vs Proposal
- Pair density increases with required mitigation
- Use simulations to support policy arguments, not just visuals