Amela
Nichiei Housing Business Transformation Story
For confidentiality, company names, project names and system images have been replaced with pseudonyms and mocks.

Without stopping the business, intothe next 10 years.

The core system handling layout, circuit design and estimates for residential solar panels SolaGrid. It handles everything from roof shape to panel layout, circuit division and estimate amount — a core tool for the solar sales and installation business.

The legacy platform — where "circuit design was slow and manual, roofs could only be checked on 2D drawings, and the logic was a person-dependent legacy C++" — wasa renewal without stopping the businessto a modern web platform. By automating everything from layout to estimate, the client gained a foundation to support its business for "the next 10 years."

View the transformation story Try the demo View overview
Estimate lead time
hours → minutes
Circuit design
manual → Auto division
Roof checking
2D drawings → 3D visualization
Logic maintenance
Person-dependent C++ → TypeScript + tests
01
Client
About the client

An industry-leading housing equipment manufacturer, “Nichiei Housing.”

Nichiei Housing is a housing equipment manufacturer that sells and installs residential solar power systems nationwide. Its core system SolaGrid at the heart of its own sales and design operations.

Proposing optimal panel layouts for both pitched and flat roofs,Sales/design staff & homeowner with a business model connecting the three parties, building a solid track record in solar sales and installation.

Business domain
Solar sales & installation
Supported roof types
Pitched & flat roofs
Core operations
Layout to estimate
Business model — 4 steps from property to estimate
02
Challenge
Business challenges they faced

4 business challenges hindering growth.

The aging legacy platform relied on the experience and manual work of veterans for design quality. Unable to keep up with a growing volume of projects or the addition of new panels and power conditioners, it had become an obstacle to business growth itself. This was not a technical problem buta management issue tied directly to proposal speed, estimate accuracy and market competitivenesshad surfaced.

① Circuit design was slow and manual
Panel island grouping, power conditioner selection and circuit division done manual manually, each project took several hours, and proposal speed had become a business bottleneck.
② Confirming the optimal panel layout was difficult (2D)
Roof checking relied on 2D drawings only, making it hard to share three-dimensional layout images of pitched and flat roofs with homeowners, so reaching agreement took time.
③ Legacy C++ was person-dependent and hard to maintain
The estimate logic was locked in a person-dependent C++ engine, with no tests, leaving it in a state where no one but the original developer could touch it.
④ Design rules were growing more complex
Each time a power conditioner or adding series design rules grew more complex, the legacy platform was slow to support new products, and the client was losing chances to differentiate from competitors.
03
Transformation
The transformation we achieved together

Without stopping the business, into “the next 10 years” across 4 areas.

As a technology partner, Amela redefined each of Nichiei Housing's business challenges as a "before → ideal" transformation. After aligning on the target vision together, the two companies co-designed 3D visualization with Three.js and automatic circuit-division logic, anda renewal without stopping operationsas top priority, re-implementing the person-dependent legacy C++ into tested TypeScript in stages.

Amela
Execution
113
Automated tests
0
Build warnings
Before → After across 4 areas
Area ①
Circuit design
BEFORE
Island grouping & power conditioner selection by hand — hours
AFTER
Automatic circuit division
Island grouping & power conditioner selection automated by logic
Area ②
Roof visualization
BEFORE
2D drawings made spatial images hard to share
AFTER
3D layout
3D visualization of roof and panel layout with Three.js
Area ③
Estimate logic
BEFORE
Person-dependent legacy C++, no tests
AFTER
TypeScript re-implementation
Maintainable with 113 tests and 0 build warnings
Area ④
Workflow
BEFORE
Layout, circuit and estimate were fragmented, causing rework
AFTER
An end-to-end workflow
Layout → circuit → estimate end-to-end via external-platform integration
Tech stack
Frontend
React Three.js TypeScript Zustand Vite
Backend
Spring Boot polygon-clipping Vitest
Infra
Docker Vite Build
04
Impact
Changes it brought to the business

Nichiei Housing's business, into the next 10 years.

After the renewal, estimate lead time was greatly shortened and circuit design was automated. The client gained a maintainable platform to support its business for "the next 10 years" and a structure that continuously creates value.

-70%
Estimate lead time
100%
Automatic circuit division
113
Automated tests
Changes by stakeholder and business impact

Each of the three stakeholders' experience changes ties directly to Nichiei Housing's business value.

🧑‍💼
STAKEHOLDER
Sales & design staff
the proposer
Before
Circuit design took hours, delaying proposals
After
Auto-generate and propose layout, circuit and estimate in minutes
Business impact
Proposal speed ↑
More closings and more projects handled
🛠️
STAKEHOLDER
Development & maintenance team
supply side
Before
Person-dependent C++, untestable and untouchable
After
Refactor safely with 113-test TypeScript
Business impact
Maintainability ↑
Faster support for new products and rules
🏠
STAKEHOLDER
Homeowner
end-customer
Before
Hard to grasp the finished image from 2D drawings
After
Check the roof and layout in 3D, then sign with confidence
Business impact
Confidence ↑
Faster consensus, higher closing rate
05
Demo
3 scenarios

Experience life after the renewal with a working demo.

Experience the main workflow from layout to estimate. Start directly from a scenario card.