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C4B vs Forma Site Design

C4B vs Autodesk Forma Site Design

Autodesk Forma Site Design, formerly Autodesk Forma, analyses sun, wind, microclimate and more on a site and massing model. C4B focuses on the site's climate itself: what it is, how it varies and how it is changing, before there is any geometry.

Last checked18 September 2026

C4B and Forma Site Design at a glance

AspectC4BForma Site Design
TypeWeb app, in the browserCloud software for site planning and analysis
PriceFree plan; paid plans from €59/month (cancellation takes effect after 12 billing cycles) or €599/year, with a 7-day free trialPaid subscription or AEC Collection; 30-day free trial
Choosing the locationSearch an address or click the map; no weather file neededA site and massing model in Forma
Weather dataNearest weather station file (Climate.OneBuilding.Org, usually TMYx) plus, in projects, site-specific reanalysis (ERA5 / ERA5-Land, CERRA, NORA3) at the exact coordinatesHistorical weather data as the base for typical conditions
Future climateSSP1-1.9 to SSP5-8.5, any year from 2025 to 2100, in projects on paid plansNot stated on the pages we reviewed
Outdoor comfortUTCI outdoor comfort, including on the Free planMicroclimate analysis of outdoor thermal comfort
Energy analysisPreliminary hourly energy balance; orientation and aspect-ratio optimization in projects on paid plansSolar energy analysis, and total carbon (embodied and operational) analysis since August 2026, first for US-hosted projects
OutputsInteractive charts; written readings on most charts in projects and a PDF report on paid plans; EPW downloads on Technical and EnterpriseInteractive analyses on the 3D model

Where Forma Site Design is strong

  • Geometry-aware analyses on real site context and massing: sun hours, daylight potential, wind, microclimate, noise and solar energy.
  • Carbon analysis alongside environmental analyses: total carbon (embodied and operational) since August 2026, first for projects hosted in the US.
  • Part of the Autodesk ecosystem, with integrations such as Revit and Rhino.
  • Rapid analyses designed for fast iteration on options.

Where C4B takes a different approach

  • Needs no model: C4B starts from an address and profiles the climate before massing begins.
  • Starts from named data sources: the nearest OneBuilding.org station file and, in projects, ERA5 / ERA5-Land, CERRA or NORA3 reanalysis at the site.
  • Covers the climate record in depth: Köppen-Geiger zones from 1901 to 2100, a temperature trend back to 1941 in projects, precipitation intensity and future climate scenarios.
  • Produces a PDF climate report for the project brief.

Forma Site Design may suit you better if

  • You are testing massing options and need geometry-specific sun, wind and noise results.
  • Your practice already works in the Autodesk ecosystem.
  • You need embodied carbon estimates at the massing stage.

C4B may suit you better if

  • You need to understand the site's climate before drawing anything.
  • You need future climate scenarios and a climate report for the brief.

See your site's climate before design begins

Pin any location and get climate, comfort and preliminary energy insight your whole team can read. Start with a 7-day free trial, or book a 30-minute demo.

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Frequently asked questions

Is Autodesk Forma the same as Forma Site Design?

Autodesk renamed its Forma site planning product to Forma Site Design in 2026, and now uses Autodesk Forma as the name of its wider industry cloud.

Does C4B need a 3D model?

No. C4B analyses the climate of a location. Some analyses use simple building parameters, such as floor area and window-to-wall ratio, but there is no modelling.

Can C4B and Forma Site Design be used together?

Yes. A C4B climate profile can frame the brief before massing, and model-based analysis can follow once there are options to test.

Sources

Information about Forma Site Design comes from its official website and documentation, checked on 18 September 2026. Products change, so check the official site for the latest details. Forma Site Design belongs to Autodesk; C4B is not affiliated with or endorsed by them.

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