Radiance

Engineering & science

Free open-source softwareEditorial overview
A CLOSER LOOK

What is Radiance?

Radiance is a suite of lighting simulation tools that calculates light behavior from scene geometry, materials, and sources. It supports daylight and illumination studies for technical users who can prepare accurate scenes and interpret physically based rendering or analysis outputs.

Lighting simulation

Daylight analysis

Material definitions

Ray-traced outputs

Is it a good fit?

Best suited to

Lighting researchers and building-performance analysts

Before you choose

Command-line workflows take practice. Material and sky assumptions strongly affect results.

Editorial assessment based on the provider’s published information. Our method

Know what you're signing up for.

The Radiance Software License 2.0 software is available without a license subscription and includes Lighting simulation and Daylight analysis. This covers the downloadable application, while optional support, third-party services, and separately licensed materials have their own terms.

No software subscription; hardware, support and any separately licensed extras are not included.

Check current official pricing

The useful parts. The trade-offs.

Why consider it

Detailed control over light modeling

Useful for quantitative lighting studies

What to keep in mind

Command-line workflows take practice

Material and sky assumptions strongly affect results

How to use it well

Model a simple room and verify geometry, surface properties, and the chosen sky or light sources before adding complexity. Compare selected values with a known case and examine sensitivity to simulation settings. Keep material inputs and scene assumptions documented, especially when presenting numerical lighting metrics alongside visually persuasive rendered images.

This is best suited to lighting researchers and building-performance analysts. Before committing a larger project, account for these trade-offs: command-line workflows take practice; material and sky assumptions strongly affect results.

A few things you might be wondering.

Is Radiance free?

The Radiance Software License 2.0 software is available without a license subscription and includes Lighting simulation and Daylight analysis. This covers the downloadable application, while optional support, third-party services, and separately licensed materials have their own terms.

Is Radiance only for producing attractive images?

No. Quantitative lighting and daylight analysis are major applications.

Do material definitions affect calculated illumination?

Yes. Surface properties are important simulation inputs.

Where can I check the latest prices?

Use the provider link on this page. Billing period, location, team size, promotions, taxes, and optional extras may affect the amount you pay.

How should I compare this tool with alternatives?

Choose tools for the same task, then compare their feature limits, platform support, and total cost for your team. The Compare button helps you keep a shortlist.

Are the user reviews moderated?

Yes. New reviews are submitted for moderation. We show published user reviews separately from the editorial overview and never assign a default user rating.

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