DF File

What are DF files and how to open them

Are you having problems opening a DF file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your DF files.

What is a DF file?

DF files have multiple uses, and Lightscape Defaults is one of them. Read more about the other uses further down the page.

Lightscape Defaults

Lightscape Defaults is a parameter-settings format used by the Lightscape Visualization System to record the values of adjustable controls that affect radiosity computation and the visual display of lighting simulation results. It is intended to allow saving or loading a set of preferred or project-specific defaults, separate from the geometry, materials, or lighting definitions.

Lightscape Defaults files are written by Lightscape or by Host applications (such as 3ds Max with its Lightscape exporter) when the user saves the processing parameters that guide how a radiosity solution is computed and how that solution is displayed. Such a file can be loaded later to restore all of the saved parameter values. These settings do not include scene geometry or materials; those are held in separate formats. Lightscape Defaults files are human-readable ASCII text files, with each parameter written as a line of text.

A Lightscape Defaults file contains entries that control things such as ambient light levels; source and receiver refinement tolerances; bounds on source and receiver sizes; termination and occlusion behavior; display parameters such as brightness, contrast, filtering, speed, and length tolerances. Lines often begin with labels like "LightscapeDefaults.Ambient:" and include keywords such as RECEIVER REFINEMENT CONTROLS, SOURCE SIZE BOUNDS, OCCLUSION CONTROLS, FILTERING and CONTRAST.

The format begins with a signature in ASCII: the first line is "LightscapeDefaults.Ambient:" (in hexadecimal: 4C6967687473636170652044656661756C74730A416D6269656E74203A) at offset zero. Other header and field-labels help tools recognize the file.

How to open DF files

Important: Different programs may use files with the DF file extension for different purposes, so unless you are sure which format your DF file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested two different DF openers which you will find listed below.

Last updated: October 22, 2026

All known file formats using extension .DF

While Lightscape Defaults is a popular type of DF-file, we know of 2 different uses of the .DF file extension. Different software may use files with the same extension for different types of data.

Open Access Database

We know that one DF format is Open Access Database. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of DF files. Remember, different programs may use DF files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about DF file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.