3-D File

What are 3-D files and how to open them

Are you having problems opening a 3-D 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 3-D files.

What is a 3-D file?

A .3-D file is a 3-D Helicopter Simulator Scenery file.

3-D Helicopter Simulator Scenery files (.3-D) store custom environment data used by Sierra On-Line's 1987 MS-DOS video game 3-D Helicopter Simulator. These scenery files define the landscapes (terrain features, landmarks, obstacles, animated scenery) over which the helicopter flies or lands. They allow changing the game's visual setting without altering the core executable. Sierra wrote these files; the game loads them to present different scenes when the user selects a scenery via the File → Load Scenery menu.

In normal use, a player obtains scenery files either included with the game (on the main disks) or distributed later (e.g. additional scenery disks). When playing, pressing ALT-F brings up a list of available .3-D scenery files; selecting one tells the game to read its data and render the landscape accordingly. The complexity of a scenery file affects performance: more detailed scenes slow down animation.

Internally, .3-D scenery files begin with a signature of bytes including 0x3D10 at offset 0, with other fixed-offset markers such as 0x00 at offset 49 and 0xAAAAAAAAAAAAAA at offset 236. They also contain ASCII strings like "W'U'U'U'U" and "UUUUUUUU", used by the game to recognize valid scenery files.

How to open 3-D files

Important: Different programs may use files with the 3-D file extension for different purposes, so unless you are sure which format your 3-D file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 16, 2026

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