Standard File formats in Revit

Revit Native Formats:

.rvt

The rvt file extension is primarily associated with Revit Architecture, a Building Information Modeling (BIM) software developed by Autodesk.

The rvt file contains Revit project created and saved in the program, including building design, sections, floor plans and other data used to render 3D view.

.rfa

The rfa file extension is associated with Autodesk Revit Architecture. Revit model is based on a compilation of items called families.

There are two types of families: system families and hosted families.

A system family can only be found within a Revit model and cannot be stored in a separate location. A hosted family is inserted similar to a block (or cell) and is stored in an external directory.

The rfa file contains finished Revit family data.

.rte

The rte file extension is associated with Revit Architecture, a building information modeling software developed by Autodesk.

The rte file contains templates used for quickly creation of projects with the same settings. These Revit projects are stored in rvt format.

.rft

File extension rft is most likely best known for its use in Revit Architecture, architecture design, and modeling software from Autodesk.

A .rtf file is another type of template, only this one pertains to a family template. Revit model is based on a compilation of items called families. A template is used to specifying future family files.

CAD Formats:

.dgn

The dgn file extension is used by MicroStation, a CAD program developed and marketed by Bentley Systems.

The dgn file contains design created and used within the program. It is one of the main MicroStation formats.

.dwf

The dwf file extension is associated with Design (Drawing) Web format used by AutoCAD and Inventor.

Design Web Format (DWF) is a secure file format developed by Autodesk for the efficient distribution and communication of rich design data to anyone who needs to view, review, or print design files. Because DWF files are highly compressed, they are smaller and faster to transmit than design files, without the overhead associated with complex CAD drawings (or the management of external links and dependencies).

With DWF functionality, publishers of design data can limit the specific design data and plot styles to only what they want recipients to see and can publish multisheet drawing sets from multiple AutoCAD drawings in a single DWF file. They can also publish 3D models from most Autodesk design applications.

.dwfx

The dwfx file extension is associated with the Design Web Format developed by Autodesk and used by its various apps, like AutoCAD and Inventor.

It is used for distribution of CAD design data and allows users to view, review and print design files. It is based on standardized formats like ZLIB, XML, ZIP, PNG. Source codes and specifications of DWF format are available for free.

DWFX format is very similar to Microsoft XPS (Open XML Paper Specification) you can rename dwfx extension to XPS and try to view it in XPS document viewer.

.dwg

The dwg file extension is associated with AutoCAD, a CAD software for Microsoft Windows and Apple Mac developed by Autodesk, Inc..

The dwg (drawing) file format is a proprietary format used to store two or three dimensional data with any other metadata.

DWG file format was developed in the late 1970s by Mike Riddle and licensed to Autodesk in the 1982 for their AutoCAD application

.dxf

File extension dxf is used for Drawing Exchange Format developed by Autodesk in an effort to create a stable exchange format between AutoCAD and other CAD software.

DXF (Drawing Exchange Format) drawing files from virtually any CAD system. An exchange format for CAD files. A format for storing vector data in ASCII or binary files; used by AutoCAD and other CAD software and convertible to ARC/INFO coverages.

.ifc

The ifc file extension is associated with the Industry Foundation Classes, an open file format used to describe building and construction industry data supported by various BIM (Building Information Modeling) apps.

The ifc file contains model created in the Industry Foundation Classes (IFC) format.

.sat

The sat file extension is mainly associated with Spatial 3D ACIS modeling engine and used for one of the default 3D formats.

3D ACIS engine is supported by various CAD applications such as  Autodesk AutoCAD, CADKEY, IRONCAD, Vellum Solids, and several others CAD systems.

These files contain CAD representations of system components, which may be used to model objects in non-sequential mode.

.skp

File extension skp is nowadays best known for its use in SketchUp, a 3D modeling tool available for Microsoft Windows and Mac.

The skp files represent the default 3D models files created and saved in the application.

SKP models can be shared or placed within Google Earth online service.

Image Formats:

.bmp

The bmp file extension is commonly used for bitmap files - standard, non-compressed bit-mapped graphics format used in the Windows (and also OS/2).

The *.bmp files store graphics in a format called device-independent bitmap (DIB).

Bitmap images, also called raster images, use a grid (the bitmap or raster) of small squares known as pixels to represent images. Each pixel is assigned a specific location and color value.

.png

The png file extension is commonly used for images in Portable Network Graphics file format.

PNG is a bitmap graphics format similar to GIF, that uses image compression mainly for web purposes. PNG is a lossless format with 16.7 million colors, index color, grayscale, true color, transparency and also is streamable, which makes it superior to GIF. 

.jpg

The jpg file extension is associated with JPEG (Joint Photographic Experts Group) file format. JPEG is a lossy image compression algorithm that significantly reduces the file size of the original image at the cost of quality. The higher the compression ratio the lower the quality of the .jpg file

.jpeg

The jpeg file extension is mainly associated with JPEG (Joint Photographic Experts Group) file format.

A .jpeg file extension is sometimes used instead of the far common jpg file extension, however the format is the same.

tif

The tif file extension is traditionally used for Tagged Image File Format - one of the most widely supported lossless (does not lose information during compression) file formats for storing bit-mapped images (both PCs and Macintosh computers).

TIFF/IT is a standard for the exchange of digital adverts and complete pages. The .tif files only contain bitmap data, no vector data. They are not rasterized (although they could be) but may also contain 256 gray-levels per channel.

Typically, TIFF images larger than 4GB are called BigTIFF and use the same tif file extension.

Other Formats

.ODBC

Open Database Connectivity enables compatibility of data shared by architects, which is linked through application developers to write a single application while accessing data sources. For Architectural BIM Services Companies which have huge database wherein they can use ODBC to let specific tools be connected with a program.

HTML

The html file extension is mainly related to the Hypertext Markup Language that provides means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. It is the main language for writing web pages.

HTML formats texts, tables, images, and other content that will be displayed on the page that can be viewed using any web browser.

.TXT

The txt file extension is traditionally used for simple text files. Many MS-DOS, Unix, Windows applications and text editors used this file extension for common text file. Only character encoding charset may vary from simple ASCII to UTF etc.

.gbxml

The gbxml file extension is mainly related to a special XML format called Green Building XML schema.

The gbXML open schema helps facilitate the transfer of building properties stored in 3D building information models (BIM) to engineering analysis tools.

Today, gbXML has the industry support of leading 3D BIM vendors such as Autodesk, Bentley, and Graphisoft.