Free online IGS to BMP converter

What the IGS format is

IGS, also written as .igs or .iges, is the file extension commonly used for IGES (Initial Graphics Exchange Specification), a neutral CAD exchange format. It stores curves, surfaces, wireframes, and related geometric entities so models can move between mechanical-design and engineering applications.

IGES files are created or exported by programs such as Autodesk Inventor, CATIA, SolidWorks, Siemens NX, FreeCAD, and other CAD systems. You typically encounter them when receiving a supplier model, exchanging legacy engineering data, or importing a surface model into a different 3D modeling application.

What the BMP format is

BMP (Bitmap Image File) stores a raster image as a grid of pixels. It is supported by Windows graphics software, image editors, office applications, documentation systems, and many basic viewers.

BMP is useful when a CAD model must appear as a fixed picture rather than remain editable. It has simple encoding, does not normally require compression, and can preserve exact pixel values. The tradeoff is that BMP files are often much larger than PNG or JPEG files at the same dimensions.

How to convert IGS to BMP

Using the online converter

101convert.com can convert an IGS file to BMP without installing CAD software:

1. Open the IGS-to-BMP converter on 101convert.com.
2. Select the source file with the .igs or .iges extension.
3. Choose BMP as the output format.
4. Start the conversion and wait for the model to be rendered.
5. Download the resulting bitmap file and open it in an image viewer or editor.

If the converter exposes rendering settings, set the image width and height before conversion, choose the required view or orientation, and select a background color that contrasts with the model. A higher resolution produces a clearer technical illustration but increases the BMP file size.

Using desktop CAD software

For a controlled camera angle or more reliable rendering, open the IGS file in a CAD application such as FreeCAD:

1. Use File → Open and select the IGS file.
2. Fit the model to the viewport and select the required standard or custom view.
3. Use the application’s image export or viewport capture function, if available, and choose BMP as the output type.

CAD programs differ in their BMP export support; some export only PNG or other image formats. In that case, save the rendered view as PNG and convert that image to BMP with an image editor while retaining the chosen pixel dimensions.

Quality and compatibility considerations

This conversion is a 3D-to-2D rendering, not a format-preserving CAD conversion. The BMP contains pixels only: curves, surfaces, dimensions, layers, materials, units, and editable model structure cannot be recovered from it.

IGES files can contain multiple entities, incomplete surfaces, or geometry that different CAD kernels interpret differently. If the rendered model looks incomplete, repair or verify the IGS file in a CAD program before exporting the image. Orthographic views are generally preferable for technical documentation; perspective views communicate shape but can change apparent proportions.

BMP supports several color depths, including 24-bit color and 32-bit color with an alpha channel, but not every viewer or converter preserves transparency. Use a solid background when the image must work reliably in office documents or older Windows software.