Convert CGM to BMP — Free Online Converter
Convert Computer Graphics Metafile (.cgm) to Bitmap Image (.bmp) online for free. Fast, secure image conversion with no watermarks or registration....
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Upload your .cgm file by dragging it into the upload area or clicking to browse.
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Click Convert and download your .bmp file when it's ready.
About CGM to BMP Conversion
CGM (Computer Graphics Metafile, ISO 8632) is the vector illustration format mandated by aviation (ATA iSpec 2200), defense (NATO STANAG 4602, S1000D), and industrial documentation standards. CGM files contain technical drawings — wiring diagrams, exploded-view assembly illustrations, maintenance procedure visuals, and schematic representations — used in aircraft maintenance manuals, military equipment documentation, and heavy machinery service guides. BMP (Bitmap) is the simplest uncompressed raster format, storing raw pixel values without any compression.
Converting CGM to BMP produces exact pixel data from technical illustrations, needed when automated systems must analyze illustration content pixel-by-pixel — optical character recognition on diagram text, machine vision comparison of illustration revisions, and quality assurance pipelines that verify rendered illustration accuracy against reference images.
Why Convert CGM to BMP?
Automated documentation verification systems in aviation and defense often require uncompressed raster input for pixel-level comparison. When a technical illustration is updated in a CGM authoring tool, the updated version must be compared against the previous version to identify all changes. BMP provides raw pixel data without compression artifacts that could create false differences in comparison algorithms.
BMP is also required by certain legacy documentation management systems. Older Technical Data Management Systems (TDMS) deployed at military depots and airline maintenance facilities were built decades ago when BMP was the standard image format. These systems ingest BMP files for indexed storage and retrieval. Upgrading these mission-critical systems is expensive and slow, so new illustration conversions must continue to produce BMP output.
Common Use Cases
- Convert CGM aviation illustrations to BMP for automated revision comparison in documentation change management systems
- Produce BMP reference images from CGM technical drawings for machine vision quality assurance pipelines
- Export CGM military documentation illustrations as BMP for legacy Technical Data Management Systems
- Generate BMP output from CGM engineering diagrams for optical character recognition on text labels
- Create BMP versions of CGM maintenance illustrations for legacy display systems in repair depots
How It Works
LibreOffice imports the CGM file using its metafile parser, reading CGM binary or clear-text encoding to extract vector elements: polylines, polygons, circles, arcs, text labels, and fill areas. The vector content is rasterized at the specified resolution with anti-aliasing applied to diagonal lines and curves. The rendered pixel data is written as a Windows BMP v3 file with 24-bit RGB color depth. No compression is applied — every pixel is stored as raw RGB triplets. Resolution metadata is embedded in the BMP header for correct physical sizing.
Quality & Performance
The BMP output is an accurate rasterization of the CGM technical illustration at the specified DPI. Line work is rendered with anti-aliasing for smooth appearance. Text labels are rasterized with available system fonts (original CGM fonts may be substituted). Fill patterns and hatch marks render accurately for standard definitions. Since BMP applies no compression, the rendered output is stored with zero degradation. File sizes are large due to the lack of compression — a detailed technical illustration at 300 DPI can exceed 30 MB.
Device Compatibility
| Device | CGM | BMP |
|---|---|---|
| Windows PC | Partial | Native |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No | No |
Tips for Best Results
- 1Use BMP only when raw pixel data is specifically required — PNG provides identical quality with 60-80% smaller file sizes
- 2Choose 300 DPI for technical drawings with fine line work and small text labels
- 3For automated illustration comparison, BMP's uncompressed pixels eliminate false differences from compression artifacts
- 4Verify text rendering after conversion — CGM fonts may be substituted with available system fonts
- 5Plan for large file sizes when converting CGM collections to BMP at high resolution
CGM-to-BMP conversion produces uncompressed raster output from technical illustrations, essential for automated revision comparison, machine vision analysis, and legacy documentation management systems in aviation and defense.