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CAD tip # 8754:
Question
Size of the thumbnails saved with a drawing is controlled by the THUMBSIZE variable (stored in Registry, default=3). Higher values than the default "3" are by default applied only on 3D drawings. This can be overridden with enabling the variable THUMBSIZE2D.
How does this setting influence the total size of DWG files?
Especially with simple smaller drawings, the increase of the total file size can be quite substantial - up to 2x of the size without any thumbnail (THUMBSAVE=0). The size is also influenced by other factors, e.g. by image compression or by incremental saving of changes into DWGs. The following sample is not influenced by these factors but still consider it an example only:
| THUMBSIZE | Thumb resolution | File size | Size increase |
|---|---|---|---|
| off | N/A | 62 276 | 0% |
| 0 | 64 x 64 | 63 555 | +2.1% |
| 1 | 128 x 128 | 64 579 | +3.7% |
| 2 | 256 x 256 | 65 603 | +5.3% |
| 3 | 512 x 512 | 70 723 | +13.6% |
| 4 | 1024 x 1024 | 83 011 | +33.3% |
| 5 | 1440 x 1440 | 94 275 | +51.4% |
| 6 | 1600 x 1600 | 99 395 | +59.6% |
| 7 | 1920 x 1920 | 108 611 | +74.4% |
| 8 | 2560 x 2560 | 132 163 | +112.2% |
In complex DWGs, the total thumbnail (in the largest resolution) can add up to 10MB to the drawing file size.
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