How to Use Thumbnails in BricsCAD Mechanical BOM Tables
Quick answer: Thumbnails are preview images of parts included in a BOM table, generated from each part’s 3D geometry, confirming and expanding the Thumbnails column mentioned on this hub’s BOM Manager and BOM Columns pages. Once a BOM table with thumbnails is added to a layout or model space, those images store as attachments, manipulable via the Attachments panel. Until the document is saved, they live in a temporary folder; saving moves them to a specified folder (usually bom_thumbnails inside the drawing’s own folder).
Add thumbnails to a BOM simply by adding a Thumbnails column, then adjusting its properties as needed. A single BOM table can contain multiple thumbnail columns, each with its own settings.
Adjustable Thumbnail Properties
- Path: the folder images move to once the document is saved.
- View type: the camera orientation, matching the options of the Look from widget.
- Visual style: the style applied to parts, defaulting to the document’s current visual style, though any available style works. A special
BM_tangentstyle is also available, imitating a draft-quality black-and-white drawing view. - Background color: any color, or transparent (transparent backgrounds generally take longer to generate).
- Size: width and height in pixels, with global Default thumbnail width and Default thumbnail height settings controlling the starting default.
Performance and Updating
Thumbnail generation can take considerable time on large assemblies. By default, thumbnails update automatically whenever the model changes. To force the BOM to reuse existing thumbnails with their current settings, even once they no longer match the part’s actual geometry, uncheck Automatically update thumbnails in the Bill of materials defaults setting.
You can also temporarily disable a thumbnail column so it stops generating thumbnails altogether, set its Enabled property to No in the BOM Manager panel; re-enabling it automatically generates any missing thumbnails.
Frequently Asked Questions
Where do BOM thumbnail images actually get stored once I save my drawing? A specified folder, usually named bom_thumbnails inside the drawing’s own folder; before saving, they sit in a temporary location.
Why would I use a transparent background for a thumbnail instead of a solid color? Purely a visual preference, though be aware transparent backgrounds generally take longer to generate than solid ones.
Can I stop thumbnails from regenerating every time I change the model? Yes, uncheck Automatically update thumbnails in the Bill of materials defaults setting to force reuse of existing thumbnails.
What does the BM_tangent visual style do for a thumbnail? It imitates a draft-quality black-and-white drawing view, rather than a fully rendered image.