How to Trim Entities in BricsCAD

Quick answer: TRIM clips or trims entities using cutting entities you select first. This confirms the mirror image of what’s covered on this hub’s Extending Entities page: hold Shift while selecting an entity here, and it extends to the cutting entity instead of trimming.

What Can Be Trimmed and What Can Serve as a Cutting Entity

Trimmable entities: lines, 2D and 3D polylines, arcs, circles, ellipses, elliptical arcs, splines, rays, and infinite lines. This list is actually broader than the entity types EXTEND can work with, which is limited to arcs, lines, 2D polylines, and rays.

Cutting entities: lines, splines, polylines, arcs, circles, elliptical arcs, ellipses, rays, infinite lines, and layout viewports, one entry more than EXTEND‘s boundary entity list, which doesn’t include elliptical arcs. Entities within a block can also be selected as cutting entities.

Handling Non-Coplanar Boundaries

With EDGEMODE on, entities extend to an implied edge of the boundary entities, the same behaviour covered on the Extending Entities page. If the cutting entity isn’t in the same plane as the entity you’re trimming, PROJMODE controls how the intersection is calculated: project to the XY plane of the current UCS, project to the current view plane, or true 3D mode with no projection.

Trimming Entities

1. Launch TRIM.
2. Select a cutting entity.
3. Select more, or press Enter to stop selecting.
4. Select an entity to trim; it trims by the cutting entity.
5. Select more entities, or press Enter to stop.

Things Worth Knowing

• Entities already selected when you launch TRIM are automatically used as cutting entities.
• Hold Shift while selecting an entity to extend it to the cutting entity instead of trimming it.
• Use Fence or Crossing selection to select several entities at once.
• Quick mode makes every entity automatically act as a trim edge.

Frequently Asked Questions

Can I extend an entity while running the TRIM command, without switching commands? Yes, hold Shift while selecting the entity, this extends it to the cutting entity instead of trimming it.

Can TRIM work with more entity types than EXTEND? Yes, its list of trimmable entities is broader, including 3D polylines, circles, ellipses, elliptical arcs, and splines that aren’t extendable with EXTEND.

Can entities inside a block be used as cutting entities? Yes, entities within a block can be selected as cutting entities for TRIM.

Do I need to select cutting entities first, or can they already be selected? Either works, entities already selected when you launch TRIM are automatically treated as cutting entities.