Trim, Split and Extend in 3D

In Design’s 3D view, choose Trim, Split or Extend from the left rail. Trim removes part of an object, Split divides it, and Extend grows an eligible end towards a reference. These tools use a 3D reference; the similarly named 2D path tools have a separate workflow. You can select targets before starting, or pick them after the reference.

In the Tool Guide, Pick → Face lets you click a flat face as the reference plane. A curved reference face is refused. Use workplane uses the currently locked workplane; if none is available, the app asks you to establish one. Trim and Extend also support Pick → Object: point at the relevant edge or face of another object. Split works with a face or workplane, not an object reference.

For Trim and Extend, set Overhang: positive goes past the reference and negative stops short. For face/workplane Split, set Offset from the reference. Use the project’s metric or imperial length format, or the supported typed cursor input. Set these values before the click that completes the operation. Overhang does not apply where object-reference trimming removes an overlapping volume; read the preview note.

After choosing the reference, point at the target and inspect the preview. For Trim with a face or workplane, click the part you want removed. Part to remove can lock that side; its choices describe above/below or in front of/behind the reference. A locked choice takes precedence over the clicked side. For Split, click the object to divide; for Extend, click the end to grow. A useful plain click commits immediately rather than waiting for a second confirmation.

Hold Shift while clicking to build or adjust a target list without cutting it immediately. Enter or Apply advances the current step: first confirm the targets when required, then complete the operation once the reference and required side are known. Follow the Tool Guide’s current instruction. Preselected targets can complete sooner: Extend can commit when you click its reference face, and an object reference can commit as soon as it is picked.

Supported solids and Structure members can use this workflow; in Reshape it acts through the open object’s selected-face editing scope. Structure members using an object reference must belong to the same open structure as that reference. Whole wizard objects can be refused with Edit members, or use their supported path-specific route. Curved references, unsuitable ends, missing intersections and operations that would remove a whole object can be refused. Read the reason and any Left unchanged list; an operation can change eligible targets while leaving others unchanged.

A successful operation keeps the reference and leaves the tool active for more targets. Esc clears typed input first, then steps back through a locked side, chosen targets and the reference; a further Esc returns to Select when nothing remains. It does not reverse a completed cut. Use Undo for a committed operation; targets changed together by that operation are restored together. Inspect the result even when the tool cannot draw a removed-part preview for that shape.