Try Trim on a circle and line
- Open a sketch, draw a circle, then draw a line across it with both ends extending outside the circle.
- Choose Trim on the CAD tool rail, or press X.
- Hover over one line end outside the circle. Only that tail should highlight in red. Click to remove it, then repeat at the other end.
- The remaining line now ends exactly on the circle. Return to 3D > Push/Pull to select either enclosed region.
- Return to the sketch, activate Trim and hover over one side of the circle. Click to remove that circular section; the other side remains as editable arc geometry.
- Use Undo to restore the circle. Each click is one undo step. Save and reopen to check the resulting sketch.
01 · SELECT A SECTION
Preview before removing
In an open CAD sketch, activate Trim and hover over a line, circle, circular arc, rectangle side or ordinary spline. A red highlight shows the exact section that a click will remove. The nearest intersections on either side bound the section; an open line, arc or spline can also end at its own endpoint. Rectangle corners bound each side. You do not need to select the cutting boundaries first.
Click once to apply the preview. Trim stays active for more clicks. Press Esc or choose another tool when finished. Middle-mouse pan and wheel zoom remain available while trimming.
If intersections do not bound a removable section, Trim highlights the entire curve and says that the next click will remove it. A circle or closed spline needs at least two distinct intersections to leave a remaining section. On a rectangle, a whole-side preview removes only that side. Hover alone never changes the sketch.
RECTANGLES
Trim one side or part of a side
- Draw a 100 × 60 mm rectangle. In the same sketch, draw two vertical lines crossing its top and bottom sides, about 30 mm and 70 mm from the left edge.
- Press X and hover over the top side between those lines. Only the section between the crossings highlights.
- Click once. The middle section is removed, leaving two top pieces and the other three sides as ordinary lines. The two crossing lines stay unchanged.
- Return to 3D > Push/Pull. The left and right regions remain enclosed and selectable; the middle region is now open.
- Undo to restore the original rectangle. Try a side with no internal crossings: the preview says remove this side, and one click leaves the other three sides.
The first trim converts the remaining rectangle outline into separate editable lines. Use Line endpoint editing or trim another piece directly. Rectangle width, height and corner controls no longer apply to the converted outline; Undo restores the original rectangle and its controls.
Existing solid features that reference the original rectangle report a changed or missing source after conversion. Their definitions remain in the model and can still be saved. Restore the rectangle with Undo, or recreate the affected features from the remaining closed regions.
SPLINE CLEANUP
Trim curves while keeping their shape
- In one sketch, draw a circle and an open S-shaped spline that starts and ends outside it. Check that the actual curve crosses the circle twice.
- Press X and hover over a spline tail outside the circle. Click to remove the highlighted section, then repeat on the other tail.
- The remaining spline ends exactly on the circle. Return to 3D > Push/Pull to extrude either enclosed region.
- Undo the trims and try removing the middle of the spline instead. Two separate tails remain.
- Try trimming a circle, rectangle side, line or arc where it meets a spline. Splines act as cutting boundaries as well as trim targets.
Open and closed unmirrored splines are supported, including crossings between two splines. A closed spline is trimmed around its actual loop, including sections that pass through its start/end point.
The remaining geometry keeps the original curve shape. It is stored as one or more joined, editable cubic spline pieces, with four control points per piece. A long spline can therefore become several objects even when its remaining outline is continuous. The joins start at the same exact positions, but later handle edits are independent; moving one piece can open a gap.
Use Select and the gold spline handles to edit a piece. Each trim is one Undo step, which restores the original spline and its control points. Save/open retains the resulting spline pieces. Existing solid features referencing the replaced spline retain their definitions and report a rebuild issue; undo or recreate them from the intended current regions.
Mirror-linked splines and their reflected halves are excluded from Trim. Select the source and choose Remove mirror before trimming it. Self-crossing, overlapping or unresolved near-touching splines need simpler, unambiguous geometry first. A trim that would leave an individual piece shorter than 0.1 mm is blocked; adjust the cutting boundary.
02 · EDITABLE RESULTS
Keep exact lines and arcs
Removing a line end shortens that line. Removing a section from its middle leaves two separate line objects. Trimming an arc keeps its circular geometry and can leave one or two arcs.
Trimming a circle converts the remaining portion into ordinary circular arcs with the original radius. A remainder larger than a semicircle uses two joined arcs because each Cadivari arc has a maximum sweep of 180°. Select those arcs with the normal Arc editing controls.
The result is an actual geometry edit, saved with the sketch. One Undo restores the complete source curve, including both pieces after a middle trim.
03 · CONNECTED MODELLING
Regions update with the sketch
The enclosed regions used by Push/Pull are recalculated after Trim. Removing an overhanging tail can clean up a sketch while leaving its enclosed regions intact. Removing a dividing section may merge regions; removing an outer boundary may open them.
Existing solid features rebuild when their stored references still resolve. If a trim removes or changes a referenced boundary, Cadivari retains the feature definition and reports a rebuild issue. That definition remains saved when you reopen the project. Undo the trim to restore the source, or remove the affected feature and recreate it from the intended current region.
Trim sketch geometry before assigning CAM operations. Trim blocks edits to curves referenced by a CAM operation or stored CAM path source. Remove the affected operations and path source first, then rebuild them from the finished sketch.
REFERENCE
Controls
CURRENT SCOPE
Supported geometry and limits
- Trim targets: ordinary lines, circles, circular arcs, individual rectangle sides and unmirrored open or closed splines.
- Cutting boundaries: visible lines, circles, circular arcs, rectangle edges and unmirrored splines in the same sketch. Rectangle sides can both stop a trim and be trimmed. Trimming one converts the remaining outline into lines.
- Splines: supported as both targets and cutting boundaries. Mirror-linked splines and their reflected halves are excluded. Self-crossing or overlapping splines must be simplified before trimming.
- Hidden geometry and projected/reference edges do not provide cutting boundaries. Real gaps remain open; Trim does not extend a short curve.
- Tangencies do not divide a curve. Overlapping strokes are blocked because the intended section is ambiguous. Move slightly away from an exact intersection to choose the side to remove.
- A trim that would leave a piece shorter than 0.1 mm is blocked. Adjust the boundary or use Select and Delete to remove the entire curve.
- Curves controlled by an editable fillet, live Combine result or rosette cannot be trimmed while that relationship is active. Release the relationship or edit the source in its owning tool. See releasing a fillet relationship.
- CAM-linked sources are protected as described above. Drag-to-trim and Extend are not included yet.