kirra-docs

Clip Surface

Cuts a surface or a solid with a KAD polygon and keeps the part inside, the part outside, or both. Use it to trim a pickup to a blast boundary, split a design solid at a limit, or break a solid into blocks with several cutters at once.

Clip Surface or Solid dialog

Clip with one polygon (Single)

  1. Click Clip Surface on the Surface toolbar. The Clip Surface or Solid dialog opens on the Single tab.
  2. Choose the Surface, or click its target button and click it in 3D. A banner says how it will be clipped:
    • Closed solid — cut by the polygon extended straight up and down; both pieces are capped, so volume is conserved.
    • Open surface — cut in plan view; no caps.
  3. Choose the Clip polygon: click its target button and then a closed polygon, or choose it from the list. The line under it confirms “✔ Clip by: …”.
  4. Choose the Mode: Keep inside, Keep outside or Dissect (split, keep both).
  5. For a solid, leave Close repair post steps on — it tidies each piece after the cut.
  6. Click Execute. A progress window with a timer runs the clip.

Note: The list starts on Choose a polygon…. Clicking Execute before you choose one gives “Pick the clip polygon first.”

Clip a solid with many cutters (Batch)

  1. Open the Batch tab and choose the Solid. Batch works on closed solids only.
  2. Under Add cutter, choose a polygon or line, or switch the target button on and click them on the canvas one after another. Click ＋ to add each to the Cutters list.
  3. Choose the Mode:
    • Dissect — divide into all pieces (polys + lines)
    • Keep inside — one chunk per polygon (closed only)
    • Keep outside — one remainder (closed only)
  4. With Dissect, tick Extend lines to fill gaps if a line stops short of the solid’s edge.
  5. Click Execute.

Lines only work with Dissect; the keep modes need closed polygons.

What you get

The surface is replaced by the pieces, in the same layer, and the whole clip is one undo step.

Mode Piece names
Keep inside / Keep outside Pit (inside) / Pit (outside)
Batch, keep inside Pit (Cutter1), Pit (Cutter2) … and Pit (remainder)
Dissect Pit (piece 1), Pit (piece 2) …

Open-surface pieces keep the original colouring. Solid pieces are hillshaded — the inside piece a little lighter and the outside a little darker — and dissected pieces take a colour each. The status line reports the result, including each solid piece’s volume. If it ends with “run Clean Mesh to fully close”, open Clean Mesh on that piece.

Troubleshooting

Symptom Cause Fix
“Pick the clip polygon first.” No polygon chosen yet Pick one, or change the list
“Clip produced no result — the boundary may not overlap the surface.” The polygon misses the surface Check both in plan
“Batch clip currently supports CLOSED SOLIDS only.” The Batch target is an open surface Use the Single tab
“Keep inside / Keep outside need CLOSED polygon cutters.” A line is in the cutter list Switch to Dissect, or remove the line
“Dissect: no division — the cutters didn’t cross the solid” The cutters stop short Extend them, or tick Extend lines to fill gaps

Other ways to use it

Method Result
Dissect (split, keep both) Both sides kept as separate surfaces
Batch target button left on Click cutter after cutter, then ＋ each
A Surface Intersection result as the polygon Clip one surface where it meets another
Ctrl+Z after a clip Puts the original surface back