Precision editing

Every depth drag in HelioCad — push/pull on a face, extrude depth, fillet radius, hole depth, and move — runs through one shared drag engine, so the same habits work everywhere. A plain drag snaps to the unit step, holding Shift switches to fine steps, and holding Ctrl (Cmd on macOS) gives a free, unsnapped drag.

As you drag, a graduated ruler appears along the drag axis so you can read the distance against the model, and a value chip follows the cursor with the current number. The chip is editable: click it and type an exact value to land on it precisely.

Press K to toggle 3D snapping. With it on, drags and placements snap to vertices, edge midpoints, and face centers on the model, so a hole lands on the center of a face and a moved body seats against an existing edge. The Snap toggle in the view puck's overlays shows the current state and toggles it with a click.

The status capsule at the bottom left keeps you oriented: a scale bar that adjusts as you zoom, and the cursor's XYZ position in model coordinates. When you select geometry or commit an edit, a brief flash on the affected faces confirms exactly what changed.

Every step of the part is listed in the Features lane on the left, and the filmstrip above the dock shows the same steps as dots that unfold into thumbnails on hover. Hover any step and its footprint lights up on the model, so you can find which fillet or hole a step belongs to without reading its name. Click a step in the lane, or drag across the filmstrip's step counter, to roll the model back to that point in its history — later steps are suppressed, not deleted, and stepping forward replays them.

Double-click a fillet, chamfer, extrude, shell, offset, hole, or draft step to re-arm its gizmo on the model and edit it in place with the same drag and value-chip controls you used to create it. Apply replaces that step and replays everything after it. Before you commit, you can preview the exact rebuild and compare the original against the candidate, so a radius change deep in the history is never a leap of faith.

The Parameters window (press P, or open Inspect ▸ Parameters in the dock) shows a slider and an exact-value field for every parameter in the model, and the Parameters section at the foot of the Features lane lists them for quick edits. Nudge with the slider or type the number, and the model rebuilds. Edits are transactional — each one lands as a replayable change in the history, so you can undo it or roll past it like any other step.

Move and Scale accept typed values as well as drags, so you can translate a body exactly 12.5 mm along Y or scale a part by a precise factor. Linear and circular patterns stay editable after the fact: change the count, spacing, or angle and every instance updates.

With the Measure tool active (M, or Measure on the view puck), hover any face or edge for an instant readout: the entity type, area, perimeter, radius, and the ΔX / ΔY / ΔZ extents. Pin keeps a pair's readout on screen while you keep working. Distances are computed on the exact B-Rep geometry, not on the display mesh, so a measured radius is the modeled radius.

Auto Measure lays out a set of engineering dimensions over the model and tours them one at a time, so you can check a part the way a reviewer would. For mass, volume, surface area, and center of mass, open Inspect ▸ Mass properties in the dock, or press Q.