# v0.5.0 — Hole-pitch measuring, 3-point section planes and STEP export

## ✨ New features

**Measure hole-to-hole pitch in two clicks — snap to circle centers**
* Point / Distance / Align picks now **snap to the center of a circular edge** when you click near
  a hole or a round boss — measure connector pin pitch by simply clicking two hole rims.
* Vertex snapping still works; whichever feature is closest to your click wins.

**Keyboard shortcuts and Esc**
* Measure modes now have hotkeys: **P** point, **D** distance, **E** edge, **F** face, **C** circle,
  **A** angle, **M** face-to-face. Press the same key again to go back to browsing.
* **Esc** cancels an in-progress multi-step measurement first (keeping the mode), then exits the
  mode, then closes the manipulator — no more re-clicking toolbar buttons after a mis-pick.

**Standard views and orthographic projection**
* One-click **Iso / Front / Top / Right** view buttons (Z-up, mechanical convention).
* New **orthographic ⇄ perspective** toggle — check dimensions without perspective distortion.
  The 3-axis manipulator stays perfectly aligned in both projections.

**Assembly tree: search, isolate, volume**
* A **search box** above the tree filters nodes by name (ancestors and children of a match stay
  visible, branches auto-expand) — find one part in a hundred instantly.
* Right-click any node: **Isolate** (show only this node), **Invert visibility**, **Show all**.
* Right-click **Volume / centroid**: closed solids get mesh-based volume, a centroid marker in the
  view, and overall L×W×H. Node tooltips now show each part's bounding size too.

**Cut along any plane — 3-point section + numeric position**
* The section axis picker gains a **"3-pt"** option: click three points on the model to define an
  arbitrary cutting plane, then sweep it with the position slider as usual.
* The position value is now also an **editable number field** (0–100 %).

**Interference check across 3+ files**
* The check now accepts **two or more** visible files and tests **every pair**, reporting each
  pair's result (intersection lines or minimum gap) plus a summary of how many pairs collide.

**Hand off your alignment — export the scene as STEP**
* New **📤 STEP** button writes all visible parts **at their current aligned positions** into a
  brand-new STEP file — mate connectors in STPViewer, then hand the assembly to any CAD.
  Original files are never modified.

**Quality of life**
* Window size/position, mm ⇄ inch choice and the **last 10 opened files** (▾ next to Import) are
  remembered between sessions.
* The tree and measurement panels are now **resizable** with drag splitters.

## 📦 Downloads

Two builds are produced:

| Build | Needs .NET 8 Desktop Runtime? | Notes |
|-------|-------------------------------|-------|
| **Standard** (`STPViewer_v0.5.0`) | ✅ Yes | Smaller; for machines that already have the runtime |
| **Portable** (`STPViewer_v0.5.0_portable`) | ❌ No | Runtime bundled — unzip and run, no install / admin needed |

Run `STPViewer v0.5.0.exe`.

**Full changelog:** [v0.4.0...v0.5.0](https://github.com/ETWen/STPViewer/compare/v0.4.0...v0.5.0)