What's new

Vertical plunges are now converted too. A plunge now rapids down to your Rapid Z min height before feeding the rest of the way, which saves real time on files with many holes or re-entries.
Converting shows an improved summary of the changes and the cycle time saved.
Changed lines are marked in colour in the listing, added lines in green.
Undo restores your original program at any time, and Save writes a new file with -rapids added to the name.

- You can now view the loaded file by dropping down the roller blind from the file load box.
- Convert slow G1 feeds above your stock into G0 rapids and save the converted file.
- Improved simulation accuracy
- Improved light mode rendering.
- Added more and improved tool tips.

- Demos start playing immediately when picked.
- 3D stock removal now defaults on for desktops and tablets, off on phones.
- New "Stock Z top" box: leave blank for auto or type your own. Programs cutting down from Z0 are detected and get the right block height.
- First tool load into an empty spindle now takes half the tool change time, for a more accurate cycle time.
- The Good to know panel fades out after a 5 seconds.

The viewer now carves a virtual stock as your program plays. The stock is sized automatically from the toolpath, the cut matches the tool shapes in your tool table (flat, ball nose, bullnose and drill point), and the block is semi-transparent so you can watch the tool working inside the cut. Scrubbing backwards re-simulates the stock to that point in the program, and a rapid that ploughs through material is visible in the carved stock.

This works in the app, in embeds and in the homepage demo, is user selectable, and it is on by default. It needs WebGPU, which current Chrome, Edge and Firefox provide. On a browser without WebGPU the toggle is disabled and everything else works as before.

The embed page now has two options: square corners and light mode. Tick them and the snippet, the full example page and the live preview all update together, so you can see exactly what you are getting before you copy anything. The options work through URL parameters (squarecorners=default and lightmode=default), they can be combined, and a plain snippet with no parameters keeps the standard dark mode with rounded corners.

The mobile menu now shows all six items, and a footer layout bug that let every page scroll sideways into empty space is fixed. The 3D view now recovers automatically when a phone resets its graphics under rotation, which used to leave a blank viewer after rotating the screen.
On small screens the viewer's control panels are no longer hidden. They collapse into drawers with a handle on each edge of the viewer. Tap the handle to slide the settings or the position readout over the model, and tap the model or the handle again to put them away. In landscape the page header steps aside so the viewer gets the full height, and a ridged strip down the right edge of the viewer gives you a place to scroll the page when the model is using your touch for orbiting.

Fixed an issue where the G-code viewer could occasionally fail to start on phones, requiring a manual page refresh.
The viewer now recovers automatically from brief network drops and poor reception. Improved robustness of 3D library loading.

Subprogram calls now execute — M98 with repeat counts, Haas M97, LinuxCNC o-calls, nested and expanded inline. A tombstone program that used to simulate six lines now times all 48 holes; see the new Tombstone demo. Anything unresolvable is named in the notes. The planner also honours G61/G09 exact stop and G64 P blend tolerance, and a new Jerk setting in Machine dynamics gives jerk-limited controllers true S-curve timing — leave it at 0 and nothing changes. Plus six new Learn articles and sourced comparisons with NCViewer, CAMotics and CIMCO Edit.

Two boring-and-spot-drilling behaviours the clock was missing now count. G82 and G89 hold the tool at the hole bottom for the programmed P dwell — read in your controller's dialect, milliseconds or seconds, just like G04 — and playback pauses there with a countdown so you can see the time being spent. G85 and G89 now retract at feed instead of rapid, the way a boring or reaming cycle really moves with the tool still engaged on the way out — previously these holes simulated almost twice as fast as they run. Spot-drill patterns and reamed bores land noticeably closer to true cycle time; a plate of holes with a half-second dwell each is no longer a free lunch.

Machine dynamics has a new Jerk field (mm/s³ or in/s³). Modern industrial controllers — Fanuc AICC, Siemens, Heidenhain, Haas smoothing — limit how quickly acceleration itself can build, which makes real cycle times a little longer than a pure trapezoidal model predicts, especially on detailed, short-move toolpaths. Set Jerk to your machine's value and the estimate accounts for it: acceleration ramps use true S-curve timing and corner speeds respect the centripetal jerk limit. Leave it at 0 (the default) and nothing changes — the planner stays pure trapezoidal, which is correct for GRBL, Mach, LinuxCNC and most hobby machines. Typical values run 5,000–20,000 mm/s³ for hobby-class machines and 20,000–100,000+ for industrial VMCs; if you don't know yours, start around 20,000 and tune until the sim matches your machine's actual cycle time.

The simulator now runs rigid tapping (G84/G74) with spindle-reversal time, G28/G30 reference returns to a home position you set in Machine dynamics, feed-per-revolution (G95), and canned-cycle L repeats. Dwell units follow your controller's dialect automatically — Fanuc/Haas integer-millisecond dwells and LinuxCNC/GRBL seconds are both read the way your machine would run them — and nothing after M02/M30 is drawn or timed any more. Plus eight new warnings that tell you exactly what a file uses that the estimate can't fully model. If your programs use any of these codes, expect the estimate to now match your machine much more closely.

Cutting tools now render with the correct diameter and typical lengths.
A realistic tip shape is displayed for square, ball and bull nosed end mills and twist drills.

The file open box now also has the option to load a selection of demo files. Currently we have added the following...

UltraNC Sign.nc
M06 Tool Change
G04 Dwell Test
G73 Peck Drilling
G83 Peck Drilling

Added support for M06 Tool Change
Added support for G4 Dwell