Pleochroma in the browser

1What it is

The web app is the same Pleochroma, compiled to run inside a browser page. You open a design file (or start a new one from a template), edit its cutting instructions, let the solver close the meet points, look at the stone as a solid, a faceting diagram and a spectral render, read off the optical figures, and save the design back to your disk as a download.

It runs entirely on your own machine. The page is a set of static files; once it has loaded, your designs, your settings and the rendering all stay in the browser and nothing is uploaded anywhere. There is no account.

2What it can do

Designs

Start a new design from the template gallery (an empty design plus nine built-in templates, in one list). Open or import .asc, .gem, .gcs and Pleochroma's own self-contained .psdd design file, by file picker or by dragging files onto the page. The file reader is the desktop's, so a design file with concave tiers or tier relations (format versions 2 and 3) opens too; section 3 says what the web app does with them. Save the design as .psdd, or save .asc; an experimental .gcs export is in the File menu too. The cutting sheet downloads as an HTML page and the faceting diagram as a PNG. A design's frosted facets are kept in the .psdd file and survive a .gcs import.

CAD editor

The tier table with inline angle editing, keyboard and Ctrl+wheel nudging, undo and redo; the five-tab inspector (Tier, Preform, Optimize, Schedule, History); design settings, including a compact custom-material editor; and the guided walkthrough, the same ten-step worked example as the desktop. The angle and exact-scale fields of the tier form take plain arithmetic such as 41.5+0.3. The angle cell in the tier table also takes a relation that starts with =, for example =P1 - 2; the tier then follows the other tier and shows an = badge. A Good / Check / Problem badge sums up the design's checks, with a one-click fix where a safe one exists. The History tab lists every undo step and jumps to any of them. Concave tiers are listed after the flat ones with their tool line; they can be selected but not edited yet.

Mouse manipulation

In the Solid view, drag the angle, depth and index handles of a selected facet, or switch to Slice mode and cut a new facet by dragging a line across the stone. One drag is one undo step, and the design solves itself when you let go.

Solving

Solving anything but a small design runs in a background Web Worker, so the page stays responsive; a small design, or one whose last solve was fast, is solved directly on the page thread. A solve can re-run automatically after each edit (auto-solve). Optimize and Retarget run in the Worker with live progress, and Cancel stops the search between steps and keeps the best result found so far; a search that has not stopped 30 seconds after Cancel is ended and keeps no partial result. If the solve Worker fails three times for the same design, the page reports the failure and does not try again until the design changes.

Rendering

Path-Traced offers a progressive spectral render on your CPU cores and, in Chrome and Edge, on the GPU too for isotropic stones such as diamond and spinel, with a denoise once the picture settles. While the page loads it tests the GPU behind a loading bar and then says what the render uses (section 4). It uses the same physics, the same material catalogue and the same lighting choices as the desktop app, and it can load an HDR environment map (see the limits below). A design with concave tiers is rendered with its tools cut out, on the CPU and on the GPU, and a design's frosted facets are drawn as frosted. Export the result as a PNG in sRGB or Display P3.

Views

The Render view, the Solid view (facet picking and selection linked to the tier table, with the cuts of concave tools drawn) and the Diagram view (crown, pavilion and profile panels).

Optical figures

The metrics readout (brilliance, fire, scintillation, windowing, extinction) and the Tilt Performance dialog: brilliance, windowing and extinction against tilt, four azimuths of 181 points each. Both run in their own worker, so they never wait behind a solve. As on the desktop, the readout is scored under the light the view is lit with: with an HDR environment map loaded it is scored under that map and says so. The tilt sweep is scored under the lighting preset at the current light, as the desktop's dialog is, and the dialog notes this while a map is loaded. For a design with concave tiers, both are scored on the stone with its tools cut out, as on the desktop. The tilt sweep also scores a design's frosted facets as frosted; the metrics readout scores every facet as polished.

Session memory

Your settings and your place in the walkthrough are remembered in this browser, and the design you are working on is restored after a reload, but the app is not a store: save your design as a download before you leave.

3What it cannot do yet

These are the differences from the desktop application, as of this release. The right-hand column says where each one lives today.

4How it works

The desktop application and the web app are built from the same Rust code for the editor, the meet-point solver and the optics. The browser build compiles that code to WebAssembly and draws its interface with the same toolkit (Slint) inside a single canvas.

The heavy work runs in Web Workers, so the page stays responsive while it runs: rendering is spread over a pool of them, one per CPU core minus one, up to eight; solving larger designs, Optimize and Retarget share one more, and the optical figures have their own, so they never wait behind a solve. Small solves, the final tone map and merge of the rendered chunks, and the drawing of the Solid and Diagram views still run on the page thread. Rendering runs on your CPU cores. In Chrome and Edge it also runs on the GPU, for every Ray-Traced material class and for isotropic Path-Traced stones such as diamond and spinel; that needs WebGPU and is on by default.

While the page loads it tests the GPU behind a loading bar: it starts a GPU worker and asks for the adapter, checks the adapter's limits, compiles the kernels one by one and traces a small test picture. The CPU workers render meanwhile, and the bar's Hide button hides only the bar. Then the page says what the render uses, as a message and as a sentence that stays in the Render settings panel, for example “Rendering on the GPU (the adapter's name) with 7 workers on the CPU” or “Rendering on the CPU (7 workers)” followed by the reason. A browser without WebGPU, a Path-Traced stone the GPU cannot trace (anisotropic, color-zoned, more than 64 concave tools, or an environment map too large for the adapter) and any problem during the test fall back to the CPU, and the sentence names the reason. The GPU Rendering switch in the Render settings panel turns the GPU off; with it off, the page skips the test.

The result is kept per graphics card, browser version and shader build. An adapter that passed before only compiles the kernels again and skips the test picture. If the browser lost the GPU during an earlier run, the page does not test it by itself again: the panel shows the reason, Forget GPU Test Result lifts it, and Test GPU runs the test by hand.

Your settings, walkthrough progress and the GPU test result are remembered in this browser (local storage, per graphics card, browser version and shader build); the design you are working on is kept in the tab and in the browser's database so a reload brings it back, and otherwise in the files you save. There is no server side to the app: no upload, no account, no design database.

5Browser requirements

A current desktop Chrome, Edge, Firefox or Safari. The page needs WebAssembly, Web Workers and WebGL 2 (used to draw the interface), and it uses localStorage, sessionStorage and IndexedDB if they are available. WebGPU is optional, for GPU rendering in Chrome and Edge; without it the page renders on the CPU and says so. It does not need any special server settings. If WebGL 2 is disabled, the page says so instead of starting.

A tablet works for viewing and tapping. Touch arrives as mouse events, so Ctrl or Shift gestures and the keyboard shortcuts need a keyboard; everything they do is also reachable from the menus and buttons.

6Limits

• Render speed. Rendering runs on your CPU cores. In Chrome and Edge it also runs on the GPU for every Ray-Traced material class and for isotropic Path-Traced stones such as diamond and spinel; the page tests the GPU while it loads and falls back to the CPU on any problem. For Path-Traced, anisotropic and color-zoned stones render on the CPU only. For Ray-Traced, an HDR map beyond the GPU's limits falls back to the CPU. A few hundred samples per pixel take tens of seconds to minutes on the CPU, depending on the machine and the size of the view. The live view traces at most 960 pixels on its longest edge.
• Samples and export size. The live render takes 64 to 1024 samples per pixel. PNG export takes 16 to 4096 samples and up to 4096 pixels on the longest edge.
• HDR environment maps. A .hdr file is limited to 64 MiB and 8192 × 4096 texels in the browser. Each render worker, and the analysis worker that scores the metrics readout under the map, keeps its own decoded copy, so a large map is used on fewer render workers, with a message, rather than being downsampled. When the memory budget holds only one copy, a render worker keeps it and the readout falls back to the lighting preset and says so. A map that one worker cannot hold within the per-worker memory budget is refused.
• Long solves. A solve in the worker that runs for more than 60 seconds is stopped. A cancelled Optimize or Retarget that has not stopped after a 30-second grace period is ended, and keeps no partial result.
• Replacing a render. When a scene is replaced (for example by orbiting), the chunk being traced is aborted between row groups. A browser that cannot run the revocable-URL check the abort relies on runs that chunk to completion instead. A render worker that stays silent for 30 seconds while holding a chunk is replaced, up to three times in a row.
• Memory. The HDR environment-map copies the render workers and the analysis worker hold are held to a fixed memory budget of 1.5 GiB across those workers, which is why very large environment maps are limited. The budget covers those copies, not everything the page allocates.

7Get the desktop app

For the design library, the Rough planner, Path-Traced GPU rendering of anisotropic stones, remote rendering, Deep Solve, tilt video export, full-size master stills, the newer studio features (tutorials, cutting mode, editing concave tiers, variants) and the command-line tool, use the desktop application. On Windows the easiest way to install it is the Microsoft Store, which keeps it updated. It is also a ready-built download for Windows and Linux (see the downloads section), and it also installs from crates.io or builds from source; the commands are in the getting started section of the overview, and the application itself is described on the studio and CAD page. The two open the same files, so a design saved from the web app opens on the desktop and back. Video tutorials are on the Pleochroma YouTube channel.

Ray-Traced and Path-Traced

Choose Path-Traced or Ray-Traced in Render. Ray-Traced supports every material class on CPU and, where admitted, WebGPU. Its GPU uses at least four storage bindings, an independent kernel hash and crash record, and a 16×16 four-tap CPU/GPU self-check. Tool and HDR limits can fall back to CPU; engine refusals remain errors. No remote rendering is offered in the browser.

Ray-Traced is a deterministic approximation: one d-line index, or three fixed indices with Fire, RGB absorption tint and 1/4/8/16 AA taps. It finishes at the tap count without denoising. It omits polarization, birefringent doubling, scattering, zoning and edge rounding. Path-Traced retains the spectral model. Optical metrics, tilt sweeps and diagnostics keep their separate analytic tracer.