Knowledge base

Hot-wire foam cutting answers

A searchable, curated library of answers on foam cutting, machine setup, G-code, FluidNC/GRBL and the free cncfoam.com tool. Most questions are already answered below — search or browse by topic.

Category: All General ✨ AI helper Building / DIY Hardware Electronics G-code Cutting tips Materials / foams Software / tool My setup

Browse answers by topic below, or use search. New to the tool? See how cncfoam.com compares to GMFC, DevFoam & JediCut, or read the hot-wire foam cutting wiki.

Category Software / tool · 25 matches. Clear filters.

📌 Can I cut a 3D model (STL or OBJ) on a hot-wire machine?

Yes — cncfoam.com can import an .stl or .obj and work out a cut automatically. Open ＋ Load parts → Import STL / OBJ. The important thing to understand: a hot wire only ma…
📌 My Inkscape SVG won't load in the tool — what gives?

Almost always one cause: your SVG was originally a DXF that you opened in Inkscape and re-saved as SVG. Inkscape's DXF importer leaves a pile of junk in the block — most…
How do I load an SVG or DXF into cncfoam.com?

Open the tool, click ＋ Load parts, and pick your file as Profile A (SVG, DXF, or G-code). The tool samples the outline into a cut path and drops it into the workspace, wh…
How do I morph between two different profiles?

In ＋ Load parts, choose the Two-part morph option, then load Profile A (left end) and Profile B (right end). The tool blends the two outlines linearly along the span and…
How do I export an STL of my cut?

Load or generate a shape, then open the Download / stream menu and click 3D (STL). You get a file (cncfoam_result.stl) of the carved 3D solid — the actual shape the wire…
How do I stream a job to my machine from the browser?

Open the Download / stream menu and pick USB or Wi-Fi. For USB, use a Chromium browser (Chrome/Edge/Opera/Arc/Brave — Firefox/Safari lack WebSerial), plug in the ESP32, c…
My imported model came out blobby / lost its detail — is it broken?

Almost always one of two things, and neither is a bug: 1. Wrong rotation axis. Spin the model around its longest, most-detailed axis. The import pop-up now recommends one…
Which rotation axis should I choose — vertical or horizontal?

Spin the model around its longest axis: - Vertical (around Y) — for upright shapes that are taller than they are deep: busts, bottles, columns, trees, chess pieces. - Hor…
What do the Rotate part (X/Y/Z ±90°) buttons in the status panel do?

They spin an imported STL/OBJ's starting orientation in exact 90° steps about each axis, then re-slice and rebuild the cut automatically so the preview updates right away…
How many cut angles should I use for a 3D model?

12 is plenty for almost everything. The visual hull tightens quickly for the first dozen silhouettes and then barely changes — past about 24–36 you're adding real-world c…
My cut parts come out a fraction undersized — how do I fix that?

That's kerf — the hot wire melts a channel slightly wider than the wire itself, so the path removes a little material on each side and the part ends up undersized (and ho…
What exactly does the SVG cleaner strip out?

Six things, all leftovers from Inkscape / DXF imports that no part of a valid foam-cutter shape ever needs: 1. — DXF Model_Space / Paper_Space placeholders. The * makes t…
Is the cleaner safe to run on a file I already know works?

Yes — designed for it. If the file has nothing to strip, the cleaner passes it through unchanged (or near-unchanged: only whitespace differences from re-serialisation). T…
My SVG looks fine in Inkscape but the tool shows nothing — why?

Most common causes: 1. The SVG uses / / primitives that were NOT converted to paths. In Inkscape: select all → Path → Object to Path → save. 2. The SVG uses gradients / p…
Tool crashed mid-job during streaming — now what?

If you were streaming via USB / Wi-Fi and the connection dropped, the controller may have stopped mid-cut. Worst case: the wire stayed hot in one position and melted a di…
How do I export a shape as a 3D model (STL, OBJ) instead of G-code?

Not supported — the tool is purpose-built for hot-wire cut paths, not general 3D solids. The lofted morph you see in the simulator is reconstructed from cut geometry at r…
Why is the tool so dark? Can I switch to a light theme?

Dark is the only theme right now — the cut ribbon's colour-coded vertex shading and the WebGL grid both look best on dark backgrounds, and most hobby CAD/CAM tools are da…
Which file formats can I upload to the shape library?

Three source formats: SVG, DXF, and G-code (.gcode, .nc, .txt). .nc and .txt files are sniffed for G-code content and rejected if they don't look right (e.g. plain text).…
Why does my DXF load with extra junk geometry?

DXF is a hairy format and CAD tools export wildly different subsets. Our parser handles: LINE, LWPOLYLINE, POLYLINE, CIRCLE, ARC, SPLINE (via de Boor sampling). Hatching,…
Can two people work on the same job at the same time?

Not in real-time — shared sessions are on the roadmap ("two users on the same job for remote teaching") but not built. Today you can collaborate async: one person publish…
Does the tool work behind a corporate firewall?

Probably. The tool fetches Three.js from cdnjs.cloudflare.com at first load — that domain needs to be reachable. After that everything is local in the browser. Streaming…
How do I get the tool to remember my cutter size?

Sign in, then any Settings change auto-syncs to your profile (debounced ~1s after the last edit). Next time you load the tool on any device while signed in, your settings…
Can I save a job and reload it later without re-doing all the transforms?

Yes — signed-in only. Click 💾 Projects (top header), name your job, save. The CURRENT cut + all CFG settings + all OBJECT-bar transforms get serialised together. Load lat…
Can I edit the G-code directly inside the tool?

Not yet — the G-code viewer (Settings → Tool interface → G-code viewer) shows the generated G-code colour-coded, but it's read-only. You can download the G-code, edit in…
Why does my browser say \"the tool is using a lot of memory\"?

Three.js scenes are GPU-heavy and the cut ribbon grows as the simulation plays. Memory use is normal up to ~500MB on a 2000-line job. If your browser tab is using 2GB+, t…

Can't find your answer? Ask

Missing something? Send it in and it gets answered and added to this library.

Create a free account or sign in to ask.