Is cncfoam.com free?
Yes — the simulator is free to use. The hardware is documented openly so you can build a machine from off-the-shelf parts. There are no ads in the tool.
Do I need an account?
No. You can design, simulate and download G-code without signing in. A free account adds saved projects, settings sync across devices, and the ability to publish/like/comment in the shape library.
Do I need to install anything?
No. The whole simulator runs in your browser. For USB streaming you need a Chromium-based browser (Chrome, Edge, Opera) that supports WebSerial.
What machines does it work with?
Any machine that accepts standard G-code. The reference setup is ESP32 + FluidNC (with USB and Wi-Fi streaming built in), but RAMPS/GRBL-style controllers work too since you can download the G-code and run it through your own sender or SD card. See Controllers.
What foam should I use?
EPS (white bead board) and XPS (coloured insulation board) are the best — cheap, clean and easy. EPP works for tough parts. Never hot-wire polyurethane (PU) or PVC foam — they release toxic fumes. See Foam materials guide.
What files can I load?
SVG and DXF outlines, and existing G-code (.gcode .nc .txt .cnc .tap .ngc .gcd). SVGs are auto-cleaned and sanitised on load. See Loading shapes.
Can it cut 3D shapes, or just flat profiles?
It cuts ruled surfaces — straight extrusions (2-axis), tapered/twisted morphs between two profiles (4-axis), and multi-sided parts built from rotated passes (3/5-axis indexed rotation). Doubly-curved 3D shapes are made by combining morphs with rotation. See How it works.
Why is my SVG not loading elsewhere?
CAD-exported SVGs often contain junk that breaks parsers. Run it through the SVG cleaner (or just load it into cncfoam.com, which cleans automatically). See The SVG cleaner.
Are the USB/Wi-Fi streamers safe to rely on?
They work, but carry a BETA badge until fully verified against production hardware. For critical jobs, download the G-code and use your trusted sender. Always keep a way to cut power within reach.
How accurate are the cut-time estimates?
They are computed from contour length and feedrate with a small corner allowance — a good guide, but real time varies with acceleration limits and how your machine handles corners.