• Syntax highlighting
• Basic completion function (press M-TAB)
• Preview rendered model in separate window (press C-c C-c)
• Open buffer in OpenSCAD (press C-c C-o)
• Export buffer with OpenSCAD (press C-c C-e)
• Flymake support (enable flymake-mode in scad-mode buffers)
• Org Babel support (scad source blocks)

for (y=[0:2:20]) {
    translate([0,0,y+1])
        cube([30-2*y,30-2*y,2], true);
}

Install via M-x package-install RET scad-mode RET from NonGNU ELPA or MELPA. After the installation *.scad files will be opened with scad-mode.

• scad-dbus: Interact with a running OpenSCAD instance from Emacs via DBUS
• lsp-mode, eglot or lsp-bridge: The openscad-lsp server can be used with scad-mode