What this is for, and when to go and use something else.
There is no shortage of drawing programs, and some of them are very good at things this one does not attempt. A manual that pretends otherwise is not much use to somebody deciding whether to bother, so here is the honest version.
| If you want | Use |
|---|---|
| A building to build from | Revit, or FreeCAD's BIM workbench. |
| A part whose numbers you can go back and change | FreeCAD, SolveSpace, Dune 3D; Fusion or Onshape if you do not mind an account. |
| Flat 2D drafting that behaves like AutoCAD - layers, blocks, linetypes | LibreCAD, QCAD, ZCAD. |
| To open somebody's DXF or DWG | Any of those three. This program reads its own files and nothing else yet. |
| Electrical drawings that write their own cable list | ZCAD's electrical build - see below. |
| Rounded, filleted solids, on Linux | Plasticity. |
| To model with a pencil on a tablet | Shapr3D. |
| A first 3D print, in a browser | Tinkercad. |
| Characters, sculpting, pictures | Blender. |
Roughing something out at a real scale, quickly, and getting a drawing or a file out the other end. A duct transition, a run of pipe, a shed, a bracket, the shape of a room. Pick a scale, put the cursor on a point, type the size, and print it at true scale or export a DXF.
Two things make it worth choosing over the program most people would reach for. It runs on Linux, which SketchUp has never done. And the trade work is in the box - fittings from your own measurements, a pipe spool leg by leg, and the flat pattern to cut from sheet - rather than being an extension somebody sells you.
ZCAD is written in Free Pascal and Lazarus, as this is, has been going for years longer, and is worked on daily. The two hardly overlap, which is the useful thing to know: they are different tools that happen to share a language.
| Go to ZCAD for | Stay here for |
|---|---|
| Opening DXF (R12 to 2018) and DWG | A solid - ZCAD has 3D coordinates and faces, but no solids and no push/pull |
| Layers, blocks, linetypes, text styles, SHX and TTF fonts | Offset and a corner fillet; trim, extend and array are in neither |
| A DXF another CAD program treats as its own | A manual in English - theirs is in Russian, and unfinished |
| Electrical work: devices, cable routing, the cable legend, the materials list and a bill of materials, out as CSV and XLSX | Duct fittings, the pipe spool, flat patterns |
| An object inspector, and scripting in Pascal Script | STL for a printer, animated pictures |
| A Russian interface | A Linux download - their current release ships for Windows, and Linux is a build from source |
| Missing | Where to get it |
|---|---|
| Groups and components | Groups are built - see Groups. Components, a definition with copies that all change together, are not; a copy of a group here is a group of its own. |
| Reading other people's files | Its own format only. DXF import is planned, and last; DWG is not planned. LibreCAD, QCAD and ZCAD read both. |
| Layers | Groups organize by what a thing is; nothing here organizes by kind of line, or hides a kind. Every drafting program has layers and SketchUp has tags. |
| Solid union and intersection | A shape can be drilled through a solid and that is all. Plasticity, FreeCAD, SolveSpace, Dune 3D, Tinkercad and paid SketchUp do the rest. |
| Rounded edges in 3D | The arc tool fillets a flat corner. Plasticity and Shapr3D are built round doing it to a solid. |
| Hatching, linetypes, paper layouts | LibreCAD, QCAD, ZCAD. |
| Shadows and a perspective view | The light follows the camera, as SketchUp's does; shadows and a perspective camera for looking are planned. |
| Other languages | English only. LibreCAD is in over thirty. |
| Parametric history | Going back and changing a number afterwards: FreeCAD, SolveSpace, Dune 3D. A shape roughed out here exports to OpenSCAD, and can be made parametric there. |
| A plugin language | SketchUp's Ruby, FreeCAD's and Blender's Python, QCAD's JavaScript, ZCAD's Pascal Script. Here there is no API: the drawing is text - Heck, experimental - and a jig is any program that prints it, in whatever language is already on the machine. |
| Photo-real rendering | Not attempted, and not planned. |
| BIM, assemblies, FEA, CAM | Revit and FreeCAD. |
| A macOS build | The code should build on it; nobody has built it. |
| Here | What it means |
|---|---|
| One file | Eleven megabytes on Windows, twenty-one on Linux. No installer, no runtime, no account, nothing phoning home. The manual you are reading is inside it. |
| Linux, natively | And Windows. The same program, the same drawings. |
| SketchUp's habits | The same keys, the same typed measurements, the same push/pull, on purpose - so somebody who knows that program is not starting again. |
| The trade tools | Fittings, the pipe spool, and unfolding. |
| Exports | PNG, JPEG, animated WebP, SVG, DXF (view and model), STL, OpenSCAD, PDF. The animation encoder is inside the program; nothing extra is installed. |
| Commands you can type | / and a word - about eighty, all listed. The drafting programs have this; none of the push/pull ones do. |
| True scale on paper | Pick a scale and that is what the printer makes. Half the 3D programs in the table cannot print a drawing at all. |
| Reports that say what went | Encrypted on your machine before they leave, with a summary of exactly what was sent - see When it breaks. |
| The drawing as text | Heck, experimental: the sheet written one statement to a line, readable, editable both ways - and so a drawing under git, with a diff that says what moved and nothing else, and history and branches for free. None of the others has a readable native file. |
| MIT license | Fork it, sell it, mount it on a machine. That is the point. |