Working with Files

Part files

Parts are saved as .rcad files, assemblies as .rasm, drawings as .rdrw and drawing templates as .rdrt files (see the Assemblies and Drawings chapters).

Tabs and closing

Several parts and drawings can be open at once, each in its own tab. New, Open and Sample all open a new tab. Closing a tab with unsaved changes asks whether to save it, and closing RazorCAD asks to save every unsaved part.

Auto-save and recovery

Auto-save starts once a part has been saved for the first time. While the part has unsaved changes it is written next to the part file, at most every 20 seconds, as Name.autosave.rcad. The title bar shows the time of the last auto-save. Saving the part removes the auto-save file.

If RazorCAD closes with unsaved changes, opening the part again offers to recover the auto-saved version. It is also marked in the recent list.

The recent-files list is kept in %APPDATA%\RazorCAD\recent.json.

Opening from Windows and file previews

Double-clicking a .rcad, .rasm or .rdrw file opens it in RazorCAD; if RazorCAD is already running, the file opens in a new tab there. RazorCAD sets the file types up itself when it starts. Help ▸ Open Files With RazorCAD… shows whether they are registered and can register them again.

Saving keeps a small picture of the view in the file. Windows Explorer, the Open and Save dialogs and the start window show it as the file's thumbnail.

A part that takes a while to build is stored, once built, in %LOCALAPPDATA%\RazorCAD\modelcache (kept under 1 GB). With it the kernel keeps the geometry after each feature. Opening the unchanged file again shows the model at once, ready to edit: the first change after opening rebuilds only from the changed feature on, as any later change does. Switching tabs also shows each part at once.

Importing STEP, STL, OBJ and 3MF

There are two ways to bring in a STEP, STL, OBJ or 3MF file:

• File ▸ Open… opens it as a part of its own in a new tab, named after the file, without asking. A STEP file that holds an assembly asks first:
  • Open as an Assembly makes a new assembly with the file's structure: a sub-assembly for each of its sub-assemblies, a part for each part, and a component, fixed, where the file places each one. Each part keeps its own piece of the STEP file and is built on its own, and a part used several times is built once.
  • The first build of each part is kept on disk (in %LOCALAPPDATA%\RazorCAD\modelcache, up to 1 GB, shared with parts). The next time the assembly opens, unchanged parts are shown straight from there instead of being rebuilt, so a big assembly reopens in seconds.
  • Open as One Part brings every solid into one part, as before.
• File ▸ Import STEP / STL… (Ctrl+I, also on the Features tab, and Import STEP / STL / OBJ / 3MF on the Evaluate tab) offers three choices: a new part, insert in place into the current part, or insert and locate with mates. Locating with mates adds a separate "Locate …" Move Body feature under the import.

How imports behave:

• The file's contents are stored inside the part file, so the part does not depend on the original file.
• A STEP file's appearances come with it: the colour of each solid and of single faces, and transparency. Your own Appearance and Make Transparent / Make Opaque settings on a body win over them.
• STEP imports as an exact solid. Every solid becomes its own body; a solid made of several separate shells is split into one body per shell; loose surfaces become surface bodies.
• The bodies of a multi-body STEP file are grouped in their own folder under Solid Bodies.
• Tick Merge touching bodies into one body in the import feature to fuse them instead.
• STL, OBJ and 3MF meshes are converted to a solid made of their triangles, with coplanar triangles merged. A 3MF file's units and build placement are read. A mesh that is not closed comes in as a surface body, with a note saying how many open edges it has; Repair Mesh or Convert to Solid (Surfaces chapter) can close it.
• Big meshes are simplified on import, by default to 80,000 triangles, keeping their edges and outlines. Set the limit in the import's properties (Simplify meshes above … triangles; 0 never simplifies). The import's note says how far a mesh was simplified.
• Imported bodies can be cut, extended, patterned and (for STEP) filleted like any other body. A cut or fillet on a body of more than 20,000 mesh faces warns that it can take several minutes.

IGES files can't be read: the geometry kernel is built without IGES. Use STEP, which every CAD program writes.

Exporting

Export Face as DXF

Click a flat face, then right-click ▸ Export Face as DXF… (or File ▸ Export ▸ Face as DXF…). The face's outline (layer OUTLINE) and holes (layer HOLES) are written as a 2D drawing in millimetres, seen from outside the part. Use it for laser or waterjet cutting, or to take a profile into a 2D CAD program.

Lines, arcs and circles are exact; other curves become fine polylines. The file is DXF R12, which practically every program can read.