CIF to GDS converter
CIF-to-GDSII conversion moves a layout from Caltech Intermediate Form into the format almost every mask shop and design tool actually expects. Both describe a hierarchy of cells (CIF calls a cell a symbol) holding polygons, wires and labels on numbered layers, so the conversion mostly re-encodes rather than re-models. This CIF to GDS converter runs entirely inside your browser — the file is read, converted and written locally, and there is no server to upload it to.
How to convert CIF to GDSII
- Drop your
.ciffile onto the converter on this page — including a CleWin structure library. - Pick GDSII as the target format.
- Download the
.gdsfile. Open it in the free Glyph editor if you want to inspect cells, layers or hierarchy before handing it on.
What survives and what changes
| Aspect | What happens |
|---|---|
| Hierarchy | Preserved. A CIF symbol becomes a GDS structure and a C call becomes an SREF; nothing is flattened for an ordinary, unmagnified placement. |
| Magnified references | None in CIF: a call carries mirror, rotation and translation but no scale, so every call becomes a plain GDS reference (magnification 1). |
| Widened wires | Kept as GDS paths of the same width, with half-width extended ends as KLayout reads a bare CIF wire (a 98 end-style hint in the file sets flush or round instead). A zero-width wire stays a zero-width GDS path. |
| Layers | L{layer}D{datatype} maps directly onto the GDS (layer, datatype) pair — no invented convention needed, unlike a format with no datatype concept. |
| Large arrays | CIF has no array primitive, so a symbol called in a dense repeating pattern converts to individual placements rather than a single GDS AREF. |
| Units | CIF's base unit is 0.01 µm; every coordinate lands as a whole number of nanometres, rounded where a DS scale makes a fraction. |
| Text | A CIF 94 label carries only a string and a position — GDSII text carries the same, so nothing is lost that CIF had in the first place. |
| CleWin libraries | Parameter declarations and generating script text stored in CIF comments are read (read-only, never executed) but have no GDSII home, so only the resulting geometry is written. |
| Other properties | Layer colour, stipple and visibility have no GDSII layer-appearance record and are not carried over. |
CleWin CIF files specifically
A CleWin structure library is a CIF file whose symbols carry parameter declarations and generating script text inside CIF comments. This converter's reader decodes them the same way the full Glyph editor's Properties panel does — read-only, Glyph never executes the script — so the geometry converts correctly even though the parameter record itself has nowhere to go in GDSII. See CleWin alternative for the full picture of what that support does and doesn't cover.
Why CIF and GDSII both exist
CIF — Caltech Intermediate Form — is an older, plain-text, human-readable layout format that predates GDSII's binary record structure and is still the native format CleWin's structure libraries ship in. GDSII is the binary format almost every mask shop and downstream tool expects today. Converting from CIF is usually the first step in getting a design out of an older or niche tool and into a mainstream flow.
For the destination format's record structure, see the GDSII file format reference, and for the vocabulary, the mask layout glossary. If you need a target other than GDSII, the CIF converter also writes OASIS, DXF and SVG.
Open it in the editor
To check cells, layers and hierarchy after converting, open the file in the free Glyph editor — nothing to install, and your files never leave your browser. See Cells & hierarchy and Layers.
Glyph is made by NANYTE. For where a finished layout goes next, read NANYTE's maskless lithography overview.
Frequently asked questions
Does this reader understand CleWin's CIF dialect?
Yes. A CleWin structure library carries each symbol's declared parameters and its source script inside CIF comments, plus layer colours. The reader picks all of that up; opening the same file in the full Glyph editor also shows the read-only parameter record. The script itself is never executed, only stored.
What happens to a widened CIF wire?
It becomes a GDS path of the same width. A bare CIF wire gets half-width extended ends, the way KLayout reads one; when the file carries KLayout's 98 end-style hint before the wire (flush or round), that style is used instead. A zero-width wire stays a zero-width GDS path — a centreline.
What happens to a magnified CIF reference?
CIF has none to convert. A CIF call carries mirror, rotation and translation but no scale, and CIF's own DS symbol scale only affects a symbol's own coordinates, not the geometry of symbols it calls — so every call becomes a GDS reference with magnification 1. Going the other way, a magnified GDS reference is flattened when it is written as CIF, because CIF cannot express it.
What units does the converted GDSII file use?
Integer world nanometres. CIF's base unit is 0.01 µm (10 nm), so at the default scale one CIF unit converts to exactly 10 nm. Where a symbol's DS scale makes a coordinate that is not a whole nanometre (KLayout writes a 0.5 nm layout as DS n 1 20), it is rounded to the nearest nanometre, as KLayout reads it at its default 1 nm unit.
Do layer and datatype both survive?
Yes. CIF names a layer L{layer}D{datatype}, so the pair carries straight across and a 1/0 layer can never merge with a 1/4 layer the way a format with no datatype concept would risk.
Is there a file size limit?
The conversion runs inside your browser tab, so your machine's memory is the real ceiling. The converter checks the file size before parsing, warns above roughly 50 MB and declines files beyond roughly 200 MB rather than risking an out-of-memory crash.
Is my CIF file uploaded anywhere?
No. The conversion runs entirely in your browser using the same reader as the Glyph editor. There is no server to upload to, and your design data never leaves your machine.