OASIS Converter
Convert an OASIS (.oas/.oasis) layout to GDSII, DXF, CIF or SVG — free, online, entirely inside your browser. OASIS (SEMI P39) is a specialist semiconductor mask format, and most general file-conversion sites don't support it at all; this converter uses the same reader that backs Glyph's own File → Open, so cells, placements, and all twelve OASIS repetition types are handled properly rather than approximated.
Where an OASIS file can go
| Target | What you get |
|---|---|
| GDSII | Lossless for the hierarchical model — a CELL becomes a GDS structure, a PLACEMENT becomes an SREF or AREF. One of the cleanest conversions in mask work. |
| DXF | Cells and placements map to blocks and inserts the same way as GDSII; DXF's layer table gains a (layer, datatype) naming convention since DXF has no datatype field of its own. |
| CIF | Same hierarchy mapping; magnified placements flatten, since a CIF call carries no scale. |
| SVG | A flattened vector image — SREF/AREF are expanded, colour is kept, the original layer number is not. |
How to convert an OASIS file
- Drop your
.oasor.oasisfile onto the converter above. Compressed (CBLOCK) files need no special handling. - Pick the target format — GDSII, DXF, CIF, SVG, EPS or PNG.
- Download the result. Nothing is uploaded to a server first.
Why OASIS needs a real reader, not a generic one
OASIS packs the same geometry as GDSII into a much smaller file using variable-length integers, built-in repetition descriptions, and modal state that lets a writer omit unchanged values between records. A converter that doesn't decode that modal state correctly produces geometry in the wrong place with no visible error. Glyph's OASIS reader is checked against KLayout and gdstk on every release, and reports a malformed file (a modal field a record needed but the file never set) rather than silently carrying over an unrelated value.
For the full comparison between the two formats — file size, compression, adoption — see GDSII vs OASIS. For the full pairwise matrix across every format Glyph handles, see the Glyph File Converter hub.
Honest limits
- A round-capped path exports to GDSII with a squared cap — OASIS has no round-cap primitive, and this converter doesn't invent one going the other way either.
- There's a file-size ceiling (~50 MB warn, ~200 MB refuse). Open large layouts in the full Glyph editor instead.
- Irregular (non-uniform) repetitions are capped at 250,000 instances per repetition and 2,000,000 elements per file, with truncation reported, never silent.
Frequently asked questions
Is there a free online OASIS converter that actually works?
Yes — this one. It runs the same OASIS reader that backs the Glyph editor's File → Open, entirely in your browser, so it isn't a generic file-conversion site guessing at a semiconductor format it was never built to handle.
Does this OASIS converter support compressed files?
Yes. CBLOCK-compressed OASIS files are read; the compressed blocks are flattened transparently as the record stream is walked, so a compressed file converts exactly like an uncompressed one.
Do OASIS repetitions (arrays) survive conversion to GDSII?
All twelve repetition types are read. The five regular forms collapse to a single GDS AREF (constant memory, however large the array); irregular forms expand to individual elements, capped and reported if the file is unusually large.
Is my OASIS 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.
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.
Need to inspect it first?
Open the file in the free Glyph editor instead of just converting it — same OASIS reader, plus the canvas, layer tooling and a geometric design-rule check. See Cells & hierarchy for how OASIS placements appear once opened.
Glyph is made by NANYTE. For where a finished layout goes next, read NANYTE's maskless lithography overview.