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+# AnyCubic Photon S - PWS File Format
+
+## Introduction
+
+AnyCubic introduced a new PWS File Format with printer firmware version P_V341 and slicing software Photon_WorkShop_V2.0.23 in early August 2019.
+This document records the results of trying to reverse engineer the new file format.
+
+## File Structure
+
+The binary file seems to be divided into five sections FileHeader, Header, Preview, LayerDef each marked with a magic text value; and then the RLE encoded layer image data.
+
+The text values used for section magics could be 12 bytes with zero byte padding, or 8 bytes with zero padded and a zero 4 byte value.
+Integer and Float values have little-endian byte order.
+
+Note: Fields with unknown usage are named and numbered from the offset in bytes from the beginning of the section magic value.
+
+| Name | Length | Type | Value from  R_E_R_F.pws | Note |
+| --- | --- | --- | --- | --- |
+| FileHeaderMagic | 12 | Text | ANYCUBIC | |
+| FileHeaderUnknown12 | 4 | Unknown | 0x01000000 | |
+| FileHeaderUnknown16 | 4 | Unknown | 0x04000000 | |
+| FileHeaderUnknown20 | 4 | Unknown | 0x30000000 | |
+| FileHeaderUnknown24 | 4 | Unknown | 0x00000000 | |
+| FileHeaderUnknown28 | 4 | Unknown | 0x90000000 | |
+| FileHeaderUnknown32 | 4 | Unknown | 0x00000000 | |
+| FileHeaderUnknown36 | 4 | Int | 0xac260100 | Layerdef file position.|
+| FileHeaderUnknown40 | 4 | Unknown | 0x00000000 | |
+| FileHeaderUnknown44 | 4 | Int | 0xc04a0100 | LayerImage file position. |
+| HeaderMagic | 12 | Text | HEADER | |
+| HeaderLength | 4 | Int | 80 | |
+| HeaderUnknown16 | 4 | Float | 0x00003d42, 47.25 | Pixel size? |
+| HeaderUnknown20 | 4 | Float | 0xcdcc4c3d, 0.05 | Layer height? |
+| HeaderUnknown24 | 4 | Float | 0x00008040, 4.0 | |
+| HeaderUnknown28 | 4 | Float | 0x0000803f, 1.0 | |
+| HeaderUnknown32 | 4 | Float | 0x00007042, 60.0 | |
+| HeaderUnknown36 | 4 | Float | 0x00004040, 3.0 | |
+| HeaderUnknown40 | 4 | Float | 0x0000c040, 6.0 | |
+| HeaderUnknown44 | 4 | Float | 0x00004040, 3.0 | |
+| HeaderUnknown48 | 4 | Float | 0x00004040, 3.0 | |
+| HeaderUnknown52 | 4 | Unknown | 0x531bac41 | |
+| HeaderUnknown56 | 4 | Unknown | 0x01000000 | |
+| HeaderLayerX | 4 | Int | 1440 | |
+| HeaderLayerY | 4 | Int | 2560 | |
+| HeaderUnknown68 | 4 | Unknown | 0x531bac41 | |
+| HeaderUnknown72 | 4 | Unknown | 0x531bac41 | |
+| HeaderUnknown76 | 4 | Unknown | 0x00000000 | |
+| HeaderUnknown80 | 4 | Unknown | 0x00000000 | |
+| HeaderUnknown84 | 4 | Unknown | 0x00000000 | |
+| HeaderUnknown88 | 4 | Unknown | 0x00000000 | |
+| HeaderUnknown92 | 4 | Unknown | 0x00000000 | |
+| PreviewMagic | 12 | Text | PREVIEW | |
+| PreviewLength | 4 | Int | 75276 | |
+| PreviewWidth | 4 | Int | 224 | |
+| PreviewUnknown20 | 4 | Unknown | 0x2a000000 | |
+| PreviewHeight | 4 | Int | 168 | |
+| PreviewImage | PreviewWidth * PreviewHeight * 2 | Image | | 16-bit RGB565 or RGB555 color image. |
+| LayerdefMagic | 12 | Text | LAYERDEF | |
+| LayerdefLength | 4 | Int | 9220 | |
+| LayerdefCount | 4 | Int | 288 | |
+| Layerdef | LayerdefCount * 32 | Binary | 0xc04a01005c8900000000c0400000404000007042000000000000000000000000 0x1cd401005c8900000000c0400000404000007042000000000000000000000000 ... | TODO |
+| LayerImages | Variable | Binary | 0x7d7d7d7d7d7d7d7d7d7d7d7d7d7d7d7d ... | Bit-level RLE (0x7d gives 125 zero bits and 0xfd gives 125 one bits).   Decode HeaderLayerX bits to produce a layer image line then repeat HeaderLayerY times to produce a 2-bit layer image. |
+
+### Layerdef
+
+| Name | Length | Type | Value from  R_E_R_F.pws first layer | Note |
+| --- | --- | --- | --- | --- |
+| LayerdefUnknown0 | 4 | Int | 0xc04a0100 | Layer file position. |
+| LayerdefUnknown4 | 4 | Int | 0x5c890000 | Layer length|
+| LayerdefUnknown8 | 4 | Float | 0x0000c040, 6.0 | |
+| LayerdefUnknown12 | 4 | Float | 0x00004040, 3.0 | |
+| LayerdefUnknown16 | 4 | Float | 0x00007042, 60.0 | |
+| LayerdefUnknown20 | 4 | Unknown | 0x00000000 | |
+| LayerdefUnknown24 | 4 | Unknown | 0x00000000 | |
+| LayerdefUnknown28 | 4 | Unknown | 0x00000000 | |
+
+## Tools Used
+
+AnyCubic has only released Windows and Mac builds of it's new slicer, and the Windows build of Photon_WorkShop_V2.0.23 crashes when trying to use it with Wine on Linux.
+Vim and bvi were used for some initial exploration of the R_E_R_F.pws file.
+The trial version of [Hexinator](https://hexinator.com/) helped with identifying some of the interdependency between sections.
+A simple Java program was written to dump the file contents and extract preview and layer images.
+
+## TODO
+
+* Get more sample pws files with known settings.
+* Reverse engineer Layerdef values.
+* Maybe release Java dump tool.
+
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