SKP archive members (SketchUp 2021 and later)

The ZIP archive holds the model as a set of files, its members. The pictures are PNG and JPEG, the materials and styles XML, and the model and its metadata trees of tagged values.

The members

Member	Contents
`meta/model_thumbnail.png`	The thumbnail, a PNG.
`meta/preview_thumbnail.png`	A second picture, a PNG.
`meta/meta.dat`	Metadata: the version, the units and the save history.
`materials/<name>/material.xml`	One material, in XML.
`materials/<name>/<image>`	The material’s texture image (JPEG seen).
`thumbnails/Component#N.png`	Component thumbnails.
`styles/<name>/style.xml`	A style, in XML.
`model.dat`	The model, a tree of tagged values. Always the last member.

The order seen is: the two pictures, meta.dat, the materials, the component thumbnails, the styles and model.dat. A SketchUp 2023 file had 65 members; the largest file seen, 693 MB, had 2,720, among them 1,361 material.xml files whose textures were about 520 KB each.

Thumbnails

meta/model_thumbnail.png is the model’s thumbnail and meta/preview_thumbnail.png a second picture of it, 256 × 256 pixels in the files seen. Both are PNG files kept as Deflate stored blocks, so their bytes can be read straight from the file. meta.dat names them both, with the image type 4, the same number the older files use for a PNG thumbnail.

meta.dat

A small tree of tagged values, 330 to 595 bytes once inflated in the files seen. It holds the version of the last save, the model’s units, a GUID, the names of the two pictures and the save history: every save of the model with the program, its version and the time. Its tags are listed on model.dat and meta.dat.

Materials

Each material has a folder under materials/ holding a material.xml and, if it is textured, the texture image. The folder name is the material name with characters such as < and > replaced by _, so the material <Glass Blue Tint> is in materials/_Glass Blue Tint_/; that rule is inferred from the names seen.

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<materialDocument xmlns="http://sketchup.google.com/schemas/sketchup/1.0/material" xmlns:mat="http://sketchup.google.com/schemas/sketchup/1.0/material">
  <mat:material name="&lt;Glass Blue Tint&gt;" type="2" workflow="0" colorRed="9" colorGreen="175" colorBlue="241" colorizeType="0" trans="0.52000000000000002" useTrans="1" hasTexture="1">
    <mat:texture textureFilename="C:\Program Files\@Last Software\SketchUp 3.0\Materials\\glass-tinted.jpg" xScale="24" yScale="24" avgColor="4293970184">
      <mat:images>
        <mat:image id="1" path="./glass-tinted.jpg" file_name="glass-tinted.jpg" />
      </mat:images>
    </mat:texture>
  </mat:material>
</materialDocument>

A material.xml from a 2023 file, as it is in the file

The attributes seen on mat:material:

Attribute	Example	Meaning
`name`	`<Glass Blue Tint>`	The material’s name, with XML escapes.
`type`	2	Not decoded here.
`workflow`	0	Not decoded here.
`colorRed`, `colorGreen`, `colorBlue`	9, 175, 241	The colour, 0 to 255 each.
`colorizeType`	0	Not decoded here.
`trans`	0.52000000000000002	Read by the explorer as the opacity, when `useTrans` is 1.
`useTrans`	1	Whether `trans` applies: 0 or 1.
`hasTexture`	1	1 when the material has a texture, given in the `mat:texture` element.

The mat:texture element gives the original path of the texture file, its scale and an average colour, and mat:image the image’s name in the material’s folder. The original path in the example still names SketchUp 3.0’s own materials folder, and the namespace URLs still name sketchup.google.com.

Some materials are named Layer_ and a tag’s name, such as Layer_A-Wall; that these hold the tags’ colours is an inference. The explorer lists every material with its colour, opacity and texture.

Component thumbnails

The members under thumbnails/, named Component#1.png, Component#2.png and so on, are PNG thumbnails of the model’s components. Which component each belongs to is not recorded here.

Styles

Each style is a style.xml in a folder under styles/. Every file seen has two, [Simple Style] and [Simple Style]_1. Their contents are not described here.

model.dat

The model itself: its geometry, components, tags, scenes and options, as one large tree of tagged values, always the last member of the archive. In the files seen it was 3.8 MB to 21.9 MB stored and 17.5 MB to 86.6 MB once inflated. Its layout, and what is known of its tags, is on model.dat and meta.dat.

.SKP File Format – Members