Bitmap (Resource)


A bitmap resource is a resource in a Substance Package. It is different from the atomic bitmap node. The atomic Bitmap node is a specific representation of that bitmap inside a Substance graph

Bitmaps are some of the most common non-Graph resources in Substance Designer, usually their usage falls in one of the following categories:

  • A baked map, either baked internally by Designer, or externally by another application.
  • A helper texture, like a pattern, grunge map or decal.
  • A simple grayscale mask for blending, either created internally using the bitmap node, or with an external app.


Bitmap Storage

Bitmaps are usually the largest resource that Substance Designer deals with. That's why it's good you understand how Designer handles these files with its two main filetypes.

In SBS Files 

How bitmaps are stored in SBS depends on if you Link or Import them, make sure you are familiar with the concept first. Imported bitmaps can be edited using the Bitmap painting tools.

Unlike SVG (Vector Graphics) Resources, Bitmaps are always stored externally, even when created as a new resource, or imported. For new Substance Packages, they are kept in memory, until the .SBS file is saved to disk. Once saved to disk, bitmaps are stored in a /resources folder next to the SBS file.

In SBSAR Files

In SBSAR files, Bitmaps are embedded, meaning they have a large impact on the final SBSAR filesize. You can read more about the impact on filesize further on this page. When SBSAR files are published, only bitmaps that are used to compute an output of a graph are embedded. Any unused bitmaps are optimized and excluded from the final SBSAR package, with no effect on the filesize.

File Type, Color Mode and Resolution

Substance Designer can easily edit and re-arrange data from bitmaps, but it is best to keep the following in mind:

  • Set your resolutions to be power of 2 compliant, that means follow standard realtime texture size like 256, 512, 1024 ,2048, etc. Substance Designer will rescale textures outside of this range to the closest matching resolution. Note that they don't have to be in square proportions.
  • Many filetypes are supported, but choose one that is best for your usecase. Lossless compression or even uncompressed filetypes like PNG or TGA give better quality than JPG or DDS.
  • Make sure to set up your color mode correctly, depending on whether you need color, grayscale or an alpha channel. 

Bitmap Attributes

Bitmap Resources in a package have a number of attributes that you can customize. Most attributes don't have a major purpose and are for library filters, though a minority affects filesize..

Attribute namePurpose
Identifierused for referencing inside packages. No reason to change this
File PathUsed to reference file on disk in SBS. Do not modify directly, used Relocate... functionality!
DescriptionUsed for library descriptions.
CategoryUsed for Library filters.
LabelUsed for Library filters.
AuthorUsed for Library filters.
Author URLUsed for Library filters.
TagsUsed for Library filters.
User DataOptional extra data, not used on bitmaps.
Show In LibraryDetermines if bitmap should be hidden in the Library View.
Bitmap FormatEither Raw or Jpeg, has great effect on SBSAR filesize. See further
Bitmap Compression QualityOnly has an affect with Jpeg compression, determines quality/filesize balance.

Filesize Reduction

In some cases the total filesize of Substance Archives (SBSAR) can be an important factor. This page covers a few critical areas and settings to keep in mind when trying to reduce SBSAR filesize.

Filesize is mostly determined by embedded bitmaps. They are files that are linked, embedded or baked and added to the Substance package (SBS) as a resource. Only bitmaps that are used in a graph i.e. connected to an output either directly or through the node chain are published with the Substance material. In an SBS file, bitmaps have no impact on filesize, as all bitmap resources are still stored outside of the SBS file.


Filesize Factors

There are a few different factors affecting total filesize of the SBSAR. They are listed below with an short explanation.

  • Resolution
    Obviously has a large effect. Use the smallest resolution possible, keeping mind that you might also want your Substance file to work in large resolutions. You can use standard resolution-masking tricks to make smaller Bitmaps seem larger.
    Found in: external software, or import/re-export bitmap in Designer.
  • File Color Mode
    Set in your Image Editor before export, the color mode also has an effect on filesize when using Raw bitmap format. Grayscale only bitmaps are smaller than RGB(A) images.
    Found in: external software, or import/re-export bitmap in Designer while setting up Output nodes correctly.
  • Filetype
    The filetype of your images makes a difference, though it can be ignored in some cases. A program like Photoshop allows for slightly more control over JPG compression and can sometimes offer a decent middle road.
    Found in: external software, or import/re-export bitmap in Designer.
  • Usage in Graph
    What mode you set the Bitmap node to also has an effect on how Designer will compress the file, using a Grayscale mode file as a color bitmap in the graph will result in larger files. Make sure to set these correctly!
    Found in: Bitmap Node properties.
  • Bitmap Format in Package
    On the Resource properties you can choose between "Raw" and "Jpeg" compression. This can have considerable effect on the final result.
    Found in: Bitmap Resource Properties, through Explorer window.
  • Bitmap Compression Quality in Package
    When using "Jpeg" Bitmap format, the slider below can affect quality and filesize. This slider does not behave very predictable, but 1 tends to correspond to the highest quality JPG compression, and 0.5 tends to give the smallest size.
    Found in: Bitmap Resource Properties, through Explorer window.
  • Compression Mode on Publish
    When publishing to SBSAR, you have a choice between "Auto", "Best" and "None" for compressing, these can make a considerable difference if you are using the "Raw" bitmap format. Also has a large impact on export speed. Generally not recommended to use "none as it offers no quality increase.
    Found in: final publishing settings for an SBSAR package.

Filesize Comparison

The table below shows the influence of all settings on each other. Bitmap used is a 4096x4096 image of generated noise, exported from Photoshop as either 24-bit TGA or JPG at quality 8. TGA's were also exported as Grayscale and RGBA mode.

The Graph just places a single Bitmap Node connected to a single output. Bitmap mode is set according to source file mode.

Source Image =>Color TGAColor JPGGrayscale TGAGrayscale JPG

Raw Bitmap Format
None Compression Mode

48 MB48 MB16 MB16 MB
Raw Bitmap Format
Best Compression Mode
9.11 MB3.37 MB5.06 MB4.75 MB
Jpeg Bitmap Format
Compression Quality 1
5.09 MB1.94 MB6.30 MB2.49 MB
Jpeg Bitmap Format
Compression Quality 0.5
231 KB230 KB626 KB569 KB
Jpeg Bitmap Format
Compression Quality 0
407 KB433 KB990 KB808 KB

While the above table is not fully conclusive, the following can be learned when comparing visual results and file sizes:

  • Raw Bitmap + Compression Best gives the best quality with an acceptable filesize.
  • Pre-compressed source files can give reduced filesizes in most cases, but at a quality cost.
  • Smallest filesizes, but worst quality is obtained with JPG package format at quality 0.5.
  • Grayscale is not always smaller in filesize, but will have higher quality than color at similar settings.


Jpeg Bitmap Format

It's important to note that special maps that require high accuracy such as Normal maps, Vector Maps and others should probably not be set to Jpeg compression, as this will lead to much more visible artifacts!