The major changes in Substance 3D Sampler 4.2 include an updated version of Image to Material, a system for generating PBR texture maps from a single source image, trained by artificial intelligence. This new version has been "trained on all material types," and users can now choose specific algorithms tailored to a range of common materials. These materials include asphalt, leather, metal, paint, paper, plastic, rubber, as well as stone and general categories for organic and soil materials, as demonstrated in the video above. According to Adobe, the new algorithms provide better results when working with many materials. The release notes specifically highlight fabric, plaster, and wood.
Additionally, the update introduces a completely new AI-trained feature called Upscale. As the name suggests, it increases the resolution of textures, working with the base color, normals, height, roughness, and metallic material channels, with the AI filling in missing details. Texture resolution can be increased by 2 or 4 times, although an option to reach a specific target resolution is not currently provided.

The update also adds a new parameter that allows users to enable or disable GPU-accelerated neural networks, presumably for performance control when working with the new AI features.
Among other changes, there's a new layer resolution system where layers inherit the resolution of the document or the layer below. The user interface displays the dimensions of each layer in pixels, making it visually clear how edits affect the material's resolution.
In addition, the Crop filter now supports dynamic output resolution, and the Delighter filter, which removes baked shadows and lighting from source photos, has been "significantly improved," although the release notes do not specify exactly what has been changed.

Substance 3D Sampler 4.2 is available for Windows 10 and above, CentOS 7.0/Ubuntu 20.04 and above for Linux, and macOS 11.0 and above. The cost of new perpetual licenses available through Steam is $149.99. The Windows and macOS versions are also available through Adobe's Substance 3D Texturing subscription for $19.99 per month or $219.88 per year, as well as through the Substance 3D Collection subscription for $49.99 per month or $549.88 per year. The Linux release is available through Creative Cloud for Teams for $1199.88 per year.