Does anyone using the NVidia Photoshop plugin have any advice on the best format for saving .dds textures?

I am modifying EA and custom textures and I'm finding any save I make gets a lot of lossy type artefacts, which was not the case before I updated to the latest version of Photoshop.

I'm saving as "bc3" and highest quality, but still there are artefacts. How do others here save their custom .dds
images?

That highly depends on what you are using it for.

The .dds-formats I use mostly for CAW textures like terrain paints and road textures are

- DXT1 RGB no alpha for textures without alpha channel
- DXT5 ARGB 8bpp interpolated alpha for the rest.

If in doubt, you can check the .dds-format of the original texture, the one you want to replace, or a texture from a comparable use with Windows Texture viewer (if you are using windows). You can find that tool on the NVIDIA site: https://developer.nvidia.com/legacy-texture-tools

If you have the correct plugins, S3PE also can display that information.

The other thing to consider is mipmaps. Those usually are required.

Also make sure that you stick to the size ratio. Textures need to be multiples of 4, usually starting at 256x256 or bigger like 512x512 or 1024x1024.

Here is a guide for textures that also explains .dds-textures, maybe that helps, too: https://blog.thesimsresource.com/si...textures-guide/

Sometimes Photoshop plugin exports with horrible artifacts, especially on the Red and Blue channels, more obvious when you have gradients and small details.
When that happens, I save my image as PNG or TIFF first. (TIFF is useful when making a control map/mask since it keeps all layers intact for sure regardless of alpha channel contents)
Then I switch to the standalone version of NVIDIA Texture Tools Exporter and import my image in there. Select "Highest" in the Compression Effort options. Format is BC3 if you need DXT5, BC1 if you need DXT1.
Saving from that tool gives me much much better results, even keeping smooth gradients mostly intact.

Thanks Slamyy and Norn - much useful info! I will try your suggestion Slamyy

Does anyone use PNGs in place of or as well as dds?

No, TS3 does not support using them interchangeably like TS4 does.
_IMG resources can be either, but you need to use whatever the original was or it will not display correctly ingame. The majority of textures will be DDS, while things like icons and UI images are PNG.

It's possible to use uncompressed DDS, if the compression effects are the limiting factor for you- but the file size will suffer significantly, and the size of textures more or less represents how much RAM they will require (a finite resource for this game and its memory problems). Used sparingly, still very useful.
The mipmaps included with DDS are generally more important than any other benefits that other formats provide.