CoplayDev/unity-mcp · error · ArgumentException

Width should be larger than 0

Error message

Width should be larger than 0

What it means

Thrown by CustomPreviewGenerator.Validate() (CustomPreviewGenerator.cs:30) when CustomPreviewGenerationSettings.Width <= 0. Width is the output render resolution: it is propagated into SceneScreenshotterSettings.Width (material/model/prefab screenshots) and TextureTypeGeneratorSettings.MaxWidth. A zero or negative value would produce an invalid RenderTexture. Validate() runs inside Generate() before GenerateImpl() and outside its try/catch, so the ArgumentException propagates uncaught to the caller (typically the Preview Generator window).

Source

Thrown at TestProjects/AssetStoreUploads/Packages/com.unity.asset-store-tools/Editor/Previews/Scripts/Generators/CustomPreviewGenerator.cs:30

{
    internal class CustomPreviewGenerator : PreviewGeneratorBase
    {
        private CustomPreviewGenerationSettings _customSettings;

        public override event Action<float> OnProgressChanged;

        public CustomPreviewGenerator(CustomPreviewGenerationSettings settings)
            : base(settings)
        {
            _customSettings = settings;
        }

        protected override void Validate()
        {
            base.Validate();

            if (_customSettings.Width <= 0)
                throw new ArgumentException("Width should be larger than 0");

            if (_customSettings.Height <= 0)
                throw new ArgumentException("Height should be larger than 0");

            if (_customSettings.Depth <= 0)
                throw new ArgumentException("Depth should be larger than 0");

            if (_customSettings.NativeWidth <= 0)
                throw new ArgumentException("Native width should be larger than 0");

            if (_customSettings.NativeHeight <= 0)
                throw new ArgumentException("Native height should be larger than 0");
        }

        protected override async Task<PreviewGenerationResult> GenerateImpl()
        {
            var result = new PreviewGenerationResult()
            {

View on GitHub (pinned to c21bf496bc)

Solutions

1. Set CustomPreviewGenerationSettings.Width to a positive value (e.g. 128 or 256) before calling Generate().
2. When building settings programmatically, populate all five dimension fields together (Width, Height, Depth, NativeWidth, NativeHeight) right after construction.
3. In the Preview Generator window, confirm the Width field holds a positive number before clicking Generate.

Example fix

// before
var settings = new CustomPreviewGenerationSettings {
    InputPaths = paths, OutputPath = outPath,
    Height = 128, Depth = 100, NativeWidth = 1024, NativeHeight = 1024
};
await new CustomPreviewGenerator(settings).Generate(); // throws

// after
var settings = new CustomPreviewGenerationSettings {
    InputPaths = paths, OutputPath = outPath,
    Width = 256, Height = 128, Depth = 100, NativeWidth = 1024, NativeHeight = 1024
};
await new CustomPreviewGenerator(settings).Generate();

// C# - check before Generate()
var s = settings as CustomPreviewGenerationSettings;
if (s != null && s.Width <= 0)
    throw new InvalidOperationException("CustomPreviewGenerationSettings.Width must be > 0 before generating previews.");

static bool HasValidWidth(CustomPreviewGenerationSettings s) => s != null && s.Width > 0;

try { await generator.Generate(); }
catch (ArgumentException ex) when (ex.Message.Contains("Width")) { /* report invalid width, fix settings */ }

When it happens

Trigger: Calling generator.Generate() on a CustomPreviewGenerator built from a CustomPreviewGenerationSettings whose Width field was never assigned (default int = 0), or was explicitly set to 0 or a negative number. Occurs when settings are constructed programmatically without setting Width, or when the Preview Generator window submits while the width field is empty.

Common situations: Default-initializing a settings object with `new CustomPreviewGenerationSettings()` and forgetting Width (all int fields default to 0); a UI/code path that clears dimensions before validation; migration from an older settings shape that lacked Width.

Related errors

• Height should be larger than 0
• Depth should be larger than 0
• Native width should be larger than 0
• Native height should be larger than 0
• Chunk size must be larger than 0

AI-assisted analysis of CoplayDev/unity-mcp@c21bf496bc (2026-08-13). Data as JSON: /api/errors/46a09ab87473e7cb. Report an issue: GitHub.