LykosAI/StabilityMatrix · error · ValidationException

BaseClipVision not set

Error message

BaseClipVision not set

What it means

When image-to-video mode is active (IsDenoiseStrengthEnabled), WanSamplerCardViewModel.ApplyStep() builds a CLIPVisionEncode node that requires a CLIP Vision model. It reads e.Builder.Connections.BaseClipVision and throws ValidationException("BaseClipVision not set") when the upstream connection was never populated, because a CLIPVisionEncode node cannot be emitted without a ClipVision model input.

Solutions

1. Install the required CLIP Vision model for Wan (e.g. clip_vision_h) via the Model Browser into the clip_vision models folder, then select it so BaseClipVision gets populated.
2. Verify Settings -> ComfyUI points at the correct models directory (or shared ComfyUI folder) so installed clip_vision models are discovered; restart the app after installing.
3. Disable the image-to-video / denoise-strength mode on the Wan sampler card if you don't intend img2vid generation.
4. If driving the builder in code, set e.Builder.Connections.BaseClipVision to the CLIP Vision model before ApplyStep.

Example fix

// before
ClipVision = e.Builder.Connections.BaseClipVision
    ?? throw new ValidationException("BaseClipVision not set"),
// after (caller-side guard)
if (e.Builder.Connections.BaseClipVision is null)
    throw new ValidationException("Select a CLIP Vision model for image-to-video generation (Settings -> install clip_vision model).");

if (card.IsDenoiseStrengthEnabled && e.Builder.Connections.BaseClipVision is null)
    throw new ValidationException("Image-to-video requires a CLIP Vision model; install/select one first.");

bool CanRunImgToVid(WanSamplerCardViewModel c, Connections conn) =>
    !c.IsDenoiseStrengthEnabled || conn.BaseClipVision is not null;

try { card.ApplyStep(e); }
catch (ValidationException ex) when (ex.Message == "BaseClipVision not set")
{ PromptInstallClipVisionModel(); }

When it happens

Trigger: Running a Wan image-to-video generation where the BaseClipVision connection is null — the CLIP Vision model was not selected/chosen in the UI, the required CLIP-Vision checkpoint (e.g. clip_vision_h for Wan) is not installed or not loaded into Connections, or an upstream module that normally sets BaseClipVision did not run.

Common situations: User enables img2vid/denoise-strength mode on the Wan card without a CLIP Vision model downloaded; shared ComfyUI models folder not configured so the clip_vision model isn't discovered; workflow restored from a saved prompt where the CLIP Vision selection was lost; calling ApplyStep programmatically on a bare builder without setting Connections.BaseClipVision.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• Sampler not selected
• : Model not selected
• Scheduler not selected
• Client is not connected
• Prompt extensions not installed

AI-assisted analysis of LykosAI/StabilityMatrix@af93d6ef57 (2026-09-12). Data as JSON: /api/errors/afa42c0ca7c5cbaf. Report an issue: GitHub.

Appendix: source

Thrown at StabilityMatrix.Avalonia/ViewModels/Inference/WanSamplerCardViewModel.cs:73

        e.Builder.Connections.PrimaryCfg = CfgScale;
        e.Builder.Connections.PrimarySteps = Steps;
        e.Builder.Connections.PrimaryModelType = SelectedModelType;

        e.Temp = e.CreateTempFromBuilder();

        var conditioning = e.Temp.Base.Conditioning.Unwrap();

        var isImgToVid = IsDenoiseStrengthEnabled;

        if (isImgToVid)
        {
            var clipVisionEncode = e.Nodes.AddTypedNode(
                new ComfyNodeBuilder.CLIPVisionEncode
                {
                    Name = e.Nodes.GetUniqueName(nameof(ComfyNodeBuilder.CLIPVisionEncode)),
                    ClipVision =
                        e.Builder.Connections.BaseClipVision
                        ?? throw new ValidationException("BaseClipVision not set"),
                    Image = e.Builder.GetPrimaryAsImage(),
                    Crop = "none",
                }
            );

            var wanImageToVideo = e.Nodes.AddTypedNode(
                new ComfyNodeBuilder.WanImageToVideo
                {
                    Name = e.Nodes.GetUniqueName(nameof(ComfyNodeBuilder.WanImageToVideo)),
                    Positive = conditioning.Positive,
                    Negative = conditioning.Negative,
                    Vae = e.Builder.Connections.GetDefaultVAE(),
                    ClipVisionOutput = clipVisionEncode.Output,
                    StartImage = e.Builder.GetPrimaryAsImage(),
                    Width = Width,
                    Height = Height,
                    Length = Length,
                    BatchSize = e.Builder.Connections.BatchSize,

View on GitHub (pinned to af93d6ef57)