ComfyUI-RUM-Anima-XPred

ComfyUI RUM Anima XPred

Custom nodes for sampling RUM Anima x-pred checkpoints in ComfyUI.

Why This Node Exists

Anima x-pred checkpoints do not output the original Flow Matching velocity directly. They output clean latent x, and the sampler must read out the Euler update direction as:

v = (z - x_pred) / sigma

Regular Anima/FM ComfyUI samplers expect a velocity-prediction checkpoint, so wiring an x-pred checkpoint into those nodes uses the wrong model semantics. These nodes keep sampling in x-pred mode and use the velocity readout only inside the Euler update.

Install

Clone or copy this repository into ComfyUI/custom_nodes/:

cd ComfyUI/custom_nodes
# place the ComfyUI-RUM-Anima-XPred folder here

Put model files under ComfyUI's normal models/ folders:

ComfyUI/models/diffusion_models/  xpred-adapter-checkpoint.safetensors
ComfyUI/models/text_encoders/     qwen_3_06b_base.safetensors
ComfyUI/models/vae/               qwen_image_vae.safetensors
ComfyUI/models/loras/             anima-lora.safetensors

The loader uses ComfyUI dropdowns for these files instead of absolute path text boxes. The x-pred checkpoint is an Anima DiT checkpoint and is loaded directly through the normal Anima DiT loader, so it belongs in the same diffusion_models folder as ordinary Anima DiT files. A separate base DiT file is not required.

Nodes

• Load Anima XPred Model

  • Loads the Anima DiT x-pred checkpoint, text encoder, and VAE.
  • Use xpred-adapter-checkpoint.safetensors, not xpred-train-state.pt.

• Load Anima XPred LoRA

  • Loads an Anima DiT LoRA from ComfyUI's models/loras folder.
  • Takes and returns RUM_ANIMA_XPRED, so it belongs between the model loader and sampler.

• Sample Anima XPred

  • Runs the dedicated x-pred sampler with heun or euler: v = (z - x_pred) / sigma
  • The Heun mode follows JLT's predictor-corrector structure and uses Euler for the final step into sigma=0.
  • Decodes the final latent with the Anima/Qwen VAE.
  • Outputs a ComfyUI IMAGE plus the raw latent dictionary.

Minimal Workflow

Connect:

Load Anima XPred Model -> Sample Anima XPred -> Preview Image / Save Image

With a LoRA:

Load Anima XPred Model -> Load Anima XPred LoRA -> Sample Anima XPred -> Preview Image / Save Image

Do not connect an x-pred checkpoint to a regular Anima/FM velocity sampler. The checkpoint predicts clean latent x, not velocity.