Each component provides a visual preview of how it transforms its input, which can be seen once its input socket has been set up. When you modify the input component, or a connected component earlier in the model's graph, each affected component will update its preview. PerceptiLabs provides this visualization by running the model using the first sample of data from your model's input component(s). This allows you to see how your model is transforming data as you edit it, and effectively separates modelling from training, since you don't need to run the whole model just to see if its' working correctly.