Nano Banana 2 Tutorial: Generating Soft Contact Shadows for Floating Product Renders

Understanding Soft Contact Shadows in AI Generation

Creating a realistic product render often hinges on the relationship between the object and the surface it occupies. When a product appears to float, the shadow is the primary visual cue that grounds it in space. Without a shadow, an object looks detached; with a harsh, black shadow, it looks like a sticker pasted onto a background. The goal of this tutorial is to generate soft contact shadows that mimic natural light diffusion.

In the context of Nano Banana 2, which refers to the AI image generation tool and not a physical cosmetic brand, achieving this effect requires precise prompt engineering. The model needs clear instructions regarding the lighting environment and the specific nature of the shadow. A soft contact shadow is distinct from a long cast shadow. It sits directly beneath the object where the gap between the product and the floor is smallest, fading out quickly as distance increases. This technique ensures the shadow intensity matches the object's perceived elevation, making the floating effect look intentional and physically plausible rather than accidental.

It is important to note that prompt instructions describe desired outcomes but do not guarantee identity, label, object, or typography preservation. Users should treat example prompts as starting points to be refined based on their specific product images.

Prerequisites and Model Selection

Before attempting to generate these renders, ensure you are using the correct version of the tool. Google documents Nano Banana 2 as Gemini 3.1 Flash Image (gemini-3.1-flash-image). This model is suitable for general text-to-image and image-to-image workflows. For users considering other versions, Google describes Nano Banana 2 Lite as focused on speed and cost. However, it is not optimized for multiple reference inputs or multi-turn sequential editing. Therefore, if your workflow involves refining a shadow over several steps or using complex reference images, Nano Banana 2 Lite may yield inconsistent results without explaining this limitation.

You will need a base image of your product. This can be generated via text-to-image or uploaded via image-to-image. Ensure the product is isolated or clearly defined against a neutral background to give the AI the best chance of calculating the shadow geometry correctly. If you are working with a complex scene, remember that the tool does not support guaranteed outcomes, and results may vary based on the complexity of the input.

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Step-by-Step Workflow for Shadow Generation

Follow these numbered steps to create a floating product render with soft contact shadows using Nano Banana 2.

1. Prepare Your Input: Upload your product image or generate a clean base image of the product. Ensure the lighting direction is consistent with where you want the shadow to fall. If the product is already rendered, you may need to mask out existing shadows before re-generating them for better control.
2. Construct the Prompt: Write a detailed prompt that explicitly requests a soft contact shadow. Avoid generic terms like "shadow" alone. Instead, specify the quality of the shadow. Use phrases such as "subtle ground-contact shadow," "soft diffuse shadow underneath," or "natural ambient occlusion." Mention the elevation level, for example, "product floating slightly above a white surface with a soft shadow directly beneath."
3. Set Parameters: In the Nano Banana 2 interface, select the appropriate model settings. Since you are focusing on detail and realism, avoid the Lite version if you require high fidelity in shadow texture. Adjust the guidance scale if available to balance adherence to your prompt with creative freedom.
4. Generate and Review: Run the generation. Observe the result closely. Does the shadow fade naturally? Is it too dark or too faint? The shadow should be darkest right under the object and soften rapidly as it moves outward.
5. Iterate: If the shadow is too hard, add keywords like "blurred edge" or "volumetric softness." If it is missing entirely, reinforce the instruction about the "ground plane" or "surface contact."

Evaluating Results and Troubleshooting Common Issues

Judging the success of your generation relies on visual inspection of the shadow's gradient. A successful soft contact shadow will have no sharp edges. It should look like light is being blocked by the object but diffusing through the air immediately below it. If the shadow appears as a solid black shape with a crisp outline, the prompt likely lacked descriptors for softness or diffusion.

Common issues include the shadow appearing disconnected from the object or the product looking like it is sinking into the floor. To fix a disconnected shadow, ensure your prompt explicitly links the shadow to the "bottom of the object." If the product sinks, increase the mention of "floating" or "elevated" in your prompt to create more negative space between the object and the shadow source.

Remember that untested prompt examples provided here are just examples. They serve as a template for your own experimentation. Do not assume that every prompt will work identically across different product types. Always test with your specific imagery to refine the parameters. By following these guidelines, you can consistently produce professional-grade renders that utilize soft contact shadows to enhance the perception of depth and realism.

For more information on the underlying technology, refer to the official documentation at https://ai.google.dev/gemini-api/docs/image-generation.