AI Design Face-Off: An Interior Designer's Test of Google's Gemini vs. OpenAI

Written by: Emma Cyrus, Senior Copy, Content & Editorial Writer
Reviewed by: Monika Popescu, Senior Interior Designer at FCI London
Edited by: Zoona Sikander, Head of Content

Estimated Reading Time: 7 minutes 

TLDR: When Google's mysterious Nano Banana image generator appeared on LMArena, the design community wondered whether it truly represented the future of interior visualisation. We put it head-to-head with ChatGPT and Sora using genuine luxury furniture pieces and detailed design briefs, discovering that whilst each tool has its strengths, realistic spatial understanding remains the decisive factor separating useful visualisation tools from those that simply arrange attractive elements without grasping how sophisticated spaces actually function.

Table of Contents

• Enter the Nano Banana Phenomenon
• The Design Challenge: Putting Theory to Practice
• Test One: The Living Room Challenge
• Test Two: The Dining Room Refinement
• The Professional Verdict
• The Broader Implications
• Key Takeaways
• Frequently Asked Questions
• Visit Our Showroom

If you're an interior designer in London or the Home Counties seeking reliable AI visualisation tools for client presentations, this comparative analysis is for you. Design professionals working with luxury furniture brands will also find these practical insights invaluable. We've tested three leading image generators known for their advanced capabilities against genuine luxury furniture pieces. When only the best will do, understanding which tools deliver the sophisticated realism your projects truly deserve makes all the difference.

As an interior designer who's spent the better part of two decades perfecting the art of spatial composition, I find myself constantly evaluating new tools that promise to revolutionise our workflow. The latest buzz in the design community has been around Google's mysteriously named "Nano Banana" - officially known as Gemini 2.5 Flash Image - and whether it lives up to the considerable excitement.

Enter the Nano Banana Phenomenon

Google's Nano Banana first surfaced anonymously on LMArena, where it started "blowing every other image generator out of the water" without any official announcement. The model has since been officially revealed as Google's "state-of-the-art image generation and editing model", claiming to offer "multi-image fusion, character consistency, and text-based editing" capabilities that could genuinely transform how we approach design visualisation.

The claims are certainly ambitious. But as any seasoned designer knows, there's often a considerable gap between marketing promises and real-world performance.

The Design Challenge: Putting Theory to Practice

Naturally, I couldn't resist putting these tools through their paces with a proper design test. I gathered seven luxury furniture pieces - a sofa, coffee table, armchair, sideboard, side tables, floor lamp, and chandelier - and challenged three AI generators to create sophisticated interior compositions.

The competitors? Google's much-lauded Nano Banana, ChatGPT's image generation, and Sora from OpenAI. Each received identical prompts and product images to level the playing field.

Test One: The Living Room Challenge

For the first test, I provided this detailed brief:

"Create a sophisticated modern living room interior. Use the provided product images exactly as they are: a sofa, coffee table, armchair, sideboard, side tables, a floor lamp, and a chandelier. Arrange them naturally as in a real living room: place the sofa as the central seating, with the coffee table in front and the armchair nearby for balance. Position the sideboard against the back wall, styled minimally. Place the side tables beside the sofa and armchair, and the floor lamp in a corner for warmth. Hang the chandelier overhead as the main light source. Ensure realistic proportions, soft natural daylight, and a cohesive high-end look, styled like a luxury interior magazine photo."

The results were rather telling. Sora delivered the most sophisticated composition - realistic proportions, proper spatial relationships, and that ineffable quality we call "magazine-worthy styling." The lighting felt natural, the furniture placement made practical sense, and the overall aesthetic had the polish one expects from high-end interiors.

ChatGPT's effort was adequate but uninspiring - decent composition but lacking the refinement and realistic quality that separates amateur arrangements from professional design. The proportions felt slightly off, and the overall result lacked the sophisticated edge required for luxury interiors.

Nano Banana, despite its stellar reputation, took considerable liberties with my brief. Rather than respecting the specific products provided, it seemed to interpret them as mere suggestions, fundamentally altering most pieces. For a tool marketed on its precision, this felt like a significant misstep.

We decided to give Nano Banana another chance - perhaps the prompt got too long/complicated for it. So we tried again with this simple prompt 'Compile all products in the attached image to create a modern living room. Very high end interior design." Below is the result we got - once again, not too impressive. Another limitation of the tool is that so far there is no option to control the aspect ratio, unlike other tools like MidJourney or Sora.

Test Two: The Dining Room Refinement

Determined to give Nano Banana another opportunity, I presented a second challenge focused on a single statement piece - a dining table - with this prompt:

"Create a 3D-rendered image of a luxurious open-plan dining room. The space should be modern and sophisticated, featuring high-end furniture and decor. Place the provided dining table as the centerpiece of the room, surrounded by elegant chairs. The room should have sleek, clean lines with neutral tones like beige, grey, and gold, accented by statement lighting, plush rugs, and stylish decor. The atmosphere should feel spacious and airy, with large windows allowing soft natural light to flood the room. The overall design should evoke a sense of luxury and refined taste."

Once again, Sora proved superior - delivering a realistic, beautifully proportioned space that genuinely captured the essence of luxury open-plan living. The lighting was exquisite, the materials felt authentic, and the overall composition had that coveted "designed rather than arranged" quality.

ChatGPT struggled with dimensional accuracy - chairs that looked more like design sketches than finished furniture, and proportions that would make any self-respecting space planner wince. The quality simply wasn't there for professional use.

Nano Banana managed a decent attempt but missed crucial brief requirements - the "open-plan" concept seemed lost in translation, resulting in a more enclosed space that fundamentally misunderstood the spatial relationship I'd requested.

The Professional Verdict

From a pure design perspective, Sora emerged as the clear winner.

Its ability to understand spatial relationships, maintain realistic proportions, and deliver that polished, magazine-quality aesthetic made it the obvious choice for serious design work. The tool seems to grasp the nuanced differences between merely arranging furniture and actually designing a cohesive space.

However - and this is rather important - this isn't necessarily the end of the story for Nano Banana.

Google's tool offers character consistency and multi-image fusion capabilities that could prove invaluable for other aspects of design work. While it may stumble on precise furniture placement, its strength in maintaining design elements across multiple iterations could make it excellent for mood boards, style development, and client presentations.

The Broader Implications

What this testing revealed is that we're still in the early days of AI understanding sophisticated design principles. While these tools can certainly create visually appealing images, the nuanced understanding of how spaces actually function - the way light moves, how furniture relates to human movement, the subtle balance between form and function - remains elusive.

For now, Sora appears to be the most reliable choice when you need realistic, professionally-polished interior visualisations. But keep watching Nano Banana - Google's approach to character consistency and iterative design could evolve into something rather special once they sort out their spatial awareness.

The real question isn't whether AI will replace our design intuition - it's whether these tools can learn to enhance our creative process whilst respecting the fundamental principles that separate good design from mere decoration.

What's your experience with AI design tools? Have you found any that truly understand the difference between arranging furniture and creating a sophisticated interior space? Speaking of sophisticated interior spaces - if you're curious to see how the real thing compares to these digital interpretations, we'd love to welcome you to our London showroom. Because whilst AI might be getting rather clever, there's still nothing quite like experiencing exceptional design in person.

Key Takeaways

• Sora delivers superior spatial understanding with realistic proportions, proper furniture relationships, and that magazine-quality finish that separates professional visualisation from mere arrangement.
• Nano Banana excels at character consistency and shows genuine promise for mood boards, though it struggles with precise furniture placement and aspect ratio control.
• ChatGPT remains perfectly serviceable for initial ideation but lacks the dimensional accuracy required for serious client presentations.
• Realistic spatial awareness, understanding how light moves, how furniture relates to human movement, and the balance between form and function, separates genuinely useful tools from those creating merely attractive images.
• AI visualisation enhances rather than replaces design intuition, with the most sophisticated results coming from designers who understand how to brief them properly.

Frequently Asked Questions

Which AI image generator is genuinely best for interior design visualisation?
Based on extensive testing with luxury furniture pieces, Sora currently leads for professional design work. It demonstrates superior understanding of spatial relationships, maintains realistic proportions consistently, and delivers that polished aesthetic essential for client presentations. Whilst Nano Banana shows promise for character consistency and ChatGPT handles basic concepts adequately, only Sora genuinely grasps the nuanced difference between arranging furniture and designing cohesive spaces.

Can AI tools understand complex interior design briefs accurately?
Rather mixed results, honestly. Our testing revealed that detailed briefs sometimes confuse rather than clarify - Nano Banana took considerable liberties with specific product requests, whilst simplified prompts didn't necessarily improve outcomes. Sora proved most reliable at interpreting sophisticated requirements, particularly understanding concepts like "open-plan living" or "magazine-worthy styling." The key appears to be finding the sweet spot between detailed direction and allowing the tool room to interpret design principles naturally.

Should interior designers worry about AI replacing their expertise?
Not particularly. Whilst these tools create visually appealing images, they still lack the nuanced understanding of how spaces actually function - the way light moves through rooms, how furniture relates to human movement patterns, the subtle balance between form and function. What AI offers is enhancement rather than replacement, particularly for client visualisations and concept development. The designers who thrive will be those who master these tools whilst maintaining the fundamental design principles that separate good spaces from mere decoration.

How does Nano Banana compare to other AI tools for furniture visualisation?
Google's Nano Banana demonstrates impressive character consistency and multi-image fusion capabilities, making it potentially excellent for mood boards and style development. However, it struggles with precise furniture placement and spatial relationships compared to Sora. The tool's current limitation in aspect ratio control also proves frustrating. Whilst it may not excel at realistic room layouts presently, its iterative design capabilities suggest considerable potential once Google refines its spatial awareness.

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