How to structure prompts for AI Visualizer in Archicad 30

[Mohamed Raslan]

Yesterday Archicad 30 was released and with it the latest AI visualizer.

One of the expected use cases is to use your 3D model in Archicad to create a realistic rendering to present internally or to your clients.

The best results come from a simple three-part structure. The AI should restyle your model, not redesign it.

1. Lock the base image
Start by telling the AI to treat your 3D view as the exact reference:

"Use the provided 3D model image as the exact base."

2. List what must NOT change
Be specific. Name the elements that matter in your project, then add a catch-all rule:

"Keep the building geometry, massing, roof lines, window and door positions and sizes, timber slat shutters and balcony, terrain shape, camera angle and framing completely unchanged. Do not add, remove or move any architectural elements."

3. Describe the photograph, not the building
Now define the look using photography language: weather, season, time of day, camera and lens, viewpoint:

"Create a photorealistic architectural photograph taken on an overcast autumn afternoon with a full-frame camera and a 24mm tilt-shift lens, eye-level view, natural perspective with vertical lines kept straight."

Why it works

• Order matters in instruction based models like Nano Banana 2. Constraints first, atmosphere second. The AI treats the model as fixed and only "photographs" it.
• Naming elements (shutters, balcony, roof lines) works better than a generic "keep everything the same."
• Tilt-shift + "vertical lines kept straight" avoids the converging verticals common in AI renders.
• Overcast light is forgiving: soft shadows, no harsh artifacts, and materials read well.

Quick template

Use the provided 3D model image as the exact base. Keep [list your key elements] completely unchanged. Do not add, remove or move any architectural elements. Create a photorealistic architectural photograph taken [weather/season/time of day] with [camera + lens], [viewpoint], [perspective notes].

Tips

• Swap only the last sentence to explore moods (golden hour, snowy winter, blue hour) while the geometry stays locked.
• Avoid vague style words like "beautiful" or "stunning." Concrete photographic details do the work.
• Start from a clean model view: clear camera angle, simple sky, no section lines or overlays.

Here is a step by step instructions on how to do that:

1. Capture the 3D model from your active 3D view

2.Then paste your prompt, in this example the prompt used was: 

Use the provided 3D model image as the exact base. Keep the building geometry, massing, roof lines, window and door positions and sizes, timber slat shutters and balcony, terrain shape, camera angle and framing completely unchanged. Do not add, remove or move any architectural elements.
Create a photorealistic architectural photograph taken on an overcast autumn afternoon with a full-frame camera and a 24mm tilt-shift lens, eye-level view, natural perspective with vertical lines kept straight.

Result using the basic model from AI model selector:

Result using Nano Banana 2 from AI model selector:

Happy to hear what variations others are using!

[CosminF]

Some more takeaways based on my experience with AI renderers, not only the one within AC. 
These tips yielded some good results (to my eyes at least)

Textures
- be precise in what you want. Don't say wood, say light oak, mahogany etc. Be specific with what texture you aim for. Especially if the 3D screenshot isn't very detailed. Also, as Mohamed said - think of scenes. If it just rained, the materials might look different. If it is raining, people are hurrying indoors, trees might be (slightly) blown by the wind etc. Tell the story. 
- be precise in environment also. Say how you want the grass to look, where the snow is piled up, what type of forest is nearby, how tall is it, how light falls through it and casts a shade on the ground, if the dirt road is slightly damp, with puddles or not etc.

Entourage:
- ask for people - they can be sitting, reading, walking, blurry silhouettes, dark blurry silhouettes, dressed sharply, dressed casually, etc.  Also, if you have a bunch of people in a room, make sure to indicate randomness: if a room of people are all looking at a presentation, ask for some variation (some might take notes, other look out the window, etc). Be sure to double check the proportions. Sometimes people are out of scale.

- pets and decor - again, specificity. Blurry silhouettes of birds flying in the top right corner of the image

Artificial lights:
-You can indicate position in the model with bright textures and say something like: all magenta circles are actually spot lights, 4500k in color, casting a very faint shadow. Make sure to indicate light type, intensity, ambiance, hue.

Natural lights:

- try to have the sun position correct in the 3D window in Archicad. It leads to less hallucinations (it won't interpret shadows as something else as much).

Color grading, contrast, etc
- this may be more for post-processing which is needed usually but ask for the correct color grading of the ambiance you are going for. Again, storytelling.

References
- search images that have the general ambiance you're aiming for. You can either try to describe them yourself or ask an AI to describe it as a prompt. (turn the image to text) and then "borrow" descriptors from there.