Guide · · 7 min read
Materials that read as real: wood, stone and glass
The tell of a generated image is almost never the geometry. It is a surface with no scale, no wear and one uniform sheen. Here is how to avoid all three.
Ask an architect what gives a generated image away and they will not say the proportions. They will say it looks like a toy. That impression comes from surfaces, and almost always from the same three faults: the material has no scale, it has no history, and everything in the frame is shiny in exactly the same way.
The three faults, and what causes them
- No scale. A brick that is not the size of a brick turns a building into a model of itself. Scale is read from repetition — coursing, board widths, panel joints — so a surface with no repeat in it has nothing to be read against.
- No history. Real materials have been rained on. Stone streaks below a sill, timber greys where the sun hits it, concrete darkens at the base of a wall. An image with no wear anywhere reads as a catalogue photograph of a sample, not as a building on a street.
- One sheen for everything. If the render gives the same specular response to plaster, wood and glass, your eye reads the whole frame as one plastic material with different colours painted on it. This is the single strongest tell, and it is also the easiest to fix.
Materials are swatches, not adjectives
In a prompt-based tool a material is a word, and a word is a negotiation: “warm oak” arrives as whatever the model believes warm oak means today, and it means something different in the next generation. Here a material is a swatch you assign to a surface, and the surface is one you picked in the model. That is the difference between describing an intention and specifying a facade — and it is why the same project comes back consistent across a set of twenty directions.
Two habits follow from that, and they are the whole article in miniature: assign the important surfaces explicitly rather than letting the run choose, and give the run a reference image whenever the material is specific rather than generic.
Wood
Timber is the most forgiving material to get roughly right and the least forgiving to get exactly right, because everyone has touched it. Three things to check before you accept a frame:
- Grain direction follows the member. Vertical on a post, along the run on a slat, across the width on a floorboard. A facade where the grain runs the same way on every piece is a facade wrapped in wallpaper.
- The repeat is the width of a real board. Slatted screens are the common failure — the rhythm looks right in the thumbnail and reads as corduroy at 4K.
- Tone is decided by the light, not by the swatch. The same oak is honey at golden hour and grey-brown at noon. If the timber is wrong, change the hour before you change the material.
Stone and concrete
Masonry lives or dies on the joint. A stone wall is a pattern of units and mortar, and the pattern carries the scale of the whole building — get the coursing right and a client can measure the storey height with their eye. Board-marked concrete is the same argument with different units: the boards are the scale.
- Decide the unit before the colour. Ashlar, coursed rubble, brick stretcher bond and precast panels are four different buildings, and they read differently at 50 metres.
- Let the base of the wall be dirtier than the top. It is one of the cheapest cues there is, and its absence is why clean renders feel like renders.
- Concrete is not grey. It is the colour of the sky it is standing under, which is why the same facade in the environment tool can change material temperature without you touching the material.
Glass
Glass is the only material in the frame doing two jobs at once: reflecting what is in front of it and transmitting what is behind it. Which job dominates is decided by the light, not by the glass — a curtain wall at midday is a mirror of the sky, and the same wall at dusk is a lit room with a faint street on top of it.
- Decide first whether this frame is a mirror shot or a lit-interior shot. Both are correct; a frame that is trying to be both reads as fog.
- Whatever is reflected has to exist. A reflection of a building that is not in the scene is the fastest way to lose a client’s trust in an image.
- Interiors need something behind the glass. A blank white void behind a window is the most common interior render failure, and it is exactly what the view outside tool exists for — there is a short lesson on it on the tutorials page.
When to reach for a reference image
Presets cover material families. References pin a specific one. If the client has chosen a particular travertine, or the practice has a house palette, drop a JPG or PNG in with the model — it costs nothing, it survives the whole set, and it removes the single most tedious conversation in concept work, which is the one where everyone agrees the material is “nearly right”.
References are also the honest way to handle a material that has to match something already built: photograph the built thing, put the photograph in, and let the render argue with the photograph rather than with a memory.
Check the surfaces at full size
Materials that look convincing at 1080p can dissolve when they are enlarged, and the three that dissolve first are exactly the three above. Before a frame goes to print, look at it at the size it will be printed — we went through what changes at 4K and 8K in detail, and the short version is that edges and repeats are where the money is.
“An app built by Archviz specialists, for Archviz specialists. A very well-designed set of tools focused on optimizing the workflow of any project — well structured, intuitive, and capable of delivering excellent results.”
Rui Estrelado, 3D Team Manager, airosoandsimetrico.com
Questions we get
- Why do materials look plastic in AI renders?
- Usually because every surface in the frame shares one specular response and none of them carry wear or a scale-giving repeat. Assigning materials explicitly and varying sheen between them fixes most of it.
- Can I match a specific material a client has chosen?
- Yes — add a JPG or PNG of it as a reference alongside the model. The reference pins the palette and finish across the whole set of directions, which a written description cannot do.
- Do materials survive an 8K upscale?
- The upscale resolves detail that was implied at 1080p; it does not invent a repeat that was never there. Materials with a correct unit size and joint pattern hold up; ones that were vague get larger and vaguer.
- Should I fix a material by changing the material or the light?
- Try the light first. Tone, sheen and contrast in a surface are mostly a lighting result, and relighting a finished image is faster and more predictable than swapping the swatch.
