Lumion's AI PBR Material Generator includes stone as one of its built-in material type presets. Like the wood and concrete presets, it extracts PBR maps from a reference photograph of a stone surface — practical for architects matching a specific material from a building or sample board. Outside the Lumion ecosystem, or when the target stone material doesn't exist as a physical sample, a different approach is needed.

This guide covers how to generate stone and masonry PBR textures from text descriptions using Grix, with output that imports directly into Blender, Unreal Engine, Unity, and Godot. No Lumion subscription required. No reference photo required.

What Lumion's Stone Preset Covers

Lumion Cloud's AI Material Generator handles stone as a photo-to-PBR extraction: you upload a photograph of the stone surface and receive basecolor, normal, roughness, metalness, and height maps calibrated for Lumion's renderer. For architects documenting existing stone — a cladding system from a facade sample, a granite countertop from a material library, or a site-specific masonry type — this is a legitimate workflow when the physical material is accessible and photographable.

Four constraints limit Lumion's stone preset for broader use:

Photo requirement. Stone materials that exist only as description — a fantasy slate in a game environment, a stylized basalt for a sci-fi corridor, aged ashlar from a historical reference — have no photographable source. Lumion's tool requires an actual photograph to function.

Renderer lock-in. Output is calibrated for Lumion's rendering engine. The PBR maps don't export as portable PNG sets for use in Blender, Unreal Engine 5, Unity, or Godot. Teams working in any engine other than Lumion cannot use the output.

Subscription cost. Lumion Pro subscriptions start at approximately $60-75/month. For teams whose primary need is stone material generation for game development or cross-platform visualization, this is a high cost for a single-engine workflow.

Variation limits. Photo-to-PBR extraction is constrained by the source photograph. Generating 20 variations of aged limestone — different weathering stages, different surface deposits, different degrees of pitting — requires 20 distinct photographs of distinct physical samples.

Text-to-PBR Stone Generation with Grix

Grix generates stone PBR textures from text descriptions with no photo input and no renderer lock-in. Enter a stone description at grixai.com/try — free trial, no login required — and receive a ZIP containing five calibrated PBR maps: basecolor, normal, roughness, metalness, and height. Generation takes approximately 25 seconds. Maps tile seamlessly and import into any renderer that accepts standard PBR inputs.

Pricing starts at $8/month for the Light plan. See grixai.com/pricing for full plan details. The free trial provides full-resolution output with no account creation required.

Stone Type Vocabulary for Prompt Precision

Stone texture quality depends heavily on geological specificity. The following elements have the most impact on output:

Rock type and formation. "Granite" produces a coarse-grained igneous texture with interlocking crystal structure, salt-and-pepper basecolor, and high frequency surface normal detail. "Basalt" produces a fine-grained volcanic texture with dark grey-black coloration and columnar joint lines when described as "basalt columns." "Limestone" produces a sedimentary texture with horizontal bedding lines, fossil inclusions when specified, and medium-fine grain. "Slate" produces thin parallel cleavage planes, dark grey with slight blue or green cast depending on mineral content. "Marble" produces crystalline calcite texture with distinctive vein patterns. "Sandstone" produces a warm ochre or red-brown surface with visible sediment grain and sandy texture in the normal map.

Surface finish. "Polished" reduces roughness to approximately 0.2-0.35 and produces strong specular reflection. "Honed" gives a matte surface with roughness around 0.55-0.7 — smooth but not reflective. "Flamed" (thermally treated) opens the crystal structure and produces high roughness (0.85+) with a frosty, matte surface. "Bush-hammered" creates a deeply textured mechanical finish with regular stipple marks in the normal map. "Split-face" produces an irregular fracture surface with high relief in the height map. "Sandblasted" creates a uniform fine-grain texture across the surface.

Weathering and age. "Fresh quarried" produces sharp crystal edges and clean mineral coloration. "Weathered" adds surface erosion, rounding of edges, and biological staining. "Lichen-covered" adds green-grey biological growth patches. "Water-stained, rust bleeding from iron inclusions" adds reddish-brown streaks running vertically in the basecolor. "Salt-weathered coastal stone" adds white efflorescence deposits and surface pitting.

Scale and tile context. Specifying "ashlar masonry" produces regular rectangular cut blocks with visible joint lines in the normal map. "Random rubble" produces irregular uncut stone. "Coursed rubble" produces horizontal courses of irregular stone. "Flagstone paving" produces flat slabs with irregular perimeter joints.

Stone Prompt Examples for Common Material Needs

Polished black granite: "Absolute Black granite, polished mirror finish, tight crystalline grain, faint grey fleck pattern, 0.2 roughness" — countertop, flooring, and monumental facade material.

Architectural limestone cladding: "French limestone, honed finish, warm cream-grey, fine even grain, faint horizontal bedding, 0.65 roughness" — contemporary commercial facade material.

Grey slate flooring: "Welsh grey slate, riven surface, slight blue-grey cast, parallel cleavage planes, 0.75 roughness" — interior and exterior flooring for residential and commercial projects.

Aged sandstone masonry: "Red sandstone ashlar, weathered, biological staining, surface erosion at edges, warm terracotta-red, 0.82 roughness" — historical building material for visualization or game environments.

Fantasy dark basalt: "Dark volcanic basalt, rough fracture surface, black with subtle blue-grey mineral, irregular surface detail, 0.88 roughness" — game environment, sci-fi, or fantasy material with no real-world photographic equivalent.

White Carrara marble: "Carrara marble, high polish, white ground with thin grey veins, crystalline surface, 0.15 roughness" — luxury interior material for architectural visualization and product renders.

Blender Stone Material Workflow

In Blender, connect all five maps from the Grix ZIP to a Principled BSDF shader. Stone materials benefit significantly from height map displacement — stone surface relief at close camera distances reads clearly when displacement is active.

Enable Cycles render engine. In Material Properties, set Displacement to "Displacement and Bump." Connect the height map through a Displacement node to the Material Output Displacement input. Appropriate displacement scale values vary by stone type: polished granite warrants 0.001-0.003m (very fine), split-face slate warrants 0.008-0.015m (significant relief), rough quarry stone warrants 0.01-0.025m.

Grix outputs OpenGL-convention normal maps. Blender expects OpenGL convention natively — no channel flip required on import. Set the normal map Image Texture node to Non-Color data and connect through a Normal Map node set to Tangent Space before the Principled BSDF Normal input.

Stone materials are non-metallic: the metalness map will return near-zero values for all standard stone types. Exception: metallic ore inclusions like pyrite in slate can produce faint metallic response — Grix handles this correctly when specified in the prompt.

Unreal Engine 5 Stone Material Workflow

UE5 uses DirectX normal map convention. Enable "Flip Green Channel" in the Texture Editor or at import for the normal map only. All other maps import without modification. Set the normal map Texture Compression to "Normalmap (DXT5, BC5 on DX11)."

For stone facades and exterior surfaces: enable Virtual Textures for large surfaces to maintain texture resolution at varying camera distances. For interior stone flooring: standard texture streaming handles most cases adequately.

Nanite displacement workflow: connect Height to World Displacement through a multiply node. Stone displacement scales vary considerably — polished marble warrants 0.002-0.005 multiply scale; rough quarry stone warrants 0.05-0.15. Enable Tessellation at a level appropriate for the camera distance. For hero material shots, 64-128 tessellation provides good resolution for displacement detail from Grix height maps.

For Lumen global illumination: stone materials with roughness above 0.6 are primarily diffuse reflectors and read correctly in Lumen without special material setup. Polished stone (roughness below 0.35) benefits from enabling Screen Space Reflections or Ray Traced Reflections to capture the specular response correctly.

Unity Stone Material Workflow

Import all five maps from the Grix ZIP into your Unity project. In Universal Render Pipeline (URP), create a Lit material and assign: Basecolor to Base Map, Normal map (with green channel flip enabled in import settings for DirectX convention) to Normal Map, Roughness to the Smoothness channel (inverted — Unity uses Smoothness, not Roughness: either invert in an external tool or use a custom shader), Metallic to Metallic Map, Height for parallax occlusion mapping.

In HDRP: use the Mask Map channel-packing workflow if needed (Metallic R, AO G, Detail B, Smoothness A). The five individual Grix maps function directly with standard HDRP Lit shaders without channel packing when used as separate inputs.

When Lumion's Stone Preset Makes Sense

Lumion's stone preset is the appropriate tool when you need to exactly match a specific real-world stone from a supplier's sample — a particular granite specification from a facade supplier, a limestone type used in an existing building being extended, or a stone veneer product from a manufacturer's catalog. When physical sample fidelity matters more than portability or cost, photo-to-PBR extraction from the actual material is the correct approach.

For all other stone material needs — custom geological descriptions, imagined stone for game or film environments, volume production across many stone variations, or multi-engine project support — text-to-PBR generation at grixai.com/try is faster and significantly cheaper. See the related guides for concrete, wood, and brick material types in this series.

Frequently Asked Questions

Does Grix support both igneous and sedimentary rock types?

Yes. Text-to-PBR generation handles any geological description: igneous types (granite, basalt, obsidian, pumice), sedimentary types (limestone, sandstone, shale, chalk), and metamorphic types (marble, slate, quartzite, schist). Prompt specificity determines output quality — include rock type, grain size, color description, and surface finish for best results.

Can I generate stone with visible joint patterns for masonry walls?

Yes. Describe the masonry pattern in the prompt: "ashlar limestone with regular rectangular joints," "random rubble granite wall," or "coursed sandstone with horizontal bedding joints." The normal map and basecolor will include joint geometry and shadow appropriate to the masonry type described.

How does Grix output compare to photogrammetry for stone materials?

For game environments and architectural visualization at typical rendering distances, Grix text-to-PBR produces equivalent visual results. Photogrammetry captures specific real-world surface geometry and is superior when exact physical fidelity to a particular stone sample is required — client-specified heritage materials, structural elements requiring exact spec matching. For volume production, stylized materials, and materials without a specific real-world counterpart, text generation is faster and more flexible.

Do I need a Lumion subscription to use Grix for stone textures?

No. Grix is a standalone tool at grixai.com/try — no renderer subscription required. The free trial provides full-resolution output without account creation. Paid plans start at $8/month for the Light plan.

Are Grix stone textures compatible with Lumion if I have a subscription?

Yes. Grix outputs standard PBR map sets as portable PNGs. These import into Lumion as custom materials through Lumion's standard material import workflow, giving you text-to-PBR generation with Lumion rendering if that combination is useful for your workflow.