Photo-sourced and scanned materials

A photo-sourced material starts from photographs of a real surface rather than from painting or nodes. The range runs from a single phone photo turned into physically based rendering maps in seconds, to hundreds of carefully lit photos reconstructed into a measured surface with photogrammetry. More photos and more control give more accurate height and colour, at the cost of time and equipment.

Photo-sourced materials end up used like any other: as tileables, decals, trims or unique textures. See ways to texture an environment.

#Three levels of capture

#1. Single photo to material

Software estimates height, normal and roughness from one image and tries to remove the lighting baked into it. Adobe's Image to Material in Substance 3D Sampler "allows to generate a high-quality PBR material from a single input image" with two algorithms (Substance 3D Sampler documentation: Image To Material):

• AI Powered uses machine learning trained on "fabrics, organics, indoors and outdoor surfaces" to create normal, height and roughness and to remove shadows and highlights from the albedo.
• B2M (bitmap to material) is procedural; it "may produce less accurate results but will work on a wider range of input images".

The result is an estimate. It works well for fairly flat surfaces such as fabric, plaster or paving, and poorly for deep forms such as rocky ground, where the software cannot know what is hidden.

#2. Photo sets under different lights

Keep the camera still and move the light. Each photo shows how the surface responds to light from one direction, which gives much better normals than a single image. Sampler's Multiangle to Material "creates a material from 2 to 8 input images taken under specific light conditions", for example eight photos lit at 0°, 45° and so on to 315°, and outputs base colour, normal, height, metallic and roughness (Substance 3D Sampler documentation: Multiangle To Material). Adobe notes that such lighting can be achieved with a material scanner (Substance 3D Sampler documentation: Multiangle To Material).

#3. Photogrammetry scans

Photograph the surface from many overlapping positions and let software reconstruct real geometry. Poly Haven's published process (Poly Haven Blog: Photoscanned Texture Creation Process):

• Capture "around 300 images per 2 metre square area", spaced as evenly as possible, with measuring tapes for spacing and scale and a colour chart on the same plane as the surface.
• Process RAW files in batch (brightness, white balance, vignetting), avoiding per-pixel edits such as sharpening.
• Reconstruct in RealityCapture: align, build a dense mesh, simplify, unwrap and project colour.
• Bake height, normal and colour onto a flat plane in Blender.
• Make it tile by removing gradients and seams and fixing artefacts.

The core outputs are only three maps, colour (albedo), displacement and normal, because "all the other maps can be derived from" them, saved as "a 16 bit lossless format such as PNG" (Poly Haven Blog: Photoscanned Texture Creation Process).

See photogrammetry for capturing whole objects and photogrammetry and scanning tools for software.

#De-lighting

A photo records the surface and the light that fell on it. A base colour map must contain only the surface. Removing shadows, highlights and gradients is called de-lighting.

You can do it at capture time, in processing, or both:

• At capture: use flat, even light. Poly Haven notes that you can sometimes shoot "on an overcast day or in a shaded area" (Poly Haven Blog: Photoscanned Texture Creation Process). Adobe's capture guide asks for "uniform natural light" (Substance 3D Sampler documentation: 3D Capture: Equipment).
• In processing: correct remaining gradients. In a reply under the article, Poly Haven's Greg Zaal explains that they need 16-bit images "to avoid introducing banding when doing delighting" (Poly Haven Blog: Photoscanned Texture Creation Process).
• In software: single-photo tools such as Sampler's AI Powered mode try to remove shadows and highlights automatically (Substance 3D Sampler documentation: Image To Material).

#Cross-polarisation

Cross-polarisation removes reflections at capture. A linear polarising filter sits over the light, and a second one on the lens is rotated 90 degrees to it. Paul Bourke explains why this works: "shiny surfaces (metals, specular materials) preserve polarisation of the light they reflect", while diffuse surfaces "randomly depolarise" it. So specular reflections are "greatly attenuated" while diffuse reflections still pass (paulbourke.net: Cross polarisation in photography). What reaches the camera is close to pure surface colour. The cost is light: Bourke measured a loss of at least 1.3 stops, usually made up with a brighter source (paulbourke.net: Cross polarisation in photography).

To line the filters up, Bourke photographs a metal spoon in live view and rotates the lens filter until its highlight disappears (paulbourke.net: Cross polarisation in photography).

Poly Haven calls "a cross-polarized flash setup" ideal "for all surfaces to avoid reflections" (Poly Haven Blog: Photoscanned Texture Creation Process). They also recommend taking extra reference photos, especially one showing the surface's specular properties, because cross-polarised photos no longer show them (Poly Haven Blog: Photoscanned Texture Creation Process). You need that reference to set roughness by eye later.

#Scan libraries

You do not always need to scan yourself:

• Poly Haven: textures, HDRIs and models, "all licensed as CC0", usable commercially without attribution (polyhaven.com: License).
• Megascans moved to Epic's Fab marketplace. It was made free to all until the end of 2024, and Epic announced that from 2025 most Megascans content would be paid, with individual assets priced from $0.99 (CG Channel: Epic Games has made Megascans free to all…).

See asset libraries and asset licences before using any library asset in a commercial project.

#How to make one

These steps turn one photo of paving into a tiling material in Substance 3D Sampler. For a measured scan of the same surface, follow Poly Haven's process above instead.

1. Shoot the photo. Photograph a flat patch of paving straight on, in overcast light or shade (Poly Haven Blog: Photoscanned Texture Creation Process), with a tape measure in frame. Aim for a patch about 1 × 1 m that fills the frame, and shoot RAW if you can, because 16-bit sources band less when you correct them (Poly Haven Blog: Photoscanned Texture Creation Process).
2. Prepare the image. Correct white balance and vignetting and crop to the 1 × 1 m area. Avoid sharpening and other per-pixel edits (Poly Haven Blog: Photoscanned Texture Creation Process).
3. Create the material. In Sampler, drop the image in and apply Image to Material. Try AI Powered first; switch to B2M if the subject is unusual, since it "will work on a wider range of input images" (Substance 3D Sampler documentation: Image To Material).
4. Check the de-lighting. Look at the base colour on its own. Remaining shadows or gradients mean more correction, or a better photo (Substance 3D Sampler documentation: Image To Material).
5. Make it tile. Use Sampler's tiling tools to remove seams, then preview the material 3 × 3 and fix any stone that forms an obvious repeat.
6. Set roughness by reference. Compare roughness against a photo that shows the surface's shine, because cross-polarised or flat-lit photos do not show it (Poly Haven Blog: Photoscanned Texture Creation Process).
7. Export at a known size. Export base colour, normal, height and roughness at 2048 px and note that the texture covers 1 × 1 m, which gives 2048 px per metre. See texel density.

#Video tutorials

#Use in recent games

• Call of Duty: Modern Warfare (2019), Infinity Ward. Alongside scanned objects, the team tiled scanned textures to add close-up detail, described as 64 pixels per inch against 16 or 32 in earlier work (Activision Blog: Modern Warfare Initial Intel: How…).
• Assassin's Creed Valhalla (2020), Ubisoft. Terrain and cliffs used scans, the Jotunheim kits used none "except for the barks", and the bark shader blended unique photogrammetry textures at a distance with tiling textures up close (80 Level: A Look at the Material Workflow in Assassin's…). See the example above.
• Star Wars Battlefront (2015), DICE. Location photos were processed to match colours, correct distortion and remove shadows; two boulder textures on Sullust shrank from 55 MB to 3.7 MB when reduced from 4K to 1K (PC Games Hardware: The Making of Star Wars: Battlefront: 100.000…).

#Further reading and watching