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Textured objects often show obvious repetitions, which instantly give away that the scene is computer-generated. You can use the Corona MappingRandomizerMapping Randomizer to quickly randomize textures on multiple objects or object parts, making the image appear more realistic.

The Corona MappingRandomizerMapping Randomizer allows you to apply random offset, rotation, and scaling to textures and procedural maps assigned to different objects, or even to a single object. The way it works is similar to the Corona Multimap. For example, you can randomize a wood texture applied to a set of planks so that each plank has a different look in your final render. You can also apply a blending effect to the randomized texture tiles, which makes them appear even more natural.

To enable the UVW mapping randomization, plug any texture (be it a bitmap or a procedural map) into the Corona MappingRandomizerMapping Randomizer input slot and then plug its output into any material property. You can then adjust the texture transformations and other options to the desired values. You can use the Corona MappingRandomizerMapping Randomizer with any material property, including grayscale bump maps, RGB normal maps, and displacement.

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Randomize by

Primitive – Randomizes by different primitives which are triangles, hair strands, particles, etc.
Sub-primitive – Randomizes by different sub-primitives, which are displacement microtriangles or hair segments.
Polygon – Randomizes by different polygons, which are groups of triangles (e.g. quads).
Mesh Element – Randomizes by different connected mesh elements, which are groups of triangles connected by edges.
Decal – Randomizes by different distinct decal objects. This randomizes only the decal layer, not the object it is projected onto. Note that this tracks decals by their names, so the result changes if a decal is renamed.
Tile ID – Randomizes by different tiles if Corona Tile Map is used.
Instance – Randomizes by different scene objects (or instances in a scatter object). This tracks objects by their names, so the results change if an object is renamed.
Material GBuffer ID – Selects map with index equal to the hit material G-Buffer ID.
Object GBuffer ID – Selects map with index equal to the hit object G-Buffer ID.
Material name – Randomizes by different assigned materials.

Face Material ID – Selects map with index equal to the hit face material ID.

W|Z – Specifies the minimum (From) and maximum (To) allowed texture rotation in the Z coordinate with a custom increment (Step).

Instance

Mapping Randomizer is randomized per each

instance (

object).

Material ID

Mapping Randomizer is randomized based on the object's material ID. In this example,

every floorboard has a different, randomly assigned material ID.

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Material GBuffer ID

Mapping Randomizer is randomized based on the material's GBuffer ID. In this example, each cube has a different material assigned, and each of those materials has a different Material GBuffer ID assigned

Instance

.

Object GBuffer ID

Mapping Randomizer is randomized based on the object's

GBuffer ID. In this example,

each cube object has a different

GBuffer ID assigned (select object > right-click > object properties > GBuffer ID).

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Mesh Element

Mapping Randomizer is randomized per each mesh element

Material GBuffer ID

. In this example, each

floorboard is a separate mesh element.

Polygon

Mapping Randomizer is randomized per mesh face

Object GBuffer ID

. In this example,

each floorboard is a single mesh element.

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Without the

Corona Mapping Randomizer

, the textures are repeated on each of the steps in a very obvious way.

We can easily fix that: the first step is plugging the diffuse texture into the Corona

Mapping Randomizer map and setting its U and V offset values to 0 - 1. This enables the randomization of the texture's maximum offset in both axes by its full width and height.

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The remaining issue is that the textures are aligned in the wrong direction. Since the

Corona Mapping Randomizer

relies on

mapping randomizing (as the name implies), to fix that, we can use any preferred method of rotating the textures - for example, the UVW Xform modifier or changing the rotation directly in the Bitmap texture's properties. In this case, a UVW Xform modifier was applied to rotate the texture by 90 degrees.

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We can start with a few objects using a brick wall texture with no randomization whatsoever.

In this case, we want to randomize the U and V positions per object, but we also want to have them tiled on every single object in a random way. This can be easily done with the

Corona Mapping Randomizer.

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Note that in addition to U and V offset variation, we also enabled the Randomize each tile option and set Number of tiles to 4. This tiles the texture on each surface it is applied to, and the tiling is then randomized using the offset, rotation, and scale values.

The remaining issue here is that while the randomization works excellent, the bricks are not aligned in straight horizontal rows anymore because of the full V offset randomization.

We can fix that by enabling the Step option next to the V Offset. The Step value decides about the interval at which the texture is moved. Leaving it at 0 results in unrestricted, random movement. Setting it to 1 means that we only allow the offset to be 1, 2, 3, and so on, resulting in no visible randomization whatsoever. Setting the value to 0.5 allows offsetting the texture by half its height, and so on. In this case, a single segment of our brick wall texture consists of 7 rows of bricks. To calculate the desired Step value, we need to divide 1 by the number of rows or columns. In case of our brick wall 1 / 7 = 0.143, so let's use this value.

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As you can see in the above image, the bricks are still randomized, but at the same time they are always arranged in horizontal rows thanks to the 0.143 Step value. 

The last thing left to do in our brick material would be adding displacement to it since that is also possible with the

Corona Mapping Randomizer

. Clone the

Corona Mapping Randomizer map, so that the diffuse texture and displacement texture randomization is the same, plug the grayscale displacement map into it, and plug the result into the material's displacement slot.

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