Page History

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

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

To enable the randomization, plug any texture (be it a texture map or a shader) into the Corona Mapping Randomizer shader 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 Mapping Randomizer shader with any material property, including the bump channel, RGB normal maps, and displacement.

Level – Defines the intensity of the entire shader parameters.

Color – Sets a solid color to use as the source.

Texture – Sets either a texture map or a procedural shader to use as the source.

Mix mode – Defines how the texture map or shader combines with the color Color parameter.

Mix value – Defines the percentage of the texture 's percentage that is mixed with the color Color parameter. It works like opacity for the shader's texture.

Randomize by – This parameter allows to select Selects between different randomization modes.

Primitives – This mode randomizes Randomizes the texture map or shader by different primitives which are triangles, hair strands, etc.
Sub-primitive – Randomizes by different sub-primitives, which are displacement micro triangles or hair segments.
Material name – This mode randomizes Randomizes the texture map or shader by different assigned materials. Materials The materials must have different names.
Objects – This mode randomizes Randomizes the texture map or shader per each object. You can even use this mode with cloner Cloner objects.
Material tag index – This mode randomizes Randomizes the texture map or shader based on the object's material tag position. Polygon selection tags should can be used in combination with this mode for each material tag assigned.
Material ID – This mode randomizes the Randomizes the texture map or shader based on the Material's ID. The material Material ID can be located and set in the Advanced properties for each material.
Object buffer ID – This mode randomizes Randomizes the texture map or shader based on the object's buffer ID. The buffer ID can be located and set in the Corona Compositing tag for of each object.
Mesh Element – This mode randomizes the texture map or shader by different connected mesh elements, which are groups of polygons connected by edges.
Polygon – This mode randomizes Randomizes the texture map or shader by different polygons, which are groups of triangles (e.g. quads).
Decal – This mode randomizes Randomizes the texture map or shader 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 – This mode randomizes Randomized by different tiles if Corona Tile Map is used.
Multiple properties – This mode allows Allows using different randomization modes at the same time.

Seed – This value makes random permutations of the UVW randomization results.

Offset

U From – This parameter sets Sets the initial position of the shader texture in the U coordinate for the shader's texture.

U To – This parameter sets Sets the maximum end position that of the shader 's texture can use for in the U coordinate. The shader can randomly use any value between the U From and U To parameters.

U Step – This parameter lets you decide Determines the offset 's increment for each texture variation in the U coordinate for each texture variation. It works like the Quantize Move Step tool in Cinema 4D.

V From – This parameter sets Sets the initial position of the shader texture in the V coordinate for the shader's texture.

V To – This parameter sets Sets the maximum end position that of the shader 's texture can use for in the V coordinate. The shader can randomly use any value between the V From and V To parameters.

V Step – This parameter lets you decide Determines the offset 's increment for each texture variation in the V coordinate for each texture variation. It works like the Quantize Move Step tool in Cinema 4D.

Rotation

W From – This parameter sets Sets the initial rotation of the shader texture in the W coordinate for the shader's texture..

W To – This parameter sets Sets the maximum end rotation that of the shader 's texture can use for in the W coordinate. The shader can randomly use any value between the W From and W To parameters.

W Step – This parameter lets you decide Determines the offset 's increment for each texture variation in the W coordinate for each texture variation. It works like the Quantize Rotate Step tool in Cinema 4D.

Scale

U From – Sets the initial scale of the shader texture in the U coordinate for the shader's texture.

U To – Sets the maximum end scale that of the shader 's texture can use for in the U coordinate. The shader can randomly use any value between the U From and U To parameters.

U Step – This parameter lets you decide –Determines the offset 's increment for each texture variation in the U coordinate for each texture variation. It works like the Quantize Scale Step tool in Cinema 4D.

V From – Sets the initial scale of the shader texture in the U coordinate for the shader's texture.

V To – Sets the maximum end scale that of the shader 's texture can use for in the V coordinate. The shader can randomly use any value between the V From and V To parameters.

V Step – This parameter lets you decide Determines the offset 's increment for each texture variation in the V coordinate for each texture variation. It works like the Quantize Scale Step tool in Cinema 4D.

V scale same as U – When enabled, this lets you use a uniform scale factor for the randomization (same value for U and V coordinates)the V and U axis use the same values for scale, rotation and offset. If this checkbox is not active, it allows you to set different scale values for each axisaxes.

Randomize each tile – This parameter When enabled, tiles the texture on each surface it is applied to, and is randomized using the offset Offset, rotation Rotation, and scale Scale values.

High quality blending – This option is enabled by default and results in a better quality of the random tile blending, at some performance cost. The specific performance impact depends on the material's complexity. In case of visible rendering slowdown, it is advised to disable this option.

Number of tiles – This parameter sets the number of tiles to be randomized when the Randomize each tile checkbox is enabled.

Blending – This parameter controls how the individual tiles of the randomized texture are blended with each other. Higher blending further blends values blend the tiles further together and makes make the texture appear slightly more blurry and uniform. Lower blending values reduces reduce the areas where the tiles are blended together and makes make the texture sharper.

Primitives

The mapping Mapping is randomized per each mesh primitive (triangle)

Objects

Mapping is randomized per each instance (object).

Image Added

Image Removed

In the previous examples, we always used the Corona Mapping Randomizer with some sort of defined UVW mapping (e.g. the object was created with its own mapping). In the case of objects with In cases where objects have no UVW mapping channel, or ones that are hard to properly unwrap (, such as complex organic forms), an ideal solution is to combine the UVW Randomizer with the Corona Triplanar shader.

Here we can see a duck model covered with a checkerboard patterned texture map using the Corona Mapping Randomizer. Since the Mapping Randomizer relies on UVW mapping, in case of incorrect mapping (like in this case), we can see artifacts such as texture stretching and seams.

To fix that, we can connect the Corona Mapping Randomizer shader to a Corona Triplanar shader (not the other way around, as the Triplanar shader overrides all mapping data coming after it!) Triplanar shader and connect the result to the desired slot (, in this case the diffuse color). This lets us take advantage of the superpowers of both the Mapping Randomizer and the Triplanar shaders. Thanks to the Mapping Randomizer, the texture is randomized in terms of offsetOffset, scalingScaling, and rotationRotation, and it is using random tiling. Thanks to the Corona Triplanar shader, there is no stretching or seams, and the texture is uniformly distributed over the object's surface.over the object's surface.