How to use the Corona MultiMap?



Corona MultiMap can be used to create a single material, which will show randomized textures (or solid colors), on each object, face, material ID, or based on other modes. The random items are distributed among all the objects using this map. The colors or textures can be blended together using the “Mix amount” parameter.




1. Distribution Modes


Following distribution modes are available:

  • Primitive - each of the items will be distributed on each mesh primitive (triangle):


  • Material - the items will be applied to different materials the MultiMap is assigned to:


  • Instance - each of the items will be distributed on each of the instances (objects):


  • Material ID - each of the items will be distributed based on object’s material ID. In this case, the central teapot uses a material with different material ID than the rest. 


  • Material GBuffer ID - each of the items will be distributed based on material’s GBuffer ID


  • Object GBuffer ID - each of the items will be distributed based on object’s GBuffer ID. In this case, the three teapots in the middle are using different GBuffer IDs than the rest. 
  • Mesh Element - items will be distributed randomly on all mesh elements (in case the mesh consists of multiple elements). 




2. How to use it?


Corona MultiMap can be used in any material slot (diffuse, reflection level, bump, ...). Any type of map, or a solid color, can be used as an item in the Corona MultiMap.


Example usages of the MultiMap include: 


Color variation of tree leaves 

Corona MultiMap was used to produce subtle variation of green between each tree:


Identical colors can be used as both items in the MultiMap. The variation is achieved by increasing the random hue and gamma values:



More distinct variation between the colors can be used to achieve "autumn" look:


Material setup:


Additionally, the frequency of each color version can be controlled using the "Frequency" value:


Result of the above material setup. The red trees are much more frequent than other variants:



"Winter" version of the scene can also be achieved by randomizing the opacity of tree leaves. This way, some of the trees will appear leaf-less:


Material setup:



Texture variation of pebbles


Material setup:



Different textures on floor tiles


Material setup - "Batch load textures..." option can be used to quickly load multiple textures as the MultiMap items:



Note that the CoronaMultiMap can be as well used with one item only. 

You can then use hue and gamma values to randomize the colors. 


Material setup: