Random colors to geometry node

Question

I started by creating a simple Rubik's Cube and randomizing the colors for each face of the cube by using a geometry node for the single cube. I then added a second object, a plane mesh and made a geometry to grid the cube faster than using an array. As you can see, the same random colors are only applied to the single cube, and the geometry making the grid just duplicates the cube. that I understand why it's not making it random colors for each cube in the grid.

The question I have would be is there a way I can make the colors randomly change on the geometry node that makes the grid, so there is not a recognizable color pattern among the cubes.

Since the Attribute Fill and Attribute Randomizer nodes are no longer in Blender, how can I make that for myself to randomly pick through my materials in the geometry node. Maybe that will work for my random color issue inside the geometry node for the grid. YouTube video link (https://youtu.be/_4HVknkh4es?t=120)

I forgot to mention I have 2 materials. One is the black color material and the other is the color for all the faces of the cube that has random colors. So if it's possible to make only the colors randomly change and not the black material.

Here is the material I have assigned to the faces.


This is the geometry node I put on the single cube to more easily random the colors around on the cube.


This is the grid geometry node I made to array the cube on the second object (plain mesh object).

Answer 1

For demonstration purposes I am going to use a subdivided cube as your Rubik's cube. I have created a simple Rubik's cube, and added a simple shader to it which uses an attribute from geometry nodes.

here is the geometry nodes: If I apply an array modifier or something similar after the geonodes has done it's work, It doesn't know that there are multiple cubes, so it just treats them all as the same cube, and therefore the shader shades them the same. but if you add the array modifier above the geometry nodes in the shader stack it recognizes that the separate cubes have different meshes.

and now it yields it's expected outcome without having to change the grid-making node.

Answer 2

user166113's answer is fine, but here's how I would do it, if I didn't care about the problems mentioned in the commends under the question; I think I'll actually start a new thread on how to randomize a Rubik's cube in Blender, but meanwhile…

If you look at the default UV map of the default cube [left], and create a new color grid [right], you can see four tiles fit into each face, two on each dimension:

While you want three on each dimension ($3×3=9$), so you can create a new color grid, but with default dimensions divided by 2 (now only one tile fits), and then multiplied by 3:

$$ {1024\over2} × 3 = 1536$$

Now 3 tiles fit on each row, but they are cut in half (horizontally) due to how the default UV map is positioned. Either move the UV map by ${1\over12} × {1\over2} = {1\over24} = 0.041667$ to the left or right, or use this offset in the shader:

I marked H7 to be clear what I consider a tile.

The texture was never really needed, just served as a visualization of snapping increments for a noise texture:

UV

For something more complex it's really the same, the extra step being that you e.g. scale the UV to 0 and move it to <1, 1> subdivide the cube, inset individual faces, UV unwrap, count how many square you get per row/column (here 8):

Remember to change the reciprocal in the SNAP from 1⁄₁₂ to ⅛:

Those aren't the colors you want, but you could do something like this to use the color ramp:

Answer 3

you could store a random value on the instances domain as well as one on the face domain (which you kind did already ,ish) and combined them in the shader. Use two attribute nodes and set the one you are using to bring in the instances attribute to instancer.

If you are using cycles (because integers don't really work in eevee so well as of now), then you could just capture the index on both domains (kinda like I said above) and combined them with a combine xyz node in the shader, which you could use as the vector for a white noise.