I am doing a project where I have 2 objects a chameleon and unit cell. The idea behind changing chameleon color is that distance between cells is reduced so light reflets a different color each time the cell either shrinks or expands. I want to model this. Now I have unit cells where I change the expansion and contraction but I do not know how to connect it to the chameleon so every time I expand the cells the color of chameleon changes. How to link them as the material is in shader while the expansion occurs in geometry nodes. please help!
I think the easiest way would be to use an empty to drive both your GN setup for the cells and the material. Use the scale of the empty as a driver for the materials colour (Hue in the HSV node) and use that same driver to change the expansion/contraction of the cells in your GN setup.
I do not know your GN setup but here is a simple example, scale the empty to see the result. I just changed the scale of the sphere in the example with a simple GN setup you would have to adapt it to your setup.