Hi @mrkarate,
Just to understand correctly, how are you going to select that pixel? Are you talking about doing raycasting to find a point on the model and from there translate that to a UV coordinate to get the pixel color?
There is this example (not working on current PlayCanvas Engine, you will have to run it using an earlier version), by @FBplus:
And also this character damage PlayCanvas example: https://developer.playcanvas.com/en/tutorials/character-damage-demo/
Both example do partially what you are looking for, that is to convert a world point to a UV coordinate. They paint that to a render target to apply color/damage to the model. I’m not sure if that’s useful for you here, just sharing it with you.
On the other hand if you are looking to get the color of a selected (e.g. clicked) pixel, then you can easily do that by rendering the active camera to a render target and then reading that render target at the exact screen coordinates you clicked. That will give you the pixel color.
The PlayCanvas picker does something similar to find the selected entity: https://developer.playcanvas.com/en/tutorials/entity-picking/
Hope that helps.