For quick Prototyping, I'm using the SideFX Labs Color Gradient node. It works great for normal boxes or other meshes. In Houdini, it also works but when I import the HDA to Unreal the object stays white. The objects where it doesn't work are CopyToPoint Instances with a lot of Cubes. IT also doesn't wor with the normal color mode or Side FX QuickMaterials.
Hi make shure to store the Color as Vertex-attriute. The Labs Color Gradient stores Cd as Pointattribute, so you need to promote it to Vertex and also have a Vertex Color Node in your UE4-shader. I am not shure about Instances though. greetings