That ‘advice’ I gave in the tooltip is just wrong. You can take the “parallax UVs” output and multiply it by another number to tile it more and it will work fine. I am going to fix that wording in the node soon.
Also currently triplanar mapping requires a modification to the tracer. Right now it is transforming the view ray into tangent space. For triplanar POM you will need to do POM three separate times like you guessed.
But it also needs a custom transform for the 2 side faces (XZ and YZ). I think some kind of swizzle operation will work there but I haven’t tested it out yet. is a nontrivial amount of things to add I am not really sure about adding support for it in the node since it would require new inputs and it would probably be so expensive it would be almost guaranteed to get cut from any shipping product.
The simplest way to expose it yourself is to go into the function and find the camera vector that goes into the “world to tangent” transform. Delete that transform and add a new function input called “Custom Camera Vector”. Then you can do the custom swizzles for each of the sides and plug in the different camera vector for each of the tri planar samples.
Actually I just realized somebody made a material function called “TriPlanar Camera Vector”. see if you have it… if so those vectors might work here.