Polybrush Texture Painting for Unity 2018

I have a pretty giant VR project that I have been working on over the past couple of years made in Unity 2018. Over the past couple of days, I realized that Polybrush would be the perfect solution to quickly making a bunch of giant floating island models which I need.

HOWEVER, it seems that Polybrush texture painting doesn’t work in 2018 as it says “It doesn’t look like any of the materials on this object support texture blending!” I’ve tried importing shaders from both the 2017 and 2019 versions of Polybrush, but those don’t work in 2018 apparently (also I don’t really know much about shader writing, so I couldn’t even begin to try to fix it).

Is there any way I can get Polybrush texture painting to work in 2018, or am I just boned?

Thanks in advance.

have you found a solution? I’m in a similar pickle.