[1.19] Textures visible on inside faces but invisible on outside faces with OBJ model

Hi. I've created a new block using an obj file and forge's obj loader. While there were some issues I managed to fix, I could not find a way to fix this one. 

The textures of the block on some faces don't show any textures and instead seem to be inverted:

I hope these images are clear enough.

This occurs only on the triangular side faces. The other sides work fine.

I read on this github issue from 1.15.1 that it might be due to inverted vertices on the obj file or some form of culling issue. Since I don't know how to manipulate obj files, I was wondering if this was a common issue to solve. Also, the block does not seem to cast any shadows.

Edited July 30, 20223 yr by tomatosauce