By working with BPS, I've come across this sort of weird bug that is happening in my map, maybe I'm doing something wrong but part of the the meshes doesn't seem to properly disappear to make a hole:
This seems to happen with wall meshes that aren't perfectly perpendicular, although I haven't verified yet.
I'm afraid the BSP is not completely bug free - so these will happen now and then 😔
the thing is it's a technique that was never really meant to be used dynamically and it's hard
to predict what might cause an error (something to do with floating point errors adding up as the tree grows)
my only workaround (or recommendation) is to use multiple groups when you can
(of course there might be some other cause - I cannot tell for sure without looking a the map itself)
I tried replicating the BPS bug within a test map to see if this was something that specifically happened in sloped walls. Seems like the BPS work fine for the most part here:
The most obvious bug is at certain moments some meshes of the BPS will outright disappear for no apparent reason:
Seems like the real problem happen in my large map, where all the meshes that are supposed to disappear just remain in the carved hole, which doesn't seem the case in other maps I've made, and I don't understand how to possibly solve this issue.
I'm afraid it's completely random (seemingly at least) sometimes it works great - sometimes don't 😔
one solution is to set your original wall to have the 'noexport' texture and make another room next to it in a different BSP group (with it's wall facing inwards also 'noexport')
in other words when the BSP fails there is no other choice but do a little manual carving (at least to glue two groups together)
