[zookeeper]

I'm not too familiar with smoothgroups TBH, but from what I've read, the smooth modifier applied to the whole mesh is the same thing as using different smoothgroups with identical properties.

Yes, manual smoothing and using the smooth modifier should really result in the same thing (except for possible differences in the smoothing group distribution, obviously).

Anyway, I took a look at your .max file and the geometry does have some problems. Just apply an STL check modifier and you should find plenty of open edges... I didn't have time to check how to fix them, as simply welding all vertices with a low threshold didn't do the trick. Whether those problems cause the problem when there's smoothing groups used, I don't know.

[mjn.mixael]

I came up with the same results. Look into those holes and see if that fixes the problem.

[Kusanagi]

Alright, I'll look into it here and keep you all updated Thanks for looking at it!

Edit: It helped a lot, but unfortunately, didn't solve the problem entirely. Welding the vessel then running the STL check showed the problem faces - a quick Cap Holes and applying an invisible texture fixed all the STL errors. The smoothing worked well, but there are still areas where you can fly through the ship and you can fly through the antennas almost completely. I think this may have to do with the BSP data being generated from the smoothgroups over such a large area with such a low-poly mesh.

Looks like most of the lighting will be ambient then, to cut down on the glare of the models since there's no way to make them smooth without breaking their collision, even if the STL check returns no holes or other errors in the model

[Kusanagi]

Tried a few other things and still no go. Oh well, guess we'll just have to be creative with the lighting.

[mjn.mixael]

Make sure your normals are all facing the right way too.

[Kusanagi]

They are. If I take the exact same model and have no smoothing, there's no collision errors. Same model with smoothing - collision breaking around corners or where several polies come together. About halfway down the mothership antennas you can fly and shoot through them, while at the base they're fine.

I guess smooth groups end up causing problems nobody thought of, because they've never been applied to lower poly models. I'd be interested to see if the same thing happens if the smoothing is done on a low-poly retail ship with a lot of sharp edges like the Cain or the Azrael.

[Col. Fishguts]

Are the antennas separate submodels or part of the main mesh? Collision detection only works within the bounding box of the main mesh (of any of the LODs)

[Kusanagi]

Main mesh. The mothership has no subobjects, as the door is a separate model completely.