t3d to obj v0.1 (c) 2020 mar
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export the t3d as is, no intersecting world with huge brush,
no "transform permanently" (it destroys uv mapping anyway),
just UnrealEd/export/t3d
(assuming t3d is compatible with old Unreal/UT99/old Deus Ex)

usage: t3d_to_obj.exe input.t3d

will create obj + mtl files in the same path as input
obj file scale is in metres

note that only world geometry is exported, movers are skipped

for precise uvs, it's necessary to put referenced textures in pcx/png format
in t3d_tex subfolder relative to current working directory
this is necessary because old Unreal didn't use normalized UVs
(old engines used SW rasterization)
any missing textures will be assumed 128x128

the obj file doesn't contain any normals/smoothing groups,
so some postprocessing may be necessary

also the faces are exported as convex polygons with T-vertices added,
so post-triangulation may be needed

up to 3 groups will be created:
structural (can be used for world BSP/portal visibility)
detail (semisolids and nonsolids)
detail_bothsided (bothsided detal polys)

the process should take seconds to tens of seconds, depending on map complexity
(Bluff eversmoking takes ~19 seconds on my rig)

enjoy
