LodSection

LodSection
{
 ulong FaceIndexBounds[2];     // lower vs upper (NoOfFaces in this section = (FaceUpperIndex - FaceLowerIndex) / 8
 ulong MaterialIndexBounds[2]; // ODOLV4x only
 ulong FaceUserValue;          // see P3D Point and Face Flags
 short TextureIndex;           // as per Face struct
 ulong FaceFlags;              // see P3D Point and Face Flags as per Face struct
 ///////// // ODOLV4x only//////
 long  MaterialIndex;
 if MaterialIndex ==-1
 {
   byte ExtraByte;
 }
 ulong UnknowLong;             // generally 2
 float UnknownResolution;
 float UnknownResolution2;     // generally 1000.0
 ////////////////////////////////
}

a Material or Texture index with default value (-1) has no face/material associated with itand consequently the bounds are zero

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