ABCB5DA4

ABCB5DA4
Short name:	NHTG
Long name:	Neighborhood terrain geometry

I have just finished doing all I can to decode this section of a Hood file, I'm hopeless with maths but with a lot of experimenting I have got this:

Description

This resource stores the physical shape of a neighbourhood's terrain, I.E. it's hills and valleys. It also specifies the level of the water table and the terrain type Eg. Desert, dirt, etc.

Format

DWORD

Block ID (Always A4 5D CB AB)

DWORD

Version number

DWORD

Hood Grid size (Always 128)

DWORD

Hood Grid Size (Always 128)

DWORD

Water Table height (Always 00 4C 9C 43)

DWORD

(Length of Following text)

x BYTES

Terrain type (x = length shown above, EG. Temperate, Desert)

8 BYTES

Header? (Always 43 3B 94 6B 01 00 00 00)

DWORD

(Length of Following text, always 8)

x BYTES

Section type (x = length shown above. always c2DArray)

DWORD

First Array Element range (Always 129, X)

DWORD

Second Array Element range (Always 129, Y)

ARRAY[X,Y] = 16641 DWORD

The Array containing the height of the terrain at a given point on the grid. Each Element of the array is made up of a DWORD and represents a point on the Hoods grid starting in the top left and going down, where the DWORD is the height of the terrain at that grid point. There are 16641 DWORDS or 66564 BYTES in this array.

8 BYTES

Header? (Always 43 3B 94 6B 01 00 00 00)

DWORD

(Length of Following text, always 8)

x BYTES

Section type (x = length shown above. always c2DArray)

DWORD

First Array Element range (Always 129, X)

DWORD

Second Array Element range (Always 129, Y)

ARRAY[X,Y] = 16641 BYTE

Each Element of the array is made up of [BYTE] and represents a point on the Hoods grid starting in the top left and going down. There are 16641 BYTES in this array. These values are always 0.

Notes

The 00 00 00 00 point for the terrain hight value is effectively at the core of the Sims 2 planet.

The water is set at a height of 43 9C 40 00.

The default terrain level is 43 A8 C0 00.

The minimum level for the terrain to dip to is approx. 40 10 C0 00.

The Sims 2 Hood is made up of 128 rows and columns, which yields 129 x 129 control points.

When you load a freshly created Hood the first element in the DWORD array points to the Top left point (corner of the square). The second element points to the next one down towards you. When you get to the bottom (element 129) you go back to the top and start coming down the second coloumn.

Overview of format

Here is a sample of an actual Hood, that I made. It was completely flat with nothing on it at all. I used a blank default SC4 City to generate it so all values are at their defaults:

  A4 5D CB AB 04 00 00 00     <<Always the same
  80 00 00 00     <<Hood Grid Size. Always the same, 00 00 00 80 = 128.
  80 00 00 00     <<Hood Grid Size. Always the same, 00 00 00 80 = 128.
  00 40 9C 43     <<The water table height. Always the same
  09 00 00 00     <<Length of following text
  54 65 6D 70 65 72 61 74 65    << The Terrain Type, spelt out, in this case  "Temperate".
  43 3B 94 6B 01 00 00 00   <<Always the same.
  08 00 00 00     <<Length of following text. Always the same.
  63 32 44 41 72 72 61 79       <<Always the same, spelt out, "c2DArray".
  81 00 00 00     <<Array size X, Always the same, 00 00 00 81 = 129.
  81 00 00 00     <<Array size Y, Always the same, 00 00 00 81 = 129.
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43
  00 C0 A8 43  00 C0 A8 43  00 C0 A8 43     <<There are 129 blocks like this Each 4 bytes make up a DWORD.  In a "real"
                                              Hood these values are all different representing the various terrain heights.
  ...
  ...
  43 3B 94 6B 01 00 00 00   <<Always the same
  08 00 00 00     <<Length of following text:
  63 32 44 41 72 72 61 79      <<Always the same, spelt out, "c2DArray".
  81 00 00 00     <<Array size X, Always the same, 00 00 00 81 = 129.
  81 00 00 00     <<Array size Y, Always the same, 00 00 00 81 = 129.
  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  00 00 00 00 00 00 00 00 00 00 00 00 <<There are 129 blocks like this. Always the same, 00.
  ...
  ...