This document describes the binary format of the Terrain.MaterialColors property.
The format of the MaterialColors property is a constant-sized array of colors. Each group of 3 bytes represents a Color3 value corresponding to a particular Material enum item. Not all materials are represented. The 3 bytes in a group correspond to the red, green, and blue components of the Color3, respectively. The first two groups in the array appear to always be zeroed.
The following table lists the nth byte in the sequence, in decimal format. Each
row corresponds to a particular material, and the columns indicate the red
(RR), green (GG) or blue (BB) component of the material's color:
RR GG BB
00 01 02 (reserved)
03 04 05 (reserved)
06 07 08 Grass
09 10 11 Slate
12 13 14 Concrete
15 16 17 Brick
18 19 20 Sand
21 22 23 WoodPlanks
24 25 26 Rock
27 28 29 Glacier
30 31 32 Snow
33 34 35 Sandstone
36 37 38 Mud
39 40 41 Basalt
42 43 44 Ground
45 46 47 CrackedLava
48 49 50 Asphalt
51 52 53 Cobblestone
54 55 56 Ice
57 58 59 LeafyGrass
60 61 62 Salt
63 64 65 Limestone
66 67 68 Pavement
For example, the 34th byte indicates the green component of the Sandstone material's color.