cls_atk_xxx.2da are made up of 3 default definitions for the base attack bonus progression. These are used in the AttackBonusTable column in classes.2da.
The default files are:
- cls_atk_1.2da - High +1/level (Fighter) attack progression
- cls_atk_2.2da - Medium +3/4 level (Cleric) attack progression
- cls_atk_3.2da - Low +1/2 level (Mage) attack progression
If you multiclass you look up in all relevant tables. A "low attack" class of 5 levels would be +3, and if they had a "high attack" class of 3 levels it'd be +3 so +6 total (meaning additional attacks as well). All this is calculated automatically.
Epic Levels
While they define progression up to level 60, after level 20 Epic BAB progression is used instead (1 every 2 levels). The 60 levels would have been more relevant in pre-expansions since the base game did not have codified epic levels, but NPCs could be given multiple classes and higher than level 20.
2da Columns
| Column | Example Contents | Valid Values | Description and Notes |
|---|---|---|---|
| BAB | 4 | Integer | The amount of BAB to get at that level based on the row ID column. Note that since the ID row starts at 0, level 1 of a class would be row 0 (eg: value of 1 for the cls_atk_1.2da file). |
2da Contents
cls_atk_1.2da
2DA V2.0
BAB
0 1
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
10 11
11 12
12 13
13 14
14 15
15 16
16 17
17 18
18 19
19 20
20 21
21 21
22 22
23 22
24 23
25 23
26 24
27 24
28 25
29 25
30 26
31 26
32 27
33 27
34 28
35 28
36 29
37 29
38 30
39 30
40 31
41 31
42 32
43 32
44 33
45 33
46 34
47 34
48 35
49 35
50 36
51 36
52 37
53 37
54 38
55 38
56 39
57 39
58 40
59 40
cls_atk_2.2da
2DA V2.0
BAB
0 0
1 1
2 2
3 3
4 3
5 4
6 5
7 6
8 6
9 7
10 8
11 9
12 9
13 10
14 11
15 12
16 12
17 13
18 14
19 15
20 16
21 16
22 17
23 17
24 18
25 18
26 19
27 19
28 20
29 20
30 21
31 21
32 22
33 22
34 23
35 23
36 24
37 24
38 25
39 25
40 26
41 26
42 27
43 27
44 28
45 28
46 29
47 29
48 30
49 30
50 31
51 31
52 32
53 32
54 33
55 33
56 34
57 34
58 35
59 35
cls_atk_3.2da
2DA V2.0
BAB
0 0
1 1
2 1
3 2
4 2
5 3
6 3
7 4
8 4
9 5
10 5
11 6
12 6
13 7
14 7
15 8
16 8
17 9
18 9
19 10
20 11
21 11
22 12
23 12
24 13
25 13
26 14
27 14
28 15
29 15
30 16
31 16
32 17
33 17
34 18
35 18
36 19
37 19
38 20
39 20
40 21
41 21
42 22
43 22
44 23
45 23
46 24
47 24
48 25
49 25
50 26
51 26
52 27
53 27
54 28
55 28
56 29
57 29
58 30
59 30