| Offset | Name | Size | Contents |
| 4 | grbit | 2 | Option flags |
| Offset | Bits | Mask | Name | Contents | ||
| 0 | 0 | 01h | fFillSurface | 1 = chart contains color fill for surface | ||
| 1 | 02h | f3DPhongShade | 1 = this surface chart has shading | |||
| 7–2 | FCh | (reserved) | Reserved; must be zero | |||
| 1 | 7–0 | FFh | (reserved) | Reserved; must be zero | ||
| Offset | Name | Size | Contents |
| 4 | grbit | 2 | Option flags |
| Offset | Bits | Mask | Name | Contents |
| 0 | 0 | 01h | fFillSurface | = 1, chart contains color fill for surface |
| 0 | 7–1 | FEh | (reserved) | Reserved; must be zero |
| 1 | 7–0 | FFh | (reserved) | Reserved; must be zero |