Sets the definition data of the spline surface.
| Name | Type | Description |
| Order | Long | Input Long array of two elements that specifies the order of the spline in U and V respectively. |
| Poles | Double | Input/output Double that specifies the poles of the B-Spline. |
| KnotsU | Double | Input/output Double that specifies the knots of the B-Spline in U. |
| KnotsV | Double | Input/output Double that specifies the knots of the B-Spline in V. |
| Weights | Double | Input/output Double that specifies the B-spline's weights. |
| IsPeriodic | Boolean | Input/Output Boolean that specifies whether the B-Spline is periodic. |