Using additional conversion options (More Options)

Depending on the method you have selected in the Fix drop-down list, different options will be available under the More Options node of the Convert Surface to NURBS command.

Fix set to Tolerance Fix set to Parameters Fix set to Advanced

Specialized conversion Enables you to control the type of the resulting NURBS surfaces.
  • When this box is selected surfaces are converted to specialized NURBS. Specialized NURBS are much more accurate and have a lower number of control points. See "Specialized conversion" for details.
  • When the box is cleared, surfaces are converted to non-specialized NURBS.
     
Keep initial degree This check box is active only when the Continuity order is set to Maximum.
  • When selected, the resulting surface will have the same degree as the original one.
  • When not selected, the resulting surface degree may differ.
     
Keep original domain Enables you to control the domain of the resulting entity.
  • When this check box is selected, the domain of the resulting entity will have the same size as the one of the original entity.
  • When not selected, the domain of the resulting entity may differ from the original (and be smaller).
     
Use initial no. of arcs
  • When the box is checked, you can perform the conversion based on the number of arcs of the entity to convert: this number is added to the specified maximum number of arcs, so as to have a more coherent result for each surface.
  • When the box is cleared, the initial number of arcs of the entity to convert is not taken into account.
     
Update deviation Enables you to control the precision of the resulting surfaces.
  • When this check box is not selected, the resulting entity will keep its own local precision value.
  • When selected, the achieved precision will be assigned to the local precision of the resulting entity.
     
Output type Enables you to select the output type for the resulting surfaces.
Standard To convert the selected surfaces without splitting them.
Single-patch surfaces To convert the selected surfaces by splitting them into as many single-patch surfaces as required.
Bezier surfaces To convert the selected surfaces by splitting them into as many Bezier surfaces as required (that is, single-patch surfaces for which the U and V parameters vary in the range [0,1]).

Some notes about the choice of the output type
If the Fix mode is set to Tolerance, the Specialized conversion option is grayed out when the Bezier surfaces output type is selected because it would generate rational NURBS, which cannot be split into Bezier surfaces.
The splitting options cannot be applied to associative surfaces, as from one initial surface you get several ones, causing the new surfaces to have the current color. Apart from the color the generation of the new surfaces depends on the current value of the Base entities drop-down list in the General category of the Document Properties. When the Modify option is selected, associative surfaces are not deleted but simply hidden.