Extract Isocurve


This topic will explain where to find the Extract Isocurve function, andexplain the options found in it.This topic will also give quick steps, an example, and provide links to related topics.

The Extract Isocurve Function

The Extract Isocurve function creates wireframe curves with a constant U and/or V value ona selected surface.The user is also able to control the placement of the curves by adjusting the percentage values in the parameters or free hand by using  mouse location.

U and V

These directions should be thought of as directions rather than axes.The more complex the surface is, the more complex the u and v curves, but each will always be perpendicular to the other at every given point: 

To open Extract Isocurve:

  • In the Utilities group, of the Create 2D ribbon, clickExtract Isocurve.

The parameters display in the Data Entry Manager.

The Data Entry Parameters

The function is performed using only geometry selection.

Selected Geometry


(Delete) - removes the highlighted item from the list.

The list box will list the entity currently selected for the function.


  • U - creates geometry along the U direction of the surface.

  • V - creates geometry along the V direction of the surface.

  • Both Directions - creates geometry along the U and V directions of the surface.

Position %

  • U % - determines the location of geometry creation on the surface from one end to the other.

  • V % - determines the location of geometry creation on the surface from one end to the other.


When extracting the isocurves, you are able to extract the untrimmed version of the isocurves.The surfaces retain the information of their untrimmed state and curves can be extracted based on this.In the trim example images below, notice when the isocurves are not trimmed they extend to the edge of the surface in its untrimmed state.

Rectangular Surface Trimmed Surface

  • Trim Isocurves

    - Isocurves are trimmed at surface edges.

    - Isocurves are able to extend beyond surface edges.

  • OK - finalizes the function.

  • Cancel - exits the function.

Quick Steps - Extract Isocurves

  1. When the function is open the Selected Geometry list automatically has focus.

    Select the surface you to extract the isocurve from.

    The geometry is added to the Select Geometry list and the preview appears.

  2. Update the directions to extract the isocurves from.

  3. Adjust the position of the curves with your mouse in the graphics area, or by specifying values in the Position % group.

  4. In the Options group, decide whether to trim the isocurves or not.

  5. Click OK to confirm the result.

  6. Repeat this process as needed for any other isocurves to be extracted.

  7. To close the function, click Cancel.

Example - Extract Isocurve

  1. In the Quick Access Toolbar, click New.

  2. In the Primitives group, of the Create 3D tab, click Sphere.

    The preview appears.

  3. Leave the default values as they are and click OK.

    The sphere is created.

  4. In the Shapes group, of the Create 2D ribbon,click Rectangle.

    The sketch handles of the sphere function disappear.The preview of the rectangle appears.

  5. Update the Dimension group values to Length 1.000, Width 1.000.

  6. Update the Base Point Z value to 1.000.

  7. Click OK.

  8. At the bottom right of the screen, click the down arrow next to the current color.

    Color options appear.

  9. Select Black.

    The color options disappear.

    The result of our projection will now be black.

  10. In the Utilitiesgroup, of the Create 2D ribbon, click Project Curves.

    The rectangle preview disappears.

  11. Hover over an entity of the rectangle, hold shift and click the entity to select the entire chain.

    The entities are added to the Select Curves to Project list.

  12. Click in the Select Surface/Solid list to give it focus.

  13. Highlight the sphere and click it to add it to the list.

  14. Click OK.

  15. Click Cancel to exit the function.

  16. In the document toolbar, click to enter into selection mode.

  17. Select the sphere.

  18. Delete the sphere.

Note: If the surface being projected to has two sides,meaning that it passes twice directly underneath the curves to be projected,the curved will project onto both sides just as in this example.If itpasses 3 or more times, the curves will project onto the surface as manytimes as it passes underneath.Normally only one projection is necessary,so if more are generated then the extra projections should be deletedfrom the drawing.

Related Topics

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