Analyzing Surface Curvature

You can assess the curvature of a surface.

Note: Depending on your role, you may not have access to this functionality.

Before you begin:
  • Open an existing 3D shape.
  • Set the discretization to a maximum: Select Me > Preferences > Common Preferences > 2D 3D View Display > Performance, 3D Accuracy section, select Fixed and enter a value of 0.01.
  • Disable the highlight of geometry selection: Select Me > Preferences > Common Preferences > 2D 3D View Display > Selection > Selection section, clear the Highlight faces and edges check box.
  • Select Me > Preferences > App Preferences > 3D Modeling > Styling > Freestyle Shape Design, General tab, Mapping Analysis option section, and select No warning message if material mode is not ON.
Note: If the 3D Accuracy parameter does not generate enough visualization tessellation triangles, for flat surfaces, for example, specify a low number of generated isoparametric. In Me > Preferences > Common Preferences > 2D 3D View Display > Performance > Miscellaneous section, select Enable isoparametric generation and enter a low value for the Number of isoparametric in U and V parameter. The generated isoparametric are considered as the base line for the visualization tessellation mesh and have therefore an influence on the surfacic curvature computation results.
  1. From the section of the action bar, click Surfacic Curvature Analysis .
  2. In the Type area, select Gaussian.
  3. Select a surface.
    The surface is painted according to the color scale in the dialog box.

  4. Adjust the color scale: In the Color scale dialog box, click Use Min Max.
    • The maximum and minimum values in the dialog box are specify according to the values detected on the surface.
    • The analysis colors are updated to match the color scale in the dialog box.


  5. Show gaussian curvature information on all parts of the surface:
    1. In the Options area, click On The Fly .
    2. Move the cursor over the surface.
    At the position of the pointer, the following information is displayed:
    • The local gaussian value of the curvature ( The Gaussian type is selected in the Type area).
    • The direction of the maximum curvature.
    • The direction of the minimum curvature.
  6. Show minimum/maximum/mean curvature information on all parts of the surface:
    1. In the Type area, select Minimum, Maximum, or Mean.
    2. Move the cursor over the surface.

    At the position of the pointer, the following information is displayed:

    • The local minimum, maximum or mean value of the curvature (according to your selection in the dialog box).
    • The local radius of curvature or mean radius of curvature (according to your selection in the dialog box).
    • The direction of the maximum curvature.
    • The direction of the minimum curvature.


    Important: The color scale does not change when you switch from one analysis type to another analysis type (except for Limited and Inflection Area types), or to another element. This facilitates comparison of curvature because each analysis or element can be viewed using the same reference colors and values.
  7. Show the position of the maximum and minimum values:
    1. In the Options area, clear On The Fly .
    2. Click Show MinMax .
    The position and value of the maximum and minimum values is displayed.

  8. Define a radius limit and reduce the number of colors in the color scale:
    1. In the Type area, select Limited .
    2. In the Options area, click On The Fly .
    3. In the Limited Radius options area, enter the radius value or use the arrows to change it.
    The values in the color scale dialog box are updated automatically.

    Minimum curvature and radius values are displayed.



  9. In the Type area, select Inflection Area.

    This analysis enables you to identify the curvature orientation:

    • Green: Areas where the minimum and maximum curvatures have opposite orientations.
    • Blue: Areas where the minimum and maximum curvatures have the same orientation.


    Note: Inflection lines created during Inflection Lines analysis are always created within the green area.
  10. In the Type area, select Symmetric Gaussian. Select the required parameters.
    1. In the color scale dialog box, click Use Max:

      • The maximum value in the dialog box is specified according the values detected on the surface. Zero Threshold is not modified unless it becomes larger than Max Value.
      • The analysis colors are updated to match the color scale in the dialog box.
      Note: You can also manually enter the values.

    2. Select one of the following options under Color Scale Variant area:

      • Body: specifies the zero threshold at 0.00000002 and the max at 0.0000004.
      • Default: specifies the zero threshold at 0.0000000001 and the max at 0.0001.

      The result is the same as the result for the Gaussian type.

    The color range contains 11 colors on the positive side, 11 colors on the negative side, and pink color indicating zero in the middle.
    Note: To change the total number of colors, right-click any of the color icons, select Number of Colors, and enter a value between 1 to 15 in the Number of Colors dialog box.
  11. In the Type area, select Flat Region.
    The threshold value is calculated based on the values specified for chord length and height.

    The surface is colored as follows:

    • The areas with curvedness value greater than the threshold value gets red color.
    • The areas with curvedness value less than the threshold value gets blue color.
  12. In the Type area, select Curvedness.
    The values in the color scale dialog box are updated automatically.

    The color scale value ranges from zero to maximum. Only positive values are allowed.

  13. In the Type area, select Shape Index.
    The range of color scale is from -1 to 1. The colors and values are fixed.

    The plane shape is colored pink but pink color is not available in the color scale dialog box.

  14. Click OK to create the analysis.

    The analysis is updated automatically whenever you modify any of the elements in the analysis (for example when you deform an element using control points.)

    Note: If a part body is selected for analysis the following behavior is observed:
    • The result is same as the result displayed if the last modified/created solid in the part body is selected.
    • Any changes made in the partbody are taken into account for analysis.
    • If the solid above the last updated solid is an in-work object, the analysis is not displayed.

    In the Options area, you can click Specialized Tessellation and then click Apply for better visualization. When you click the option again or click Cancel, the tessellation changes applied are reverted back to the previous settings.

  15. Optional: Right-click the Surfacic Curvature Analysis.x feature in the tree and select Surfacic Curvature Analysis.x object > Deactivate to deactivate the analysis and work on the surface feature.