Simplify

Source file: simplify-a-surface.htm

The surface simplification tools reduce surface facet counts, while retaining overall shape. They will work on a selection of facets that can be an entire surface, a group of surfaces, or a selection of facet primitives on a surface. Surfaces may require simplification so they can be exported to software that is unable to handle large file sizes.

The simplification process will amalgamate the triangles in flat regions first, preserving edges and other curved areas. It will also simplify triangles around the boundary of the triangle selection.

You can simplify a surface by either facet count or by distance error. Each is described below. Click for detail.

Note:  Simplify by Facet Count should only be used if there is a specific number of triangles to which the surface must be restricted. This tool does not provide a method of limiting the surface deviation caused by triangle simplification. Simplify by Distance Error is the preferred method.

  1. Select the surface in the project explorer.

  2. On the Edit ribbon tab, go to the Surface group. From the Simplify drop-down list select Simplify by Facet Count.

  3. Set the Target facet count either by the slider or entering the desired number of facets the simplified surface will contain.

    The slider can be adjusted from one to the total number of triangles in the selection. If the slider is set to halfway, it will reduce the facet count by half. This can be applied repeatedly to further reduce the facet count by half each time this function is applied.

  1. Select Preserve surface boundaries to leave the boundary unchanged.

  2. Select Prevent self intersection to disallow line intersections.

    Note:  The simplification process will be slower when using this option.

  1. Click OK or Apply.

Tip:  You can quickly reduce a surface's facet count to 25% of the original. Right-click the surface and, from the context menu, hover over Edit and select Simplify facets to 25%.

Note:  Use this tool to limit the surface deviation caused by triangle simplification.

  1. Select the surface in the project explorer.

  2. On the Edit ribbon tab, go to the Surface group. From the Simplify drop-down list select Simplify by Distance Error.


  3. Enter the maximum allowable Average error by which the simplified surface can deviate from the original surface.

    4. Note:  The average error is the average distance from the original surface. Thus there will be some areas of the new surface that are further away from the original surface than the average error.

  4. Choose the required simplification options:

    • Select Preserve surface boundaries to leave the boundary unchanged.

    • Select Prevent self intersections to disallow line intersections.

      Note:   This will significantly slow the simplification down. Clear this option for a faster result.

  5. Click OK or Apply.

Note:  Simplification can introduce inconsistencies in the surface, such as triangles that overlap or cross. Click and follow the steps below to check for and fix inconsistencies.

  1. On the Query ribbon tab, go to the Surface group and select Surface Validity.

  2. Clear Check for surface closure as this option is only used for closed solids.

  3. Select Mark location of failures to create objects in the cad container that highlight the failure locations.

  4. Click OK.

  5. Drag the objects created in the cad container onto the surface view window to display any errors found.

  6. To repair a failure, zoom in to it and select the wireframe   surface render mode.

    Example of a failure

  7. Using Select points mode, select a corner point on the failure triangle and press Delete.

  8. Fill the resultant hole. On the Edit ribbon tab, go to the Fix group and select Fill Holes.

  9. Repeat steps 6-8 for all remaining errors.