Lock Mesh Edges

Taking a look at preventing Edges from being optimized when using the Skeletal Mesh Reduction Tool.

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While the Skeletal Mesh Reduction tool does a great job at optimizing your project's Skeletal Meshes, there could be instances where it introduces visual errors as vertices are removed. For example, if your project requires that the head and body of your characters be separated, you could run into issues where head and body no longer line up correctly because the geometry has been altered too much. In the following how-to, we will take a look at how you can prevent this from happening by using the Lock Mesh Edges feature.


  1. Open up a Skeletal Mesh that has edges or vertices that are not connected to any other geometry in the Skeletal Mesh Editor.

  2. Next, make sure that the Skeletal Mesh has one or more LOD's generated for it.

  3. Expand one of the LOD's and under the Reduction Settings , enable the Lock Mesh Edges option by clicking on the checkmark box next to it.


  4. Once Lock Mesh Edges is enabled, press the Regenerate LOD button to remake the LOD's.

End Result

While the rest of the face is now simplified, the original vertices along the cut at the neck are retained, guaranteeing the head seamlessly fits to the original body.  Note that retaining detail at the mesh edge is not free - other parts of the face are simplified to attain the specified triangle budget for this LOD. In the image comparison below, you can see the effect turning on Lock Mesh Edges has a Skeletal mesh when it is enabled versus disabled.

Lock Mesh Edges Off

Lock Mesh Edges On

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