Mesh Cutout Unity

Mesh Cutout is a simple asset used to generate meshes/cutouts based on the distance to an object at runtime in a performant manner.

Supported in ALL graphics pipelines, since the tool modifies the mesh data directly.

Import

• Go to Package Manager
• Go to Add Package from Git URL
• Add 'https://github.com/smitdylan2001/com.devdunkstudio.meshcutout.git'
• Click Add

How To Use

• Make sure the meshes used for Mesh Cutout have ‘Read/Write Enabled’ on.

• Put ‘CutoutMesh.cs’ on an object with a MeshFilter component

• Change Cutout mode to desired mode

• Add Reference Object transform (can be left empty if manually calling CutoutMesh.UpdateCarvedMesh();)

• Configure the minimum and maximum distances

• Enable Generate on Start to generate the cutout immediately on start

• Enable Generate on Update to generate the cutout every frame

• Enable Generate on FixedUpdate to generate the cutout every FixedUpdate interval

• To manually trigger the meshing call CutoutMesh.UpdateCarvedMesh(); (required a ReferenceObject Transform if not filled in inspector)

Demo

• Simple cutout (enclosing)
• Simple cutout with hole (enclosing)
• Simple cutout with hole (touching)
• Complex mesh with cutout (touching)
• Complex mesh with cutout and hole (touching)
• Complex mesh with cutout and hole (enclosing)

Limitations

• Currently only 1 reference object is supported
• Code runs on main thread (could potentially be faster with job system/burst support)
• Read/Write Enabled has to be enabled resulting in more memory allocation
• Could Potentially use MeshData for more performance: https://docs.unity3d.com/2020.1/Documentation/ScriptReference/Mesh.MeshData.html

How to contribute

• All contributions for flexibility, performance and usability are welcome
• Follow code conventions from CutoutMesh.cs
• For changes in functionality (such as multiple reference objects), make a new script
• Potential contributions:
  • Performance optimization
  • multithread support (jobified for loop and/or 1 job per meshed object)
  • run in editor
  • cutout preview system
  • Multiple reference objects support
  • Update Mesh Collider

Special Credits:

Bunny83 on Unity Forums for writing most of the script: https://forum.unity.com/threads/loop-through-triangles-performance-issue.1280498