How to Change Vertex IDs in Maya

You can change vertex IDs in Maya by using the Reorder Vertices command to change the order of vertices on your object.

Understanding Vertex IDs and Order

Vertex IDs in Maya are essentially numeric labels assigned to each vertex of a polygon object. These IDs are determined by the internal order in which the vertices are stored. While you can't directly assign a specific ID to a specific vertex, you can change the IDs by changing the vertex order. The Reorder Vertices command is the primary tool for this.

How to Reorder Vertices

Changing the vertex order, and thus changing the vertex IDs, involves a simple process using a dedicated Maya command.

Here are the steps:

1. Delete History: It's crucial to delete the history of the polygon object before attempting to reorder vertices. This helps prevent unexpected results or dependencies.

   • Select the object.
   • Go to Edit > Delete by Type > History.

2. (Optional) Display Current Vertex IDs: To see the current vertex IDs before and after reordering, you can display them in the viewport.

   • Select the object.
   • Go to Display > Polygons > Component IDs > Vertices. The IDs will appear next to each vertex.

3. Use the Reorder Vertices Command: This command allows you to interactively select vertices in the order you want them to be numbered.

   • Select the object.
   • Execute the Reorder Vertices command. You can typically find this in the Modeling Toolkit or search for it using the search bar (magnifying glass icon).
   • Follow the on-screen instructions or prompts in the command's options (if any) to select the vertices in your desired new order. The first vertex you select will become vertex ID 0, the second will be ID 1, and so on.

After completing the command, the internal order of the vertices is updated, and if you have component IDs displayed, you will see the vertex IDs have changed according to your new selection order.

Key Considerations

• Impact on Rigging/Animation: Changing vertex order and IDs can significantly impact rigging, skinning, and any animation setups that rely on specific vertex indices. Always exercise caution when reordering vertices on objects that are already part of a rig or animation pipeline.
• Topology Changes: The Reorder Vertices command changes the order, not the topology (the connections between vertices).
• Alternative Workflows: Sometimes, achieving a specific vertex order might be easier by exporting and re-importing the mesh in certain formats, or by using scripting, but the Reorder Vertices command is the standard interactive tool.

Changing vertex IDs in Maya is achieved by restructuring the internal order of vertices using the Reorder Vertices command, ensuring you manage object history beforehand.