Simple script for displaying mesh info for selection(s) containing MeshFilters / SkinnedMeshRenderers in Unity Editor

MeshInfo.cs

using UnityEngine;
using UnityEditor;

public class MeshInfo : EditorWindow {
  private int vertexCount;
  private int submeshCount;
  private int totalTriangleCount;
  private int triangleCount;
  private int uvChannels;
  private int blendShapesCount;

  [MenuItem ("Tools/Mesh Info")]
  static void Init () {
    // Get existing open window or if none, make a new one:
    MeshInfo window = (MeshInfo) EditorWindow.GetWindow (typeof (MeshInfo));
    window.titleContent.text = "Mesh Info";
  }

  void OnEnable() {
    Selection.selectionChanged += OnSelectionChange;
  }

  void OnDisable() {
    Selection.selectionChanged -= OnSelectionChange;
  }

  void OnSelectionChange() {
    Repaint();
  }

  int CountTrisInScene() {
    int totalTris = 0;
    MeshFilter[] meshFilters = Resources.FindObjectsOfTypeAll<MeshFilter>();
    SkinnedMeshRenderer[] skinnedMeshRenderers = Resources.FindObjectsOfTypeAll<SkinnedMeshRenderer>();

    foreach (MeshFilter mf in meshFilters) {
      if (mf.sharedMesh != null) {
        totalTris += mf.sharedMesh.triangles.Length / 3;
      }
    }
    foreach (SkinnedMeshRenderer smr in skinnedMeshRenderers) {
      if (smr.sharedMesh != null) {
        totalTris += smr.sharedMesh.triangles.Length / 3;
      }
    }

    return totalTris;
  }

  void OnGUI() {
    vertexCount = 0;
    triangleCount = 0;
    totalTriangleCount = CountTrisInScene();
    submeshCount = 0;
    uvChannels = 0;
    blendShapesCount = 0;

    foreach (GameObject g in Selection.gameObjects) {
      Mesh sharedMesh = null;

      // We want to check both MeshFilters and SkinnedMeshRenderers
      MeshFilter meshFilter = g.GetComponent<MeshFilter>();
      SkinnedMeshRenderer skinnedMeshRenderer = g.GetComponent<SkinnedMeshRenderer>();

      if (meshFilter != null && meshFilter.sharedMesh != null) {
        sharedMesh = meshFilter.sharedMesh;
      } else if (skinnedMeshRenderer != null && skinnedMeshRenderer.sharedMesh != null) {
        sharedMesh = skinnedMeshRenderer.sharedMesh;
      }

      if (sharedMesh != null) {
        vertexCount += sharedMesh.vertexCount;
        triangleCount += sharedMesh.triangles.Length / 3;
        submeshCount += sharedMesh.subMeshCount;
        uvChannels = sharedMesh.uv.Length > 0 ? 1 : 0;
        blendShapesCount += sharedMesh.blendShapeCount;
      }
    }

    EditorGUILayout.LabelField("Vertices: ", vertexCount.ToString());
    EditorGUILayout.LabelField("Polygons: ", triangleCount.ToString() + " (" + totalTriangleCount.ToString() + " in scene)");
    EditorGUILayout.LabelField("SubMeshes: ", submeshCount.ToString());
    EditorGUILayout.LabelField("UV Channels: ", uvChannels.ToString());
    EditorGUILayout.LabelField("Blend Shapes: ", blendShapesCount.ToString());
  }
}