added prompt before KdTree generation to get at least some informatio…

src/PRo3D.Core/Surface/SurfaceApp.fs

@@ -1246,7 +1246,10 @@ module SurfaceApp =
                                 yield GuiEx.iconCheckBox s.isActive (ToggleActiveFlag key) 
                                 |> UI.wrapToolTip DataPosition.Bottom "Toggle IsActive"
 
-                                yield i [clazz "exclamation circle icon"; onClick (fun _ -> RebuildKdTrees key)] [] 
+                                yield 
+                                    i [ clazz "exclamation circle icon"; onEvent "generate" [] (fun _ -> RebuildKdTrees key)
+                                        // kdTreeRebuildOptions is in utilities.js
+                                        clientEvent "onclick" "top.aardvark.dialog.showMessageBox(null, kdTreeRebuildOptions).then((r) => { console.warn(r.response); if(r.response == 1) { aardvark.processEvent('__ID__', 'generate');} else { console.warn('user cancelled kdtree construction.'); } });" ] [] 
                                     |> UI.wrapToolTip DataPosition.Bottom "rebuild kdTree"           
 
                                 let! path = s.importPath

src/PRo3D.Viewer/PRo3D.Viewer.fsproj

@@ -72,6 +72,7 @@
     <Compile Include="QueriesRemoteApi.fs" />
     <Compile Include="RemoteApi.fs" />
     <Compile Include="Program.fs" />
+    <EmbeddedResource Include="resources\utilities.js" />
 
     <Content Include="resources\rotationcubeXYZ\back.png">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>

src/PRo3D.Viewer/Viewer/Viewer.fs

@@ -2030,6 +2030,7 @@ module ViewerApp =
             { kind = Script;      name = "errorReporting";  url = "./resources/errorReporting.js"  }
             { kind = Script;      name = "resize";  url = "./resources/ResizeSensor.js"  }
             { kind = Script;      name = "resizeElem";  url = "./resources/ElementQueries.js"  }
+            { kind = Script;      name = "utilities";  url = "./resources/utilities.js"  }
         ]
 
         let bodyAttributes : list<Attribute<ViewerAnimationAction>> = 

src/PRo3D.Viewer/resources/utilities.js

@@ -0,0 +1,8 @@
+const kdTreeRebuildOptions = {
+	type: 'question',
+	buttons: ['Cancel', 'Yes'],
+	defaultId: 0,
+	title: 'Rebuilding KdTrees',
+	message: 'Creating KdTrees may take some time.',
+	detail: 'For progress and feedback please look at the console output. After regeneration, reload restart PRo3D and reload the surface.'
+};