   {
     for (auto & figure: this->figures)
     {
       if (!this->subframes[figure->framepos].hidden)
       {
         auto &renderer=this->subframes[figure->framepos].renderer;
         
         if (
           figure->IsEmpty()  
           || renderer->GetActors()->GetNumberOfItems()==0
           )
         {
           figure->RTBuildAllVTKPipelines(renderer);
           
           for (auto & actor: figure->actors) 
             renderer->AddActor(actor);
           
           for (auto & actor: figure->ctxactors) 
             renderer->AddActor(actor);
 
           for (auto & actor: figure->actors2d) 
             renderer->AddActor(actor);
           
         }
         
         figure->RTPreRender();
         figure->RTUpdateActors();
       
         renderer->SetBackground(figure->bgcolor[0],
                                 figure->bgcolor[1],
                                 figure->bgcolor[2]);
         
       }
     }
   }