Without saying, I can adjust Levels Viewport or Render to make my object looks more delicate. However what's the difference between these two options? And when and which do I adjust under what kind of circumstances?
1 Answer
Viewport is what you see in your 3D Viewport panel "live" on your computer in Blender. So whenever you change the level you will directly see it.
Normally, when you are "ready" with your work you will "render" your work (animations/pics). This you do by tapping F12 or CTRL-F12. Then Blender does the "good stuff", which means takes all into account it can like lights, samples, raycasting and so on and renders the result. For this "rendering" the subdivision render level is for.
You can keep these values equal as long as your models are low-poly and Blender reacts quickly on your actions. But if you have lot's of models with lots of vertices (like more than 1000k - depends on your computer capabilities) - every computer will become slower and slower and so Blender will be very slow and you will have no fun to work with it. Then you can lower the viewport render level and Blender will be much faster the lower this level is.