You have overlooked the necessary components of 3D rendering....that ball is not modelling the surface properties of the moon in any way. And the sun is not emitting enough light and if they apply directional light as opposed to point light....
It's complexity that has been overlooked...your model is broken and simple. No matter your intentions, this is a bad....bad...example.
Download Blender....spend 10 hours learning some basics...and come back ..
Sorry, but your model is fundamentally wrong.
You have overlooked the necessary components of 3D rendering....that ball is not modelling the surface properties of the moon in any way. And the sun is not emitting enough light and if they apply directional light as opposed to point light....
It's complexity that has been overlooked...your model is broken and simple. No matter your intentions, this is a bad....bad...example.
Download Blender....spend 10 hours learning some basics...and come back ..
Then clearly you can provide an image that gives us a crescent shaped lighting on a sphere.
https://www.google.com/search?q=shpere+rendering&tbm=isch
Take your time. Any image will do.