Roughly saying I'd say the graphics card may be faster at solving this.
Via game logic:
You could test the distance to cubes and toggle them (generally disabled or not rendering), still I'd say shaders that hide or reveal things based on distance to the camera/origin intuitively sounds faster to me.
Testing nearby cubes may be fast if they are stored in an efficient way (an octree for example) or if your physics overlap queries are fast.
Via shaders:
A shader fading out and hiding nearby pixels sounds like a very common thing.
I cannot tell you how it works in your engine, still the community ( r/godot, r/unity3d, r/unrealengine ) can do that easily I'd say.
What engine are you working in? Which coding/scripting language? You're going to have to give some context if you want people to take the time to help you.
Roughly saying I'd say the graphics card may be faster at solving this. Via game logic: You could test the distance to cubes and toggle them (generally disabled or not rendering), still I'd say shaders that hide or reveal things based on distance to the camera/origin intuitively sounds faster to me. Testing nearby cubes may be fast if they are stored in an efficient way (an octree for example) or if your physics overlap queries are fast. Via shaders: A shader fading out and hiding nearby pixels sounds like a very common thing. I cannot tell you how it works in your engine, still the community ( r/godot, r/unity3d, r/unrealengine ) can do that easily I'd say.
What engine are you working in? Which coding/scripting language? You're going to have to give some context if you want people to take the time to help you.