Why static lights create real-time shadows from static object to other static object?

I'm wondering. If a mixed light and 2 object are all static, the produced shadow will be calculated in real time, while it could be baked.

Static means the object transform won't change. In the specific case of light emitters, it should also mean that the light range won't change. So it would be logic to bake such shadows, allowing the author to gain some perfs wherever he can.

I understand that shadows may be affected by light intensity or color, and "static" only fixes the transform. But the author could simply make such lights dynamic.

So why these shadows are calculated in real time?

 

If you want to bake the shadows, switch the light from mixed to baked? I'm not seeing the issue here.

 

A baked light won't produce any shadow from and to dynamic object. The principle of the mixed light, as far as I understand, is to bake a maximum of thing, and compute what can't be baked in realtime.

 

Cool, but to have lights produce shadow from and to dynamic object, you need to calculate shadows in real time. Try Shadowmask see if you like it better?

It is possible to have unity not update any shadow maps if there aren't any dynamic objects in the light's furstum, some store assets do it, not sure if Unity does it native yet (maybe LWRP/HDRP?).

 

My point is that in distance shadowmask mode, Unity could make the economy of calculating shadows in real time for static lights and objects, as static means they won't change. The baked shadow would be enough.

The only drawback I see is that backed and realtime shadows may be visualy differnet, depending on the quality you set for each. But it's already a problem in distance shadowmask, at shadow distance, the blending is often visible.

 

Yes, such logic would be needed, but I feel like it would be much effective than casting real time shadows that will never move, considering the number of static lights used in the average scene.

But I understand it's not a trivial thing to implement. I was just wondering why the static status of lights was not used at all in shadowing as it is used in UnrealEngine. I understand that the real time lighting will be changed soon due to the deprecation of Enlighten. Maybe this point could be considered in the future system.

@uy3d, @AcidArrow, thanks for your answers !