Jeroen (J van E) found this nice tweak to make shadow draw distance the same at different shadow quality settings:

 

http://forum.avsim.net/topic/427529-simple-solution-for-shadows-and-loss-of-fps-or-the-tweaking-has-begun/

 

By default, the shadow distance settings in Prepar3d.cfg are like this:

   SHADOW_DRAW_DISTANCE_LOW=4000
   SHADOW_DRAW_DISTANCE_MID=6000
   SHADOW_DRAW_DISTANCE_HIGH=8000
   SHADOW_DRAW_DISTANCE_ULTRA=12000

 

And I decided to take one step further to do this:

   SHADOW_DRAW_DISTANCE_LOW=48000
   SHADOW_DRAW_DISTANCE_MID=24000
   SHADOW_DRAW_DISTANCE_HIGH=12000
   SHADOW_DRAW_DISTANCE_ULTRA=12000

 

Right, my shadow draw distance at Low setting is at 48000, 4x the distance of Ultra! So how does it work? Here are the screenshots.

 

1. Ultra@12000, even my mighty 780ti SC is literally brought to its knees, the fps is 18 and microstuttering is almost unbearable.

 

2. High@12000, instant gain of 12fps over Ultra, same shadow distance, and hardly any visual differences. Smooth.

 

3. Mid@24000: now the draw distance is doubled from High/Ultra (4x the default setting), you clearly see more shadows further away, yet fps goes up another 4fp, to 34fps.

 

4. Low@48000: this is 8x the default Low distance, and 4x the Ultra distance. You see shadows nearly as far as you can see. and the fps goes yet another 2 more to 36fps!

 

Now, here is the drawback as far as I could notice: Low and Mid settings are perfectly fine for mountains, but somehow they don't work well in cities. I got faint flickering shadows when there are lots of autogen buildings and trees etc. Set shadow quality to High cure this problem.

 

So overall this is a nice solution. Flying over mountains and canyons I'll just do Low@48000, while over cities I'll do High@1200. Until GTX980 coming out, I won't even think about Ultra.

 

By the way, I did some experiments and found shadows seem to completely GPU-bound. I found setting shadow to Ultra makes no difference in CPU usage, but makes 780ti go crazy...

Well thanks for that !

 

I hadn't gotten to testing terrain shadows yet but now I won't have to, as this is exactly what I wanted to test.

 

One question, at the higher distances, was there any flickering of shadows in the distance ?

Sorry for these big images.. my first time posting the images here..

I've been running Medium shadows with the draw distance at 12,000, but wasn't satisfied as I could still see the terrain shadows climbing up mountain sides closer to the plane that I would like.  I was planning to bump them out to 24,000 tonight and see what that does, so thanks for testing for me.  ^_^

@Brian: those terrain shadows are pretty solid. I think terrain shadows close the edge of drawing cone tend to flicker, so  long distances like 48000 push flickering shadows far away enough that they become almost unnoticeable.

@Brian: those terrain shadows are pretty solid. I think terrain shadows close the edge of drawing cone tend to flicker, so  long distances like 48000 push flickering shadows far away enough that they become almost unnoticeable.

 

Excellent.

 

I will certainly be trying your suggested settings for my next flight.