Problem with visibility limits enabled

[paulcroft]

Hi Pete

When I have visibility limits enabled (virtually all the time) I can see translucent white 'diamonds' being formed on the ground beneath me. They appear to be possibly the tiles of the underlying textures. These only extend for a defined area underneath where the aircraft is flying, not all the way to the horizon. The degree of transparency increases or decreases with the range I set, i.e. if I set vis limits to 60 miles on a clear day the tiles are more transparent than when the vis limit is set to 30 miles. These translucent diamonds are present whether or not there are any clouds in the sky. I use the FSW clouds. I have tested and the problem also exists with the default clouds.

I know FSUIPC is not the cause but I wondered if you or any of your readers might have come across this before and be able to guide me in the right direction.

Thanks in advance

[Pete Dowson]

When I have visibility limits enabled (virtually all the time) I can see translucent white 'diamonds' being formed on the ground beneath me. They appear to be possibly the tiles of the underlying textures. These only extend for a defined area underneath where the aircraft is flying, not all the way to the horizon. The degree of transparency increases or decreases with the range I set

You'd get the same without FSUIPC if you set a lower than a certain visibility in FS's weather. What happens is that Microsoft, in their wisdom, decided that when viewed from above the visibility layer, fog and mist layers below sohuld not looks completely transparent -- which they used to be in all previous versions of FS. this was after complaints about this from users ("why, when I climb out of thick fog and things clear, can I see the ground clearly below me?").

Their fix to this was to automatically add a thin layer of stratus cloud (unlisted in the clouds area) at the top of the visibility layer -- thicker for lower visibility, thinner for higher visibility. The problem is that this cloud layer obeys the rules you set for other clouds (in Options-Display-weather), and there is a limit to how far out those clouds are drawn, the same as for "real" clouds.

One answer which partially works is to use FSUIPC's graduated visibility facility. The only other way is to go into the FS weather menus and set the top of the visibility layer well above you. Unfortunately that would give you a fixed limit all the way up to that level.

Regards,

Pete

[paulcroft]

Hi Pete

Thanks so much for taking the time to explain what's going on. As it happens, in the meantime I've been experimenting with different video drivers and the latest nVidia WHQL set seem to have fixed it. I hadn't actually expected this to work because (a) I was certain that the problem preceded my last driver change, and (b) I rarely change video drivers since it's my experience they're usually 2 steps forward and 1 step back :).

Nonetheless it seems to be fixed now and I've learnt something more about how FS works into the bargain.

Thanks again for taking the time to explain and best regards

[Pete Dowson]

I've been experimenting with different video drivers and the latest nVidia WHQL set seem to have fixed it. I hadn't actually expected this to work ...

Ah, in that case it either wasn't the added top-of-layer stratus, or it was but the new drivers did a better job of smoothing them or making them suitably translucent. Nevertheless, if it is related to the visibility layer, which it seems it is by your reference to it only happening when setting limits, I would expect you still to be able to see the edge when at sufficient altitude.

Regards,

Pete

[paulcroft]

I would expect you still to be able to see the edge when at sufficient altitude.

How high should I go to see this Pete? I cannot see it at 10,000'. Not that I want to see it you understand ( :) ) but I'd rather like to find out if it really has gone now.

[Pete Dowson]

How high should I go to see this Pete?

The edge of the stratus layer marking the top of the low visibility layer? Well, high enough so that the horizon is further away than the cloud drawing distance set in Options-Settings-Display-Weather, of course.

If you are using FSUIPC's graduated visibility set so that you have, say, an upper visibility limit of 60 miles at altitude 25000' and the cloud drawing distance is 60 miles or less, then you should never see the edge. This is what I meant by that facility helping to partially fix, or rather hide, the problem.

I cannot see it at 10,000'. Not that I want to see it you understand ( :) ) but I'd rather like to find out if it really has gone now.

I don't think it can actually 'go' until Microsoft alter the code. It's just the way FS works.

If you are never seeing it then one of these things must be true:

1. Your visibility layer is not set with a low enough visibility to generate the stratus on top (try 10 miles or less)

2. The top of the visibility layer is above you (check the Weather dialogues)

3. You have some cloud texture set which effectively sets that particular cloud type at that sort of altitude transparent, thus effectively defeating the facility in the first place.

Maybe your original effect was bad rendering of textures in any case, hence fixed by the driver update. But in that case I fail to see how they were related to visibility limits.

Regards,

Pete