Autogen Tree Shadows - Strange rendering behavior.

[FlightSimDimm 16]

Hello All -

 

I have been witnessing a strange behavior on my Prepar3d 3.3.5 with the rendering of the autogen trees and their shadows. It has because even more pronounced since I started using the Prepar3D Tweak Assist (PTA) since it darkens up the shadows. I have already confirmed that it does the strange rendering using the standard shader files.(so PTA is not to blame)

 

I am a low and slow pilot, flying generally over the Pacific Northwest with my autogen trees maxed out. I recently turned on the autogen tree shadows and really liked the additional depth and realism that it added to the sim.

 

What I noticed now while flying around and above the treetop level, is the rendering or almost like painting of the shadows popping up on individual trees in front of me. It seems to be worse when I am flying into the sun and the shadow would be on the side of the tree I am flying toward. It reminded me of the old autogen popping up.

 

I spent 5 hours yesterday (my wife thinks I'm nuts) trying all sorts of shadow changes (shadow distance, shadow quality, cfg file settings), disabling SLI, dropping back to driver 361.43 (Rob's recommended driver), restoring the original shaders, etc. and still get the same behavior. 

 

Has anyone else seen this? Any recommendations on minimizing the effect or fixing?

 

Thanks,

Daniel

[AnkH 2,261]

Without any screenshot it is rather hard to get what your problem is all about. A guess: do you also have "receive" shadows for the autogen trees activated? Might be simply that? I also have all shadow options activated for my VFR flying and so far did not recognize any unusual behaviour, but probably I simply missed it...

[FlightSimDimm 16]

Without any screenshot it is rather hard to get what your problem is all about. A guess: do you also have "receive" shadows for the autogen trees activated? Might be simply that? I also have all shadow options activated for my VFR flying and so far did not recognize any unusual behaviour, but probably I simply missed it...

 

Hi - unfortunately a screenshot would not show it. Yes, I have the receive shadows ticked on. I noticed the behavior everywhere but was flying mostly in Orbx PNW, Cascade Locks Airport. I do have Orbx HD trees installed but cannot image that is the issue since all the trees in all the default scenery have the same strange shadow drawing. 

[TurboTomato 90]

I still get shimmering autogen shadows if I turn them on.

[Guest]

I ran a quick test with just base P3D 3.3.5 and FTX Global only ... no HD Trees, no PTA ... nVidia drivers 368.39.  Unfortunately I wasn't able to replicate your issue?

 

Can you provide a video that demonstrates the problem?

 

Cheers, Rob.

[FlightSimDimm 16]

 

 

Can you provide a video that demonstrates the problem?

 

Thanks Rob - I'll put together a video this evening.

[Novation 534]

I've not noticed anything like you describe, but that vid would help get a full handle on what you're seeing. I'm running Orbx HD Trees along with PTA and all shadow option ticked, except non flagged (or whatever it is) and all shadow sliders at mid point. The only thing I see that is less than ideal is some shimmer from the blocky nature of the shadows in the mid to far distance.

 

Standard tree autogen has a horizontal texture that pops up at close range, but Orbx HD trees do not have this texture, unless you have not ticked them in FTX Central, or the install went wrong, and you are still running default Autogen by mistake.

 

Nv driver version 368.69 btw.

[Guest]

The only other thing I can think of is clipmode ... are you running EZDok or some other product that adjusts cameras (Opus)?

 

Cheers, Rob.

[FlightSimDimm 16]

 

 

The only other thing I can think of is clipmode ... are you running EZDok?

 

No EZDok installed. My add-ons are only payware like Orbx, Opus, and UT2.

[FlightSimDimm 16]

Ok- here is the video. I run 3 screens and used ShadowPlay to make it. The end of the video has my setting. I have not changed anything from in the cfg file for the shadows.

 

Notice in the center of the screen, the shadows pop into view on the individual trees as I fly over the treetop level. If you cant run the video across three screens, then try running at half speed. You can clearly see the tree shadow behavior in this. Best played on an iPad and double click the screen to zoom in full screen.

 

https://drive.google.com/file/d/0B2D1Nes8ShkLLUVWczJUWGpGZzQ/view?usp=sharing

 

Thanks for looking at it... I'm baffled...

[AnkH 2,261]

Ok, now in the video it is clearly visible and this again let me think of the relevant option influencing this is: "receive shadows". Did you try with "receive shadows" for trees on off? It looks to me as this what you see here is the shadow of the tree casted on itself is displayed sometimes to late or later than the rest, that's why it looks popping. I am almost sure that it is the shadow casted from one of the tree sprites to the other (trees are basically two sprite textures combined in a 90° cross if looking exactly from above).

[Novation 534]

It seems to be a design limitation of the shadow system on autogen trees. There must be a hard coded distance limit that is not affected by the settings sliders. I've just done a similar tree top scraping flight in your video and see the same thing, and it is more noticeable depending on the position of the sun, as the shadows are in front of the object and you therefore see them being drawn. It might be possible to tweak the draw radius, but obviously performance would suffer badly.

 

BTW play any PC game and you will see very similar shadow drawing as you move. Shadows are very demanding to render, so there has to be a limit.

[JimmiG 244]

BTW play any PC game and you will see very similar shadow drawing as you move. Shadows are very demanding to render, so there has to be a limit.

 

It happens in X-Plane and Aerofly FS 2 which use a similar shadowing system. Pretty sure I've also seen it in GTA 5. Realtime rendered shadows work great in a confined space such as a first person shooter where the maximum distance is perhaps a few hundred meters at most. However it becomes problematic when you want to apply shadows to an entire outdoor scene with a draw distance of perhaps 50 miles.

 

Increasing the draw distance reduces the apparent resolution of the shadows, unless you also increase the resolution of the shadow maps (which impacts performance). Cascaded shadow maps help

 

However it's not enough for the extreme draw distance of flight sims.. So if they were to increase the tree shadow distance, the shadows would flicker and become pixelated instead. It's a tradeoff

[Guest]

It's a precision problem and no 64bit will not solve the problem.

 

I ran a quick test flight last night on my main sim PC and distance mapping precision was apparent (note Terrain shadow precision seems fine), but I was NOT seeing the issue Daniel presented?

 

 

Have you done any tweaks to adjust the shadow maps or shaders?  Mine are very subtle, your video they seem too dark to me.

 

Cheers, Rob.

 

NOTE: tree shadows are pretty hard on the GPU, I don't typically operate with them On.

[FlightSimDimm 16]

Hi Rob -

 

The prepar3d.cfg setting for the shadow entries have not been modified. I did use the PTA to darken the autogen shadows for the shaders and it is more pronounced now.  When I reverted back to the default shaders, it did the same thing, only less noticeable because they were lighter. I also have the receive shadows ticked for the autogen trees. I do not use any terrain shadows, just cloud shadows. I think my video has the setting at the end of it...

 

I am running 2 980GTX, SLI using 361.43. Behavior is there with or with SLI enabled.

 

Thanks.