Prepar3D v4.5 terrain engine

Any issues, problems or troubleshooting topics related to the Prepar3D client application.
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Prepar3D v4.5 terrain engine

Postby delly » Thu Mar 14, 2019 6:22 pm

I wondered if anyone from LM could confirm whether the terrain/autogen engine has been modified in v4.5?

Although I have a very smoothly running powerful machine and sim, after a >1hr flight across europe (Orbx, Active Sky yes) both terrain & autogen no longer continue to load in.

I have tried reducing and locking to 30FPS and not really pushing the rig (it will hit 60-80FPS). Eventually it does improve but at a substantial cost of fidelity which the system can easily handle. 2080TI / i9-9900K.

When I descend into the featureless, terrainless nothingness I press the wonderful Refresh Scenery mapped key and 1 minute later I have scenery loaded again.. BUT here is bug 2.. it only loads for that single tile!

If I continue to fly on say another 10 miles the autogen is nolonger loading and the CPU (8 of them) are at 100%. As a programmer I am desperate to know if there is a debug mode I could run to analyse what the engine is doing, it shouldnt be doing anything. Out of interest I left the sim paused CPU at 100% and watched TV. 21 minutes later suddenly the next tiles all loaded in and the sim was back from the dead! 21 minutes of computation on 8X 5GHZ cores! That's an absolutely insane amount of load!

My guess (as per my other posts) is that it is methodically still loading all the tiles along the route of the aircrafts path, which if it hasn't been keeping up could be half way across the world!

I know I am being ambitious here but could someone from LM confirm if this is a known issue and whether there are plans to address now or in future releases.

If my hunch is correct it seems there are a few relatively simple fixes that could help:
  • When the user requests Refresh Scenery, kill all queued terrain loading requests.
  • Constantly kill all terrain requests for autogen/mesh/terrain in the queue that are a) behind the aircraft and more than x miles away b) more than 20 miles away
  • When a plane is > FL200 stop loading autogen / high res terrain textures / scenery
  • Only consider or prioritise loading terrain / autogen in the direction of AC travel or Viewport.
Sorry if I am completely missing all the technical details of the engine but its a big guessing game.

Finally, and pushing my luck further, I wondered if there is a way for me to apply to join the beta testing team for future versions? As a FS fan since '92 and a software developer of risk modelling systems with a high end rig + lots or scenery I might be able to provide useful feedback.


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Re: Prepar3D v4.5 terrain engine

Postby flydog7 » Fri Mar 15, 2019 3:02 am

Thank you for posting this. I agree wholeheartedly that this would be a great benefit. There’s no point in pre-loading terrain and scenery not within current proximity of the aircraft. I like your suggestion of an altitude test by which to simplify the terrain loading.

Let’s hope LM will give this serious consideration.

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Re: Prepar3D v4.5 terrain engine

Postby fahdriyami » Tue Mar 19, 2019 1:14 pm

I think the autogen engine needs to be completely reworked anyways. Autogen in P3D is a mess compared to X-Plane, where there is a grid system. I hope it gets the rework it deserves, along with ATC.
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Re: Prepar3D v4.5 terrain engine

Postby sw34669 » Fri Mar 22, 2019 4:41 pm

+150 !
thanks for taking the time to suggest some possible easy wins. I hope we see something in 4.5 but it may be 5 for a new engine more, fit for purpose would be unfair, maybe, more aligned to the high res scenery and complex aircraft we use these days.

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Re: Prepar3D v4.5 terrain engine

Postby delly » Wed Mar 27, 2019 1:31 pm

more aligned to the high res scenery and complex aircraft we use these days.
I totally agree, the terrain pipeline was never really designed for the level of detail these new products are pumping out. The move to 64bit has opened the door to pushing evermore detail and the terrain engine isn't quite up to the task.

I do think the easy wins like the ones I mentioned above could be released in 4.5 and then a bigger rethink looked at in 5, potentially breaking backward compatibility in some areas.

All LM need to do is build a high end PC and ask ORBX to give them an install of all their scenery. I am pretty sure within a few days of testing they would find the problem areas.

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Re: Prepar3D v4.5 terrain engine

Postby sho69607 » Mon May 06, 2019 12:09 am

Sorry for the late reply on this topic, but I wonder if there are plans to overhaul the scenery completely in the future. LM has done a great job updating and adding features that Microsoft left off with when they terminated the flight sim program in 2009, but at it's core there are a lot of things that still resemble FSX. I'm sure it is a monumental task, but it would be nice to see a new autogen system, rather than updating scenery that was designed over a decade ago. Perhaps P3D V5? Only time will tell.

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