Welcome to Cockpitbuilders.com. Please login or sign up.

February 25, 2021, 09:05:05 PM

Login with username, password and session length


Fly Elise-ng
28 Guests, 0 Users
  • Total Posts: 56753
  • Total Topics: 7556
  • Online Today: 30
  • Online Ever: 582
  • (January 22, 2020, 08:44:01 AM)
Users Online
Users: 0
Guests: 28
Total: 28



Will Depart in...



Prepar3d v5.1 has at least one good thing for cockpit builders!

Started by Neil Hewitt, October 31, 2020, 11:02:59 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Neil Hewitt

Hi all.

You'll have seen that P3Dv5.1 is getting slated over at the other site and on the LM forums because many of the EA problems have not been resolved. It appears that these problems are actually endemic to the TrueSky platform and that basically current graphics cards are not powerful enough (yes, really) to properly render volumetric clouds for a sim, and hence the workarounds are causing the grid patterns and object fringing that people are so annoyed about with EA, and that they simply may not be fixable.

It also seems that 3rd parties need to update their scenery to fix some of the problems with objects bleeding through cloud / haze / fog (basically, any volumetric weather object) which are down to coding using deprecated features (I stress I don't know this to be 100% true, that's just what I've read at the LM forums from their rendering engine lead) and of course the usual suspects (ORBX) have said they don't think it should be down to them to fix this. And with the current market so heavily focussed on MSFS, I doubt there'll be much fixing of scenery going on for a release that many people have said they will be skipping to stay on P3D 4.5.

There is some good news for cockpit-builders and those with multi-display systems, though. LM has, at long last, implemented simultaneous multi-projection (or as they're calling it, one-pass rendering) for ViewGroups. So if you have multiple views generated on a single PC using a ViewGroup, they are being calculated just once and then rendered to each view, instead of the scene being built and rendered separately for each view. For me, in some early testing, this has dramatically increased my FPS for a two-view system (from 22 FPS to 48 FPS at FlyTampa EHAM with most settings right). I haven't done any proper number-crunching but it seems like the penalty for extra view windows is significantly reduced.

This only works for ViewGroups, because they are guaranteed to consist of the same view type and are viewing the same scene. This does mean that it only works when each view is on a different display and would not work with multiple views butted together on a single spanned display [EyeFinity/Surround/TH2GO etc]. In my case, each view is on a separate projector and I don't have them spanned because I use Fly-Elise NG Immersive Display Pro + Calibration Pro to generate a 180-degree view on a curved screen.

I'm going to do some experimenting with higher numbers of views and look at the FPS differences and see if I can work out what the average % FPS loss is per extra window now. This could be a really big deal for cockpit builders, I think...


Following with interest. I am one of those still on P3D4.5.
FSX-SE,P3D4,W10-I7@4.8,W7-i7 920 ,W10-Dual Core@2.66.,FSUIPC 4 + 5,WideFS.Prosim737,JSV2,ASN, ,Vpilot,GSX,Pro-ATC/X,RAAS Pro,UT2,PFPX,TopCat,Accu-Feel




Still on P3D V4.5 here as well with a multi-channel setup, but that single-pass implementation is an interesting story to follow.

Fred K
Boeing 737NG-800, Prepar3D v4.5, Sim-Avionics 1.964, SimSync multi-channel (curved screen), Optoma 1080GTDarbee projectors (3), Fly Elise warping, FSGRW weather, FDS OH panels and CDUs, SimParts MIP, FDS SysBoards (OH), CPFlight MCPPro and pedestal panels, FI Gauges, PFC controls, converted motorized TQ (SIOC), Weber seats


I'm still using P4D v4.5x   If it ain't broke, don't fix it!

Version 5x still has some issues...

P3d v4.5x with Sim-Avionics (two computers), FDS MIP, 3-Optoma HD GT1080HD projection 120 deg. display driven by a single EVGA Nvidia GTX-1080Ti Water Cooled.  6dof Motion Platform using BFF 6dof motion software, driven by a Thanos Servo Controller to 6.2 KW Servos.

Neil Hewitt

Yes, I know lots of people have put off migrating to v5 at all given its chequered history. To be honest I'm not all that bothered by the EA stuff - I have it turned off - although of course it's nice eye-candy, but complex scenery, complex aircraft and complex EA weather simply don't mix. With EA on and clouds on Ultra I see a 15FPS loss straight out of the box, and with really heavy weather themes you lose even more. That's half my FPS on the ground at EGLC, which I can't afford to lose. So no EA for me yet.

I'm making a video for my YouTube channel about P3D v5.1 performance. I've been playing about with all the usual suspects in terms of settings and what I can say now is this:

  • 5.1 definitely improves performance out of the gate. I'm seeing general performance uplift of about 5-10 FPS for the same settings in the same location and aircraft.
  • Shadows and reflections can be pushed further right for the same FPS, but not all the way to the right, at least not in my system in complex scenery.
  • V5 generally has significantly lowered the hit from scenery and autogen complexity (which is the key reason I upgraded; it's also just *smoother* in a way I can't really explain), and 5.1 has improved this again. You can go sliders right on both and see very little performance impact. I was never able to fly in London in True Earth GB above Sparse scenery in 4.5 without dropping into the low teens. Now I can fly on Extremely Dense. It makes a huge difference. Draw distance does still cause a dip, but again not by that much, seems like about 5-10FPS hit max.
  • The performance hit for extra windows is also reduced out of the box, but only a little. Not really enough to notice if you're on low FPS already.
  • The single-pass rendering definitely improves things. Not as much as I'd hoped, but maybe enough to let me run a 3-view system on the one PC. At UK2000 EGLC / ORBX True Earth GB South, on max scenery complexity, I got a performance boost of 20% (which equates to +5 FPS in this setup) when I turned it on for my ViewGroup. Obviously in less complex scenery and less complex aircraft you should see a higher absolute FPS improvement. I shall do some similar tests at FlyTampa EHAM which is my other frame-rate hog airport at the moment.
  • It certainly hasn't done away with the performance penalty for multiple views altogether. But in my setup I can now get almost the same performance on my two-view image generator PC as I can on my host PC (albeit with a tweaked aircraft), and that's a significant improvement for me.
  • Everyone's mileage will clearly vary, but IMHO it's definitely worth playing with if/when you upgrade to 5.1


Does Active Sky work with V5.1 or still not fixed. Thanks for the review.
FSX-SE,P3D4,W10-I7@4.8,W7-i7 920 ,W10-Dual Core@2.66.,FSUIPC 4 + 5,WideFS.Prosim737,JSV2,ASN, ,Vpilot,GSX,Pro-ATC/X,RAAS Pro,UT2,PFPX,TopCat,Accu-Feel

Neil Hewitt

Hifi has just put out a Release Candidate of ASP3D that works with 5.1


FSX-SE,P3D4,W10-I7@4.8,W7-i7 920 ,W10-Dual Core@2.66.,FSUIPC 4 + 5,WideFS.Prosim737,JSV2,ASN, ,Vpilot,GSX,Pro-ATC/X,RAAS Pro,UT2,PFPX,TopCat,Accu-Feel

Like the Website ?
Support Cockpitbuilders.com and Click Below to Donate