Orbital height and impact on surface rendering

[lajoswinkler]

For Kerbin, it's 160 km. If you go below, surface features start to render, dropping the framerate considerably on non-beefy computers. That's why it's good to place larger orbital stations above that height.

What about other bodies? Also, are there only two modes for surface rendering? On and off, or more? If more, let's use the minimal height for total lack of surface rendering.

Gather the data and I'll put it here.

Kerbol

Moho

Eve 130 km

Gilly

Kerbin 160 km

Mun

Minmus

Duna

Ike

Dres

Jool

Laythe 160 km

Vall

Tylo

Bop

Pol

Eeloo

Edited January 4, 2015 by lajoswinkler

[lajoswinkler]

Nobody?

I think it's 130 km for Eve.

[Lunaran]

I've noticed this too.

What makes rendering so slow at certain altitudes is that it doesn't just cut off, it crossfades by altitude. This is a workable solution if you're passing through the crossfade zone quickly, but if you're in a circular orbit right in the middle of it your machine is always drawing both the planetary terrain quads and the scaled-space dummy planet, alpha blended together, which is worse than just drawing one or the other.

I've started launching to only 75km and putting stations at 250km just to stay out of that zone, because it turns my laptop into a hibachi. 100-200km is for RemoteTech satellites I'll never have to switch back to.

[lajoswinkler]

There might be steps, yeah, but there's an abrupt change at 160 km for Kerbin. Below that we might have steps. I'm interested in zero rendering which maximizes the station part count I can use.

[Highlad]

Perhaps its something to do with water rendering? I know there was the whole water lag thing a few versions ago.

[lajoswinkler]

Laythe changes the rendering mode at 160 km so I've added that into the list.

[problemecium]

Oh cool. I had always thought it was 300km or something ridiculous for Kerbin. If it's really only 160 then I guess it's time to move my station before I start adding a bunch of junk to it.

Thanx~!

[HarvesteR]

The scaled-space version of a planet (aka, the far-away version of it) is always rendered. In fact, the atmosphere is only present in scaled space, so even at the surface, the scaled-space version is active. Being just a static mesh, it's got minimal overhead to it.

The noticeable increase in performance is indeed very likely the PQS (Procedural Quadtree Sphere) surface being turned off after completely fading out of view. The crossfading is quite necessary for the transition to not look terrible, but once fully faded out, the terrain turns itself off and stops updating. This definitely would help increase performance quite a bit, especially if you're already running on the low end of framerate, so good tip there. If you plan to build big, build it at a high(er) orbit.

Cheers

[LethalDose]

The scaled-space version of a planet (aka, the far-away version of it) is always rendered. In fact, the atmosphere is only present in scaled space, so even at the surface, the scaled-space version is active. Being just a static mesh, it's got minimal overhead to it.

The noticeable increase in performance is indeed very likely the PQS (Procedural Quadtree Sphere) surface being turned off after completely fading out of view. The crossfading is quite necessary for the transition to not look terrible, but once fully faded out, the terrain turns itself off and stops updating. This definitely would help increase performance quite a bit, especially if you're already running on the low end of framerate, so good tip there. If you plan to build big, build it at a high(er) orbit.

Cheers

Cool. Any idea at what altitude(s) the "noticeable increase in performance" starts?

[SkyRex94]

are these distances hard-coded values? So if i'm playing with 3.2x RSS or 5xRSS is the height where PQS stops still 160km for Kerbin?

[Magion]

PQS fading is probably controlled by class ScaledSpaceFader, whose fields are public, so anyone can change them. But when dumped these values I got strange results - for Kerbin fadeStart=55000 and fadeEnd=60000. You report, that the lag stops at cca. 160km, so that's weird.

I also found PQSMod_CelestialBodyTransform, which has similar fields with more sensible values. fadeStart=60000, fadeEnd=120000.

So here're all the values from ScaledSpaceFader class:

[table=width: 330, class: grid, align: left]

[tr]

[td]CelestialBody[/td]

[td]fadeStart[/td]

[td]fadeEnd[/td]

[/tr]

[tr]

[td]Kerbol[/td]

[td]N/A[/td]

[td]N/A[/td]

[/tr]

[tr]

[td]Moho[/td]

[td]95000[/td]

[td]100000[/td]

[/tr]

[tr]

[td]Eve[/td]

[td]105000[/td]

[td]110000[/td]

[/tr]

[tr]

[td]Gilly[/td]

[td]135000[/td]

[td]140000[/td]

[/tr]

[tr]

[td]Kerbin[/td]

[td]55000[/td]

[td]60000[/td]

[/tr]

[tr]

[td]Mun[/td]

[td]55000[/td]

[td]60000[/td]

[/tr]

[tr]

[td]Minmus[/td]

[td]135000[/td]

[td]140000[/td]

[/tr]

[tr]

[td]Duna[/td]

[td]95000[/td]

[td]97000[/td]

[/tr]

[tr]

[td]Ike[/td]

[td]135000[/td]

[td]140000[/td]

[/tr]

[tr]

[td]Dres[/td]

[td]95000[/td]

[td]100000[/td]

[/tr]

[tr]

[td]Jool (why not null??)[/td]

[td]29000[/td]

[td]30000[/td]

[/tr]

[tr]

[td]Laythe[/td]

[td]55000[/td]

[td]60000[/td]

[/tr]

[tr]

[td]Vall[/td]

[td]295000[/td]

[td]300000[/td]

[/tr]

[tr]

[td]Tylo[/td]

[td]95000[/td]

[td]100000[/td]

[/tr]

[tr]

[td]Bop[/td]

[td]135000[/td]

[td]140000[/td]

[/tr]

[tr]

[td]Pol[/td]

[td]130000[/td]

[td]135000[/td]

[/tr]

[tr]

[td]Eeloo[/td]

[td]95000[/td]

[td]100000[/td]

[/tr]

[/table]

Values from PQSMod_CelestialBodyTransform:

[table=width: 330, class: grid, align: left]

[tr]

[td]CelestialBody[/td]

[td]fadeStart[/td]

[td]fadeEnd[/td]

[/tr]

[tr]

[td]Kerbol[/td]

[td]N/A[/td]

[td]N/A[/td]

[/tr]

[tr]

[td]Moho[/td]

[td]100000[/td]

[td]110000[/td]

[/tr]

[tr]

[td]Eve[/td]

[td]110000[/td]

[td]115000[/td]

[/tr]

[tr]

[td]Gilly[/td]

[td]140000[/td]

[td]145000[/td]

[/tr]

[tr]

[td]Kerbin[/td]

[td]60000[/td]

[td]120000[/td]

[/tr]

[tr]

[td]Mun[/td]

[td]60000[/td]

[td]120000[/td]

[/tr]

[tr]

[td]Minmus[/td]

[td]140000[/td]

[td]145000[/td]

[/tr]

[tr]

[td]Duna[/td]

[td]100000[/td]

[td]110000[/td]

[/tr]

[tr]

[td]Ike[/td]

[td]140000[/td]

[td]145000[/td]

[/tr]

[tr]

[td]Dres[/td]

[td]100000[/td]

[td]110000[/td]

[/tr]

[tr]

[td]Jool[/td]

[td]N/A[/td]

[td]N/A[/td]

[/tr]

[tr]

[td]Laythe[/td]

[td]60000[/td]

[td]120000[/td]

[/tr]

[tr]

[td]Vall[/td]

[td]300000[/td]

[td]325000[/td]

[/tr]

[tr]

[td]Tylo[/td]

[td]100000[/td]

[td]125000[/td]

[/tr]

[tr]

[td]Bop[/td]

[td]140000[/td]

[td]145000[/td]

[/tr]

[tr]

[td]Pol[/td]

[td]135000[/td]

[td]140000[/td]

[/tr]

[tr]

[td]Eeloo[/td]

[td]100000[/td]

[td]110000[/td]

[/tr]

[/table]

You can try and figure out which one is the correct one.