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Guest The_Sarge

Low fps with gmax objects even if...

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Hi all!I'm working on a complex scenery with thousand of High Voltage towers and telephone poles. First I used objects from FS2004 Library Objects, but the fps was too low. Now I use self gmax designed objects. I get better fps, but anyway there are too low. My objects are designed with gmax using LOD method. I also tested a sample object (a gmax cube) without LOD definitions tweaked by MDLTweaker using a low view distance. But the fps is always too low!!!I verified that the low fps are caused by the number of objects placed in the scenery, independently if they are visible or not. The best example is this: if I use 1000 gmax cubes with a very low visible distance, the fps are the same if I don't apply visible restrictions to these objects. W H Y ????????There is an alternative method to get better performances with gmax objects? There is another program to design objects with much better performances?Thanx, Aqui

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Hi Aqui.What you discovered is true. Visible or not, the number of polygons will be the greatest factor in reducing FPS. The objects, textures, and positions are all still in memory, and must be accounted for in the sim. Using different LODs may actually increase the memory load, as the total number of polygons would rise.I have not tested this, but it may be worth a try.Arno's website has the discussion and files to kill the shadow of objects... that will save some FPS. There is also a discussion of limiting the distance of objects... not LOD, but actual refpoint distance.Also, if the objects are made using colors, rather than textures, it may help.And, the crashbox could be removed from the objects, as well.Dick

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Hi Dick,thank you for the answer. About the refpoint distance, I have already tested it using MDLTweaker. But the fps is the same of a visible object.What is "crashbox" ?AQUI

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Hi Aqui.If you use MDLCommander to allow the options of MakeMDL, then you should be able to deselect Crash option. This stops the creation of the crashbox.Dick

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Hi Aqui,How did you place all those objects? Maybe that code can be optimized further as well.

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>Hi Aqui.>>If you use MDLCommander to allow the options of MakeMDL, then>you should be able to deselect Crash option. This stops the>creation of the crashbox.>>DickWhat is the crashbox?

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>Hi Aqui,>>How did you place all those objects? Maybe that code can be>optimized further as well.Hi Arno!I place the objects by a XML file like this:<?xml version="1.0" encoding="ISO-8859-1"?> ......

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The code that checks if your plane has hit your object and should thus crash.

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OK, so each object has it's own SceneryObject command. Not much you can do to optimize that further I guess.

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I think I will design telephone poles with two methods:1) For low performance PCs the Telephone poles will be custom houses with flat roof, 0.2 x 0.2 metres base and 7 metres height. I can place 595 poles per 25kmq2) For high end PCs the Telephone poles will be gmax objects.Thank you.RegardsAqui

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>Hi Aqui.>>If you use MDLCommander to allow the options of MakeMDL, then>you should be able to deselect Crash option. This stops the>creation of the crashbox.>>DickThe fps is too low also with crashbox disabled.

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Better yet make the "houses" three sided and reduce the polys even more.

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How can I create a three sided "house"? Pheraps with a MultiSidedBuilding with three buildingSides? In this case, if I enable smoothing, the fps goes down or not?ThanxAQUI

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Hi Arno,DickI also have this problem with my project. I don't think that the number of polygons is the cause because using a simple model or a more complex model has no effect.I have tried substituting all my models with a non textured simple plane (as low poly as you can get) and still the FPS plummits. My theory is that it is the sheer number of objects that FS must keep track of position that brings the FPS down.Do you think this can be cured by upgrading cpu/memory or is it more likely an FS9 issue that cannot be solved by throwing new hardware at it?I think that this is a very important problem to discuss and if possible solve.Vincent

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Hi Vincent,It's hard to say something about this. For example how many objects have you added (and how big is the area you have added them to)? And how big is the framerate difference caused by adding them?Adding extra detail will always have an influence on the performance. You can't expect your more detailed scenery to have the same framerates as the default scenery.Saying if extra hardware helps is always hard, as even with the same hardware users get different framerates in FS. It just depends on many different parameters.

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Hi ArnoI understand what you are saying but it was Dicks implication that the FPS is only dependant on Polygon numbers within scenery that I was questioning.If that were the case then throwing hardware at the problem would almost certainly do the trick.My own experiments lead me to believe that the amount of objects (however polygon friendly)has an equal if not greater importance to just the polygon numbers.When there are thousands just keeping track of the ref points must add an enourmous amount of cpu calculations. What I am wondering though is if there is another limitation within the program (not hardware or tweak configurable) that means full population with objects is just not possible within FS9?I'll send you some details of my project on your own site Arno and you'll see why this question is so important for me to answer.( perhaps I am attempting the impossible).warm regardsVincent

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Hi Vincent.The number of polygons is increased by the number of objects. And the texturing of those polys adds to the complexity.Could the problem be solved by quicker CPUs, wider pipelines and more/quicker memory? Yes... but such hardware does not yet exist.Where is the 10 Ghz CPU with access to 20Gb memory? It's in 2011.Dick

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Hi Dick:-) Perhaps I am misunderstanding something,I thought that polygon count is only relevent to the visable objects on screen and therefore mostly GPU dependant,using simplified models (as in my experiment )should by definition improve performance,it did not.All the objects that remain outside the field of view only their posistions kept track of,stored in memory and constantly checked ready to be called as soon as they come into view.Only then do the polygon numbers become relevant( I mean if we are using the same library object over and over again) Is this not correct.Vincent

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Hi Vincent,Yes that sounds correct. The only problem is that we no longer exactly know what the visible distance is. The scenery engine determines it automatically now, so maybe it is a lot bigger then we think?

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Hi againSo consider what would happen if we conducted this experiment....1:Create a simple gmax object such as a non textured box.2:Apply a distance check of say only 50 meters.3:compile into a library bgl.4: Place thousands of the object in the Sim by use of the autogen xml and annotator.What will be the resulting impact on FPS when you consider only the objects within a 50 meter radius are visible and adding polygons to the scene?I can tell you that FPS will plummit, even though the sim only has a small number of polygons to draw at any one time and the objects are all placed in the same.... I assume frame friendly manner that MS uses to fill the landscape with autogen.Under these circumstances what is responsible for the fall in frames?Is it solely the load on cpumemory cross checking position or is there another problemlimitation under the hood of the scenery engine itself?I am very interested to know your thoughts on whether real world object density is a possibility with todays hardware and todays flightsim.Vincent:-sun1

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I agree with you. Low fps affects all objects that aren't autogen trees or autogen buildings. In fact I have designed a big scenery with thousand and thousand of autogen trees and buildings, but the fps is very high! If I upgrade this scenery with some gmax objects the fps goes too low. RegardsAQUI

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Hi Vincent,I did a quick test. I made an array of 101x101 (10201) objects, placed something like 50 meters apart from each other. For the moment I used a very simple cube as test object.When I loaded this scenery with the cube right away from GMax the framerates indeed dropped very much when I had almost the entire array in view (I got around 4 frames in that case). When only part of the array was in view the frames were better (around 10 going up to 20 near the border of the array).The next test I did was add a distance check to the MDL object, causing it to only be displayed when you are at a distance of 500 meters or less of the cube. Reloading this scene I got around 17 frames all the time now). And of course less objects were drawn on the screen.So I think adding a distance check (or maybe also LOD, didn't test that yet) certainly helps in improving the performance. The fact that the frames were that low with all objects visible indicates that we should not try to reproduce the density of the real world yet :).

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Hi Arno!We can have a scenery with the real density only if we use autogen trees and buildings. The limit is this: 300 buildings per square kilometer, 600 trees per square km, 595 buildings self made (bglcomp objects) per 25 square km. Actually my scenery has about 50000 trees per 25 square km and 5400 building per square km.Aqui

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Are you using an LOD scheme to reduce the triange count when objects appear very small? This is a common issue. Unless you include lower poly-count LODs FlightSim will render all the geometry no matter how small the object appears on screen.

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