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  1. #1
    Join Date
    Jul 2010
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    63

    Ability to load models like we load terrain?

    Just saw the latest video and it looks great. My only question is say I have a 3D model that is 400MB and when I convert that to FBX it becomes something like 1.5Gb (I have a few files like this at my job) ... Currently Unity cannot and will not load that model. Would it be possible that this system you are building could load a model like that? I guess what I am asking is does the terrain in the video load so fast because of how the terrain is constructed or does it load so fast because of how the 3D model of the terrain is handled?

    I think this is an important question in that if I wanted a very large complex city in this MMO and a ship were to be chugging along at 100 MPH, when it comes to something like a large city it would get crazy lag if those 3D models didn’t load as efficiently as the terrain. Right?

  2. #2
    Join Date
    Dec 2002
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    Virginia Beach, VA
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    861
    You will not be able to load a mesh of that size into Unity period with or without the techniques we will be showing since the most vertices you can load per model is 65k. Even if you were to break the model into many smaller meshes and load them individually at 1.5gb you are pushing up right against the most memory Unity can use since it is still only a 32 bit application.

    In a situation where we are flying near a city or other complex area with a lot of geometry we will be using low resolution geometry that won't be any where near the sizes that you are talking about. An entire city would probably be less than 100k triangles and probably even lower depending on the speed and altitude of the player that is passing by it.
    “little expense has been spared to give the impression that no expense has been spared.” - Douglas Adams

  3. #3
    Join Date
    Jul 2010
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    63
    so will there be hard restrictions to flight speed based on altitude then? Or some correlation between flight speed, altitude, and geometry LOD? Seems to me that if you are flying 200MPH at 5 foot off the ground meshes would load at full resolution and cause lag or collision issues. So if I am flying 5 feet off the ground my speed should be capped at 50MPH, at 1000 feet cap at 100MHP and at 2000 feet no cap ... just a thought, the numbers dont really matter as much as the concept.

    Another thought. what about the ability to crash your ship? I mean if you are flying at 200MPH and hit a building you should fall out dead and your ship should be in ruins to the point you basically have to re-build it.

    While I am talking I might as well throw out another Idea I had while watching that video. The concept of engaging stages of an engine like gears on a car. So Stage1=max speed 40MPH (for landing and idle flight), Stage2=100MPH, Stage3=150, Stage4=200, you get the idea.That way players can control the throttle a bit more. So that while i am trying to land if my cat jumps on my keyboard I dont go flying 200MPH into a building and die and possibly loose that cool ship I just spent 3 weeks getting.

  4. #4
    Join Date
    Dec 2002
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    Virginia Beach, VA
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    861
    The thing to remember here is that we aren't making a flight simulator but an MMO. So flight is a secondary concern and is being included as a means of transportation from point A to point B. Odds are that you will find that rapid transit such as shuttles, ferries, or whatever they end up being called will be the only ships that will get up to the faster speeds and that they will be on fixed paths to prevent them from skimming the ground at hundreds of mph. Player controlled ships will be more restricted in the speeds that they will be allowed to travel at and what types of vehicles can be used in what areas. For instance I have no intention what-so-ever to allow a player to fly a fighter plane through a city but I have no problem with allowing a motorcycle or a hover car. There will be a lot of R&D most likely to determine what works and what doesn't and then we would implement accordingly.
    “little expense has been spared to give the impression that no expense has been spared.” - Douglas Adams

  5. #5
    Join Date
    Jun 2010
    Location
    Kitchener, Ontario, Canada
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    258
    Key to remember is this is R&D, they were showing the patches being loaded as you approached and what the current R&D was able to do, dont get all tangled up in ideas about flying and speeds and all that other jazz. I loved how fast your able to load new patches as you were flying along, I think the capabilities so far exceed what most of us would use in a normal game.

    Im curious and maybe this is something your planning for a later R&D demo, but what happens when you start placing a lot of objects on those patches your loading..will the demo suddenly grind to a halt if for example you've modeled out a city that fills 2 or 3 of those patches..or will you handle that by going to a lower resolution rendering like discussed in the video to handle that sort of thing??

  6. #6
    Join Date
    Jun 2008
    Posts
    1,088
    I am quite excited about the new videos Lee! Thanks so much for busting your butt on this and bringing us this new system. I am curious how loading in geometry will affect the load times but it looks very promising. Are you planning on having the artist (Zak :P) create LODs or were you thinking of building a logarithm to handle it for you? I recently seen this http://forum.unity3d.com/threads/881...-Detail-system which I was tempted to pick up but wanted to wait and see how you were going to go about this issue.

    -Dane
    You know you want to!

  7. #7
    Join Date
    Dec 2002
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    Virginia Beach, VA
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    861
    I'm currently thinking that the objects that will decorates the terrain will use a combination of draw distance culling, frustum culling, and LoD depending on what type of asset it is. For instance grass, weeds, flowers, won't be visible beyond a fairly short distance say maybe a 100m while hero objects may be visible at 1km or more but will use LoD to reduce the load for those particular objects. Tress will probably use a combination of various techniques since they will need a system so that they look good from both the ground and in the air. It would look some what odd if soddenly all the trees disappeared the moment you got above a certain altitude. I still think that filling the world with assets isn't going to be the big deal that many think it will be. Since it is an area that has had much research in the past and there are many different techniques that we can leverage. The real challenge while be on the server side in determining which assets should be visible to the client and making sure that the client has the needed bundle by the time it is needed.

    @DaneCO20 - Yeah I looked at that LoD system in the asset store too but after watching the video and seeing the lag spikes as LoD assets start loading in (At one point they even mention it) I realized that they are either suffering from the the garbage collection spikes or mesh collider issues that I've been fighting for months. Since this new system seams to avoid those issues fairly well I will most likely integrate those techniques into my own system. Which of course all of you will have the pleasure of watching once I get it working.
    Last edited by chronos78; 07-14-2011 at 03:14 PM.
    “little expense has been spared to give the impression that no expense has been spared.” - Douglas Adams

  8. #8
    Join Date
    Jun 2008
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    1,088
    Sounds awesome! Can't wait to get into this new system. Thanks for the quick response and the awesome VTMs.

    -Dane
    You know you want to!

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