Author Topic: Some Modelling Questions  (Read 1426 times)

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Offline ShadowPuppet

  • monkey/fish war person
  • 26
Some Modelling Questions
Writing up a tutorial for FS made me start thinking..... specifically about making sure I was putting down CORRECT advice on modelling approaches in teh light of the improvements to the FS2 engine.

Can someone advice me on the following....

1) Polycounts.  I know the overall polycount for ships can be prety massive under FSO, but are there limits on sub-objects et

2) Textures. I know that 'less is more' in terms of performance here. A few large texture maps are more efficient than lots of small ones. Is there a size limit ? Big textures, naturally, cause problems in terms of distribution...but you can't haqve it all ;)

3) Model construction. Before, there were certain 'don'ts' around how a model is constructed. The ones around making viable polygons would still be there, since they were not engine-specific, but there were others.
The old engine HATED intersecting polygons. Does the FSO engine allow them ? Saves a lot of bother when addign detail to a hull. You can make blocks that sit on the hull without having to cut holes and weld up the verts etc.
There was also a limit on the number of vertices a polygon could have. Still there?

A straight forward set of 'rules' for ship building would be a valuable addition to the tutorial ( and Wiki for that matter )

Can anybody help?
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Offline Bobboau

  • Just a MODern kinda guy
    Just MODerately cool
    And MODest too
  • 213
Some Modelling Questions
"are there limits on sub-objects"
nope, generaly more is good, keep your geometry even and you'r polygons roughtly equelateral, more verts == better lighing

"Is there a size limit ?"
not realy, keeping it below 2048^2 would probly be prety good idea though, make sure you use power of 2 sizes.

there is a limit of, I think 16 textures per subobject, you should use less than 5.

"...intersecting polygons. Does the FSO engine allow them ?"
it doesn't mind them, but that shouldn'd be reason to start packing cubes and spheres together and calling the mess a ship.
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Offline KARMA

  • Darth Hutt
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    • http://members.fortunecity.com/aranbanjo
Re: Some Modelling Questions
Quote
Originally posted by ShadowPuppet
Writing up a tutorial for FS made me start thinking..... specifically about making sure I was putting down CORRECT advice on modelling approaches in teh light of the improvements to the FS2 engine.

Can someone advice me on the following....

1) Polycounts.  I know the overall polycount for ships can be prety massive under FSO, but are there limits on sub-objects et
[/b]
sometimes ago it was said that there were a total limit of ~25k TRIANGLES. I also remember someone reporting random crashes with more than 7k x subobject, never got that personally (but it doesn't happen often to put more than 7k polys on a single subobject..)
Quote

2) Textures. I know that 'less is more' in terms of performance here. A few large texture maps are more efficient than lots of small ones. Is there a size limit ? Big textures, naturally, cause problems in terms of distribution...but you can't haqve it all ;)
[/b]
the limit is the limit of your graphic card. afaik, if your card doesn't support a size, it'll be scaled down. So if you use a 4096 texture but your card support 2048 max, the texture will be scaled down to 2048. IIRC all the cards that work with FSO support at least 1024, most support 2048, only few support 4096.
As Bob said, the limit should be around 16 textures x ship
Quote

3) Model construction. Before, there were certain 'don'ts' around how a model is constructed. The ones around making viable polygons would still be there, since they were not engine-specific, but there were others.
The old engine HATED intersecting polygons. Does the FSO engine allow them ? Saves a lot of bother when addign detail to a hull. You can make blocks that sit on the hull without having to cut holes and weld up the verts etc.
There was also a limit on the number of vertices a polygon could have. Still there?
[/b]
You can have intersecting polys almost perfectly rendered.
However, in my opinion a "true" edge look better than a "fake" one generated by the intersections of two faces.
Also, even if intersections are perfectly rendered by the game, there could be problems when converting the mesh, it really doesn't happen often, but sometimes the pof converters get confused by intersections and as result your model is not solid in game (you can fly through..).
In my experience, it may take really a lot to find the offending intersection, since the weirdest intersections you can imagine may work fine when a stupid minor and simple intersection may **** up your whole model, so be extremely careful.
Nonetheless I use intersections, sometimes, since they can reduce a lot the polycount. There are some for example in the HTL Fenris. Just don't use them without discretion, don't put 200 cubes and spheres together calling that a ship, as bob said.
Personally I make my model solid at first, then I work in polyreducing it making intersections and disconnecting submodels.
What does it mean to disconnect submodels?
for example, imagine a cylinder that starts from the base of a bigger cylinder. If you disconnect it you'll have two separated objects, and you'll save many polys deleting hidden faces.
When you convert to pof just glue together the two different objects, and they'll be considered a single subobject. You can do the same to make intersections.
Again, check the Fenris for an example of what I'm saying: open the model in truespace and decompose into objects.
This is a bit tricky, since too many submodels merged in a single subobject may crash the game. I got a model crashing with more than a total 130 submodels and working fine with less, I got another model working fine with more than 180 submodels..as you can see there isn't a true limit and when you start having crashes it could increase a lot the time you spend on the model trying to nail down the prob.
The other modelling limits are the same of the old fs2
« Last Edit: May 11, 2004, 07:58:51 am by 433 »

 

Offline Bobboau

  • Just a MODern kinda guy
    Just MODerately cool
    And MODest too
  • 213
Some Modelling Questions
the textures per subobject is a hard limit, not a sudjestion, the sudjestion was 5.

early HTL builds used a hard limit on loading the poly data, newer builds (after christmas) have used dynamic memory to load the models.
Bobboau, bringing you products that work... in theory
learn to use PCS
creator of the ProXimus Procedural Texture and Effect Generator
My latest build of PCS2, get it while it's hot!
PCS 2.0.3


DEUTERONOMY 22:11
Thou shalt not wear a garment of diverse sorts, [as] of woollen and linen together

  

Offline ShadowPuppet

  • monkey/fish war person
  • 26
Some Modelling Questions
Thanks guys :)

That makes things a lot clearer.

The intersection thing is a question of suitability. If you have two complex objects to 'join' then a boolean union is a recipe for pain ;) Just intersecting them saves polygons AND hassle!

From what you guys have said, use a continuous mesh whenever possible for best results, but when faced with a situation where a boolean would screw things up, try intersection.

Also, with regard to sub-models, I guess you get a feel for it. In terms of building, if you make a ship, find it has 5000 polys, then it should work fine as a single object, but might work BETTER if I broke it up a bit. If it had, say, 10,000 then it ought to be in at least 2 parts, but more would be better. Ultimately, I suppose you just have to try it and see :D
Victory for the Lightwave Liberation Army!

Down with the Truespace Tyrants ;)