Polygon decency!

[saddletank]

I've noticed a completely different ethos that UK modellers use vs US ones, and I have no idea why this is(*). On this side of the pond we generally try to shave poly counts down to the bare minimum, simplifying and deleting wherever we can. On t'other side modellers tend to be proud of a high poly count.

These are gross generalisations of course but if you were to randomly d/l 50 UK diesel models from UKTS and 50 US ones from T-S.com and run sfm on them to check I guarantee the US models would have a higher average poly count.

And this isn't down to styling either, such as grab rails, couplings and steps. But basic things like bogies, louvres and so on common to all engines.

* having said that I have many high poly-count US models on my PC and the routes I run them on generally give a higher frame rate return than lower poly count UK models run on UK routes. This might be saying 2 things: either we UK route builders build less efficient routes (which I doubt looking at the equally high poly count of US made static scenery obects) or US routes have a generally lower scenery density.

[Timcourt1]

Martin,

I would go for the Latter on the scenery density, take a look at swindon and then look at some of te US Town routes, the buildings here are just more spread out (I tend to prefer the term "Sprawled" )

[jimmyladd]

A class 22 bogie is a quite open affair, and a class 21's isn't. Can a reduction in poly count be made by the fact that you carn't see the wheels to well? (class15&16 models comming soon, Ha!! not unless somebody gives me a brain transplant!)

[CaptainBazza]

The TS graphics engine has its limits. When that limit is reached some poly faces are not rended at certain POV, the results are bizzare, semi-naked locos! The effect is most noticible on hi poly locos passing through hi-density scenery areas. The event also occurs on very high end systems.

The same problem of unrendered faces happens in hi-detailed 3d cabviews* irrespective of the scenery density.

(*A.K.A. the paxcam view 5)

[trackdancer]

I've noticed a completely different ethos that UK modellers use vs US ones, and I have no idea why this is(*). On this side of the pond we generally try to shave poly counts down to the bare minimum, simplifying and deleting wherever we can. On t'other side modellers tend to be proud of a high poly count.

These are gross generalisations of course but if you were to randomly d/l 50 UK diesel models from UKTS and 50 US ones from T-S.com and run sfm on them to check I guarantee the US models would have a higher average poly count.

And this isn't down to styling either, such as grab rails, couplings and steps. But basic things like bogies, louvres and so on common to all engines.

* having said that I have many high poly-count US models on my PC and the routes I run them on generally give a higher frame rate return than lower poly count UK models run on UK routes. This might be saying 2 things: either we UK route builders build less efficient routes (which I doubt looking at the equally high poly count of US made static scenery obects) or US routes have a generally lower scenery density.

Interesting observations, but here is the low down based on past projects:

UK routes have a much higher object density per square mile than a US one in general. That said UK trains are normally a lot shorter than a US one in terms of number of cars. This means that in terms of poly expenditure, US modelers can fairly safely throw 5000 to 7000 polys on the locomotive IF the rest of the consist (the wagons) are comparatively simple which fortunately most box cars are. With a train 100 units long, you could easily splurge on the caboose at the other end as (assuming you have LODs in place for the locos) the locos can hardly be seen in the same view.

For UK routes, this is a little more tricky especially with steamers which just begs for all the extra details. But it can be pulled off with the proper use of transparencies and especially smoothing groups as both of these can cut down drastically on the polys without sacrificing quality of details. One thing though, and I have seen this time and again are UK station models which are far more detailed shapewise that they really need to be - and here LODs do not really help if you think about it. On numerous UK routes the sim grinds to a virtual halt on my system when a train approaches a station. My strongest suggestion is to plan ahead when designing areas with high object density. Keep it simple, rely on textures for the details and do not model every doorway and/or window. I've even seen stations with modeled 3D fences! It is just not worth it if most users cannot experience the thrill of a train pulling into a station in a smooth manner.

If the station areas are properly designed you can everything you could possibly want plus detailed rolling stock. UK trains in general are not long, and given the extremely interesting nature of virtually all UK railroad equipment, a lot of these can be fairly detailed 3D wise if you look at the overall poly allocation for a scene. UK wagons are not necessarily more complex than their US counterparts. So if you allocate say 15-20000 polys (max) to a scene including everything you should be fairly safe and can include everything that you could possibly want to include on a UK scene.

Design for your locations. Complex station models in a relatively sparse rural areas will work fine and would be a good design choice as there will not be that much to look at in any case. In a more densely populated area, cut back on the poly allocations to the station and distribute the difference to the ajoining lineside structures. This evens out the count so in effect in both instances you can have your cake and eat it too.

This also means that you can have more detialed DMUs which would be nice and especially since these are normally short. Dave's DMUs are very efficient, but I've always felt he could easily expend at least 1000 more per model if the rest of the scenery had a more prudent poly allocation strategy.

Ohhh ... also it helps big time to map multiple models to the same textures as far as possible. Hard to do for individual subjects, but easy if the models are part of a combined set.

It's a tough one, having had the good fortune to work with both UK and US designers. In the final analysis, everyone does come down to the same considerations with regards to the polys, but regional geographic differences can and do vary the final outcome.

Look at it this way, if I take a train from Sevenoaks into London, every 1/2 mile or so the scene changes considerably. On the other hand taking the train from San Bernadino to Barstow, things do not really change that much. Once outside of the urban areas (which in themselves can vary from dense to low density) once you hit the "open roads" there is not really that much to see. I regularly drive an hour and a half between Riverside and La Quinta (near Palm Springs) and there really isn't that much to see especially from the perspective of the train as these tend to go thru industrial areas in the high density areas; in MSTS terms these are just large simple warehouse blocks; and then there is a whole lot of open desert with a highway, a few scattered buildings and structures here and there in small clusters. Most of these in MSTS terms are distant structures which could be modeled in very basic forms. You cannot normally do that in a UK enviroment as there will be a lot of detailed scenery much closer to the tracks, making scene poly allocation a must for any serious route construction (which incidently is why I provide polycounts and LOD info with most of the models I have released).

[saddletank]

Yeah, that's a very wise answer and probably the truth as far as the prototype goes. While lots of rolling deserty grasslands in a US route really brings out the atmosphere (as long as good terrtex have been used) a similar treatment in a UK route just looks bizarre. The UK rural scene is as densely featured as the urban scene with farms, field hedges and walls, copses, etc. The art of a good UK route is to depict this variety and interest of rural scenery without strangling your PCs RAM or video card. A UK route that doe snot attempt to model the density of the rural scene just does not cut it with me.

On the other hand when a route does arrive at it's flagship terminus station the route builder quite naturally wants this to be an impressive location, so it's a difficult choice as to where to draw the line in what is essential vs what is a luxury.

[trackdancer]

Yeah, that's a very wise answer and probably the truth as far as the prototype goes. While lots of rolling deserty grasslands in a US route really brings out the atmosphere (as long as good terrtex have been used) a similar treatment in a UK route just looks bizarre. The UK rural scene is as densely featured as the urban scene with farms, field hedges and walls, copses, etc. The art of a good UK route is to depict this variety and interest of rural scenery without strangling your PCs RAM or video card. A UK route that doe snot attempt to model the density of the rural scene just does not cut it with me.

On the other hand when a route does arrive at it's flagship terminus station the route builder quite naturally wants this to be an impressive location, so it's a difficult choice as to where to draw the line in what is essential vs what is a luxury.

You've hit it right on the head in the last paragraph. It's damned if you do and damned if you don't. It's some of the things that makes UK routes such an interesting challenge to do really well. It is, however, probably one of those things that may have to wait till the technology is generally available before designers like yourself will have the true freedom do do as you must truly wish to do to bring out the full essence of the route.

[saddletank]

I will be the first to admit that my depiction of Swindon station and its surroundings is probably more than most PCs can handle, but it is built using a lot of clever tricks, LODs, draw distances, etc to cut down on poly count and more importantly object count.

While more powerful PCs is one solution (and which is a certainty given a year or two) I don't think MSTS 1 is written efficiently enough to do any detailed urban location justice simply because of the way it stores tile and object data and loads and unloads them into the computers memory.

A rethink of the game engine is needed to get us where we want to be in terms of more detailed virtual worlds and for that I hope MSTS2 will deliver. FS2004 engine anyone?

[micksasse]

If you are pressed to save polys use "square wheels". When done properly these are more "rounded" than polygonal wheels.

I usually use rimmed wheels with 16 sides, making a total of 64 polys for the rim and tread, then 4 more for the front and rear faces for a total of 68 per wheel. Axles I tend to use either a 6 sided or more usually 5 sided shape for a total of 10 to 12 polys.

Thus, a complete wheelset is about (68*2)+12=148 polygons and looks fairly decent. With "solid" wheels the total comes out to about 268 polys, so the savings are considerable.

Agreed, compare the wheels on the HST to the wheels on the 365, (while I m not sure of the poly counts), but the 365 has circular wheels, and the HST square wheels, the HST wheels look much much better, and certainly would be less polys than the normal wheels that were that 'curved', also helped by the fact I was able to 'smooth' the rims.

Many thanks for the above, and for the other posts (apologies for not acknowledging them; I've been away from the fora for a while).

Pardon the stupid question, but I don't understand what you mean by "square" as opposed to "polygonal" wheels - a word of explanation, please? (preferably a word of one syllable - duh!)

Thanks a lot.

BTW, Jimmy,, yes, there's something in that about the 21 bogie as against the 22, but, although i've just deleted a few polys, I don't think I can delete much more, and I don't trust myself to redesign the bogies from scratch (they're not mine but Tim Court's and I'm pretty sure I couldn't produce anything as good!). The spokes are achieved simply by texturing (Chris Baily's!), rather than adding extra polys by modelling them.

Subject to your guidance about wheels, I'm thinking of living with the poly count for now & will see if I can do better when I build a loco' from scratch. Apart from a few minor tweaks and making more economical use of texture files, plus getting permission to play with a sound file which seems to suit it, the loco's otherwise pretty much finished.

Talking about minor tweaks (and I suppose this is stricly off-topic, though it's still about building the loco!), on bizarre thing has happened: In TSM, the wheels are in the proper place, i.e. they sit on the rail and their centres are where the axle-boxes are on the bogies. But when I export the model into a MSTS object, the loco's wheels are all off-centre, and slightly off the ground! (That is, the wheels' centres are not where I left them in TSM, either in the Y or Z axes - the X axis, i.e. left-right, is unaffected as at least the wheels are on the track - or rather just above it!) Any thoughts, anyone?!

Cheers

[buffy500]

The basic diference is that 'normal' wheels will have circular faces on the end (ie the wheel end), on square wheels, a big flat square poly creates the end face, and then using transparency you make the face round.

[micksasse]

The basic diference is that 'normal' wheels will have circular faces on the end (ie the wheel end), on square wheels, a big flat square poly creates the end face, and then using transparency you make the face round.

Ah, right, cheers, Dave - it is sort of obvious when you put it like that! Presumably I'd use a transparent material in TSM and only apply a texture to the round bit?

BTW think I've already seen the answer to my second query (wheels in the 'wrong place' on the TSM forum - sorry for posting a question which had already been answered - and into the wrong forum!!!

[jimmyladd]

Hi Mick,
Just to change the subject slightly have you thought about modeling a class 29 rebuild of a 21 as well? I know there is a class 29 already on trainsim but I think it is modelled on the model train that Hornby produced some years ago which had some inaccuracies(I think thats how you spell it!). These seem to have been repeated on the msts model (It should be 2tone green for one thing).
Cheers, Jim