Graphically Destructive?

[decapod]

Fair enough - but can you point me at just 1 typical loco which is well detailed and only uses 2 off 512x512 textures ?

Now there are 2 highly subjective terms there which could lead us into more debate - typical and well detailed.

By "typical", I mean something more sophisticated than an unlined 0-6-0.

By "well detailed" I mean to avoid texture blurring for all but insignificant details.

Not typical by your definition, but my GWR Class 850 unlined 0-6-0 uses a single 512x512 and has every rivet covering the saddle tank ( plus I'd consider it well detailed)

Most people forget that those little models take almost as long to build as the big ones and are similarly detailed.

My 517, similarly detailed, uses 2 (partly because of the 2 versions, one ACE is shared)

However the Dean goods, with tender and snow plough, was only 3 total - an that is a more detailed model.

My J94 used 3, but Dave's latest "special" went to 4.

I would say 4 or 5 is probably about right for typical detailed (by your description).

I do look at some locos though and am amazed at how little stretching/re-using of textures is done and how sometimes an area of texture is too detailed (another subjective issue) - a lot of them could be more efficient.
(my recent tests show stretching improves performance quite a bit too)

David101's coaches was an interesting idea where you have a set that are likely to be together, I may even excuse the use of 1024 textures there
It is possible that MSTS may find this slightly more efficient.

As for Daves problem ... it could be anything causing it - video card/driver/directX/MSTS it's an odd one (try getting a new driver? test on another PC?)

[Zorcan]

I should have known better than stick my neck out on this

My "typical" was a lined steam loco with outside cylinders etc.

On that basis, Decapod's experience with textures seems in close agreement with mine.

[decapod]

Very true Mick, we are broadly in agreement, though 4 or possibly 5 would be my absolute limit for a loco model.

It really all depends on what you need to texture and how it fits on the model.
The J94 "special" for Dave was an oddity as I needed asymmetrical tank sides with a lot of detail.

The Dean goods only uses 2 Ace files for the loco and has room to spare - and, if required, could be full lined out - if I built a Star or De Glehn I'd expect it to be also 2 or 3 at most.

[Zorcan]

Hmm,

I've used 4 textures in my Hall - and 3 in the tender !

If you can cover a Star in 2 or 3 then either:

1 You're stretching some areas more than I would.

2 You're using a larger number of polygons to break the lining down into small areas.

The lining was the greatest single consumer of texture area in both the above models.

There is a trade off here, and I have no idea how the tradeoffs between texture area and polygon count breakdown.

My understanding is that, provided the total amount of texture area currently rendered does not exceed the graphics adaptor's memeory capacity, then there is minimal impact on frame rate.

Polygons, however, have a proprtional impact upto a point, then as overall model complexity rises above a certain threshold, an increasinglydramatic one.

This is certainly the case for some 3D engines, which I've worked with under other circumstances, but may not be the case with MSTS ?

[decapod]

I do tend to stretch/re-use areas more than most, but you'd be hard pressed to spot them on the models and my locos are generally less than 4000 polys (with "solid" spoked wheels and 3D suspension)

With my latest research into polygons, it seems they are not quite as important as first thought - there is some kind of geometry optimisation in MSTS which means certain shapes work much faster than others (more on this in a week or two)
One thing I can say is that DXT compressed textures perform much better (50% better?) than any other format (at least on GeForce cards they do)

You're right about textures not having much impact but there is some (with texture blending of pixels into texels) - basically your thinnest line on a texture should ideally be 1 pixel wide, though other factors like "dirt" pixel size may play a part in the decision.

I (and others) are also starting to worry about MSTS's ability to handle too many textures as the routes become more complex. (though this shouldn't affect your own decisions on how to use them on locos)

In the end, like most of these discussions, it's down to the builder, Marks initial comment was probably based on smaller locos and stock (?) and he's done wonders with covering large models with very small textures.
Many of our highworth wagons use a single 256x256 texture and 10 of them probably has a bigger effect than the single loco pulling them.

[bravedan]

Some good stuff emerging..............but now, as DXT compession has been mentioned........a comment from someone with huge experience of MSFS and MSTS graphics......which rules me out straight away.......!!!!!!!

"For non-square images (or images larger than 512x512) MakeAce will only provide a 1-bit transparency (ie "on" or "off" ) so shades of Alpha over 50% transparency will go to 100% while those under will go to 0%. "

To me this means translucency (dirty/tinted windows, etc) won't work with these types???

a further quote from the same source...........

"Also you don`t want to use DXT compression on the image as DXT only allows 1-bit transparency as well."

So, no dirty windows etc on DXT compressed images??

I also have been led by comments in US forums to believe that (I don't have proof, OK?) DXT compression also simplifies the colour palette used within the Sim, so a complex shaded image may appear as a much more coarse banded gradient fill/shape.

Does possibly explain why DXT appears to raise frame rates......as the graphics engine is only having to resolve 1 bit depth.......unless you know better???

[CaldRail]

Yes DXT compression loses a certain amount of texture information. Detailed textures are not well served by this method, although 'solid colour' textures ought to benefit. In my experience though DXT and transparency (1 bit) don't always work too well together.

Zorcan - Sorry I can't point at a suitable loco, but thats more to do with the fact I can't download any so my loco shed is nowhere near as comprehensive as some peoples.

As for sticking your neck out, if you sincerely believe something to be right then do so. I didn't get these third degree burns for nothing you know!

[decapod]

Dave...

DXT1 compression doesn't change the pallete, but does cause some odd colour effects with its compression technique..

True - no translucency is allowed, only transparency with DXT1 and they must be square

(there are 4 other DXT* formats that do support translucency - maybe in MSTS2 they'll use them)

They are generally faster because of their smaller size and the fact that GeForce card can handle them in "native" format - other cards may have to convert them first.

Still a good idea to use them where you can... basically try and see what they look like.

[robin]

On my locos I usually use 2-3 512X512 textures and most of them are lined. Polys, textures or any resource I think its generally best to use the minimum possible to obtain the effect your after. I am also (with a few tests I have done) beginning to think that too much use of transparent shapes has an effect on frame rates.

A lot of multi texture locos I have looked at waste a lot of texture space. There is a a good deal of background showing and with bit more thought and re-arrangement more could be got out of a texture with out much loss of Pixels.

[CaldRail]

I've always found that transparency isn't too bad - its alpha translucency that slaughters the frame rate.

[timbooth]

One of the best ways to add detail to a model is to superimpose smaller polygons just above the surface (5mm or so), and use transparent textures - this works well with things like loco numbers/names, and fine detail lining which can be 'tiled' using a much smaller bitmap size. Alternatively, you can break up larger polygons into smaller ones to achieve the same result.

I'm going to optimise my 57XX pannier tank, and future models, in this way, rather than using 1024x1024 textures or multiple 512x512 texture files. I'm also applying this technique to station buildings which have lots of repeated features such as doors and windows - instead of creating a bitmap with a scale layout of the building walls and roof, I just use a plain tileable brick wall texture for all the walls and create polygons where all the doors and windows are, and texture these separately using a few window and door patterns. This saves a huge amount of texturing, and means the same texture file can be used for similar buildings. It also means the windows are doors can have much more detail - and you can add recessed windows/doors which improve realism (not many buildings have flush windows). This increases polygon count slightly, but not enough to affect fps the same as multiple large bitmaps will.

Keeping the number of texture files per shape to a minimum means less swapping of textures between disk and video memory, which improves fps.

[fadedGlory]

Just to get briefly back to near the original topic, I find the 'cannot add car to world' message a particularly frustrating one, since it is so unhelpful. There appear to be so many reasons why it springs up, but you're entirely on your own trying to find out what went wrong.

My latest lttle loco which I thought was OK has now too been hit by this bloody thing. There is something in it that MSTS doesn't like, but what is it? Too many polygons? Too many parts? Too many parts hanging off the same parent? Too complicated hierarchy? Wrong kind of snow? Bwah. And I haven't even textured it yet!

What we really need is a modelling program that properly checks the models for problems without having to actually load them into MSTS, and then comes up with clear, reliable diagnostics as to what the problem is. That would save us many long nights and a few hairs too.

Back to the laboratory, to disassemble the whole thing and build it back up, bit by bit.

Bah.

fG

PS I understand that that new Colorado & Rio Grande loco from Fozzy Bear has 14 .ace files!

fG

[fadedGlory]

OK, I've calmed down now

I DID have to split the thing in bits and save them off, then rebuild it. I combined a few bits that could be combined w/o hurting the texturing too much.

I ran the 'orphaned points' and 'check part geometry' thingies, and to be fair it did found some problems that it then repaired.

Resetting all boiler fittings to parent 'boiler' and all the rest to parent 'main' seemed to have done the trick.

105 parts and 6689 polygons after conversion - it runs again.

Texturing under way - keep fingers crossed, Friday 13th is almost gone

fG