How much is too much?

[SMMDigital]

This question has been asked a hundred times, but there has never been a clear answer on it.

I've blown the poly-budget, big time, on the C39-8, and it stands at about 28,800 right now. I've run it on my computer with a single graphics card, and with multiple units, and have had no stuttering issues. However, there is one detail that I want that will add realism but will also add another 6,000 polys, even in it's simplest most optimized form.

So how much is to much? 35,000 polys seems be very heavy for a diesel locomotive.

[eyein12]

youre fine the sd60M I finished up pushes 40K with all the bells and whistles and I can put a ton in the same tilel and no stuttering.

put it in

[Kali]

It's a locomotive - not something there will be hundreds of at once - and it's also not 2006. 38k is fine. It's four freight cars - probably 3 freight cars even.

[MikeK]

I remember RSC stating a long time ago that one of their british steam engines that they were building had well over 100k.

[SMMDigital]

Lol! Not getting near that. 3DC is starting to groan under the weight of 35k, taking longer to load the loco and crashing more often.

[simer4]

I dunno, so far my C425 has over 50-60k.

[eyein12]

I dunno, so far my C425 has over 50-60k.

For people with lower end systems higher poly models will eventually start weighing things down. its still good policy to keep your model as low as possible adding in detail as you go. most mid-high systems will be fine.


I figured looking at your level of detail put on that thing. I was gonna ask. As I stated before you have to adopt a careful method of building when using sketchup because your model info may say 50-60K but when you export it as a 3ds or obj file you'll find that its actually far higher depending on how you built your model. try exporting as a 3ds file and see how many triangles you have this is the accurate figure your looking at when its ready for the game.

Ian

[Kali]

Don't forget serz won't build an igs of anything with more than 60k ( unless that limit's been lifted recently ) in one object.

[PamBrooker]

polys arent the real problem. its draw calls.. the more textures you use, and the more times you use them, creates larger and larger numbers of draw calls as the game has to read in those textures So, lets say you have a texture sheet for each of, your wheels, axles, body, this gauge, that gauge and god only knows something else.. well, to load those textures, the game has to open each texture file and read it each time that texture is needed.. thats a draw call.. Now if we take all those textures mentioned above and place them onto one texture file, you still get a draw call, but only one or two instead of however many as the file is already open for reading.. Your polys wont slow you down. its the textures tha'll kill ya..

[dogmouse]

I need a clarification about the number totals you guys are throwing around, please:

I am going under the presumption that the inside cab model triangle totals, and the exterior model triangle totals are two separate entities, correct?

For example, The loco im building has roughly 17K triangles for the exterior model, and 20K triangles for the interior cab model. The absolute total would be 37K, BUT...they're not drawn at the same time, so i should be ok, yes?

Just wondering,
Rich

[PapaXpress]

So Pam, what you are saying is that instead of using two 1024px textures plus some smaller child ones, it would be better to use one 2048px texture.

[SMMDigital]

You are correct dogmouse. The exterior model isn't rendered when you are inside, and vice versa.

[dogmouse]

Aw, thank you! SMD!


And Pam, I believe that is the very reason why RSC suggests to avoid assigning multiple texture sheets to the same object.

For example, all of the textures used for, say, a bogie, should all be on one sheet, so as to avoid opening up two or more sheets for the same object.

[hertsbob]

I remember RSC stating a long time ago that one of their british steam engines that they were building had well over 100k.

I think you'll find that would have been Sly (of IHH fame). Derek is a great believer in the 'less is more' philosophy, whereas Sly has always maintained that it doesn't matter at all how many polys a loco consumes.

As has been previously mentioned, you're not really going to have that many locos all in the same place at the same time so it's not too much of an issue; what's more of an issue is trying to have large yards full of (relatively) high-poly wagons - that really is a sim-killer.

Cheers

Bob

[Kali]

So Pam, what you are saying is that instead of using two 1024px textures plus some smaller child ones, it would be better to use one 2048px texture.

It's best to get rid of the smaller "child" ones first, perhaps by filling corners of one of the bigger ones. Doesn't matter how big, switching material ( and I'm pretty sure it's materials rather than just textures which need draw calls ) when you're drawing the scene costs the same. Once upon a time 2048^2 textures would have hurt because of memory speed limits,( and sheer VRAM limits - they're enormous when they're uncompressed ) but I think we're a bit beyond that now.

Unfortunately autonumbers and so on rely on using different materials, just have to live with that.

I would imagine one of the issues with using tons of wagons in a scene is that they're not LODded very well.