I don't think RT3 would handle 5,000 tris on locos. It would be easy enough to test it and see what happened, but I think the frame rate hit would be too much. We were noticing some difference even with 2,000 tris, although it wasn't a huge difference. I do have a 4,000 tri model sitting in Blender. I could get that running as a test model, just for the heck of it. Although frankly I'm not sure there would be any point given that I can do just about any locomotive to a pretty good standard without going over 2,000 tris.
The real restriction in RT3 is the 1024x1024 limit on textures. Even if it allowed 2048x1024 it would allow heaps more scope for nifty things. I'd love to hack the .exe to allow that. Not only would it allow using fewer images overall, it would even allow cutting mesh without sacrificing visual quality, because the extra space would allow more scope for using alpha instead of mesh. So, weird as it may seem, allowing bigger textures could (providing you didn't go nuts) allow a performance advantage.
Anyway the Schools is now down to 1,780 tris. After saying I wouldn't take it further I went and took it further anyway. I sort of got on a roll and started seeing more opportunities to cut the tris, to the point where I then got into adding back in some extra detail for missing bits that weren't there before. For example, the firebox door on these things is a shallow cone, and although just using a flat plane with graphics worked well on the Pennsy H3 it didn't work so well for the Schools. The Pennsy has the large red numberplate (separate mesh) and a large headlight, which I think tend to draw attention away from the flat plane behind them. The Schools doesn't have those, so looks better with some extra mesh in the firebox door on the top LOD. Obviously it'll drop back to a flat plane by the third LOD.
Naturally all this did involve repacking most of the UV's again, but that's not as big a deal as it sounds. I'm now convinced that doing any loco from scratch is going to involve a complete repack at least 3 times, and you might as well accept it and just do it. Mesh really is close to finalised now. No, really. I mean it this time. Really.
![!DUH! *!*!*!](./images/smilies/smilie120.gif)
It's literally to the point where one or two tris might change, but apart from that it's just eye candy.
![thumbs_up !*th_up*!](./images/smilies/ok.gif)