[R H Steele]

In another thread ........ http://www.elvastowe...og-tree-ghosts/ ........ a suggestion was made to start a thread about this subject in modeling. So here goes.

I know nothing about modeling - just downloaded Tim Muirs Train Sim Modeler Project Files (tsmbrill.zip) to start to learn. Route and landscape modeling - way in the future.

Any examples of treatments of this subject, jpg screenshots of work, programs used for 3D modeling, discussions of physical demands placed upon software and equipment to render true 3D objects (like trees and landscape objects) in OR could be some of the topics discussed. Any other ideas?

One of my favorite routes is MLT LS&I with the upgrades by Nicholas Ozorak and Partners - a real fine job - makes a huge difference in the route. Would it be possible to make 3D landscape upgrades for MSTS routes to run in OR?

[That Genset Foamer]

There's some 3D Trees in the London & Port Stanley 2.0 Tree Update. All in all 20 drop-in replacements for MSTS shapes.

[disc]

When making such scenery that appears many times in the game, it's very important to make the models and textures optimized.
So use as few materials and textures as possible. For a simple scenery object like trees bushes, or houses, etc 1 material with 1 texture should be enough, but for the best ingame performance, it's better share and combine the textures for multiple objects in the same, compact texture file.
For example using a big 4096*4096 texture that contains texture for multiple objects, have no impact on ingame performance, but using multiple smaller textures for each object, or even 1 texture for 1 object will have serious impact on frame rate, as needs more draw calls to draw them. This is very important, as it's not possible or very hard to fix unoptimized shapes realtime in game.
Of course a single 4096*4096 texture isn't fits for all objects in game, so try to make those shapes share the same texture that are appear in viewport together. Grouping the textures of shapes that are never appear together in viewport, doesn't have any benefit.

Draw calls are expensive
Collapsing multiple textures to one in 3ds max (however i think when flattening uv maps at least 0.001 spacing should be used to prevent edge bleeding, and the textures can be compacted even more, by stitching some parts together manually after automatic flatten map).

Of course it's important to keep the polygon/triangle number as low as possible (while keeping the shape look good from ingame distance (as some are modeling things like it would be viewed from few cm which is an overkill in game, as there you view the objects tens of meters), but currently the performance limiting factor OR(and probably for MSTS) are the draw calls, not the polygon/triangle number.

So try to keep 1 shape 1 material and texture ratio for all objects in game, but even better to use the same texture file and same material for multiple objects.

[Hack]

disc, on 10 October 2014 - 01:17 AM, said:

When making such scenery that appears many times in the game, it's very important to make the models and textures optimized. For a simple scenery object like trees bushes, or houses, etc 1 material with 1 texture should be enough, but for the best ingame performance, it's better share and combine the textures for multiple objects in the same, compact texture file.

True to an extent. However, the biggest issue with trees won't be the size or number of textures/materials, but instead alpha stacking, a per pixel caculation, which can be compounded when using 3D trees. For example, a thousand buildings, each containing 100 polys and with several 512 x 512 textures is more efficient that a thousand single-poly trees sharing a single 256 x 256 texture with an alpha channel. The alpha calculations may be compounded by a 3D tree as you'll have several alpha layers for a single object while in view. Used sparingly though, such in foreground-only objects, a few scattered 3D trees among billboard ones (flat or cruciform) can be quite effective in bringing a scene to life:



Also note that the shape containing the alpha can be further optimized by not using a rectangle plane, but instead creating a few extra polys so that you can crop the shape closer to the outline of the texture's alpha channel and thus cutting per pixel calculations considerably. The 3D trees in the above image use several groups of "parasol" shapes for the leaf clusters (@ 16 tris each), which helps cut down on the number of overall polys vs. individual leaves, and each parasol is fairly close in shape to the outline of the image alpha (large cluster of leaves), thus reducing the amount of per pixel calculations.

Basic "parasol" group concept:



The parasols need not be so complex, nor does the trunk, as you'll find with more realistic textures and proper smoothing will allow for fewer polys to mimic the cartoon objects above or those that are more organic in shape. :cool3:

[James Ross]

Hack, on 10 October 2014 - 03:25 AM, said:

True to an extent. However, the biggest issue with trees won't be the size or number of textures/materials, but instead alpha stacking, a per pixel caculation, which can be compounded when using 3D trees. For example, a thousand buildings, each containing 100 polys and with several 512 x 512 textures is more efficient that a thousand single-poly trees sharing a single 256 x 256 texture with an alpha channel. The alpha calculations may be compounded by a 3D tree as you'll have several alpha layers for a single object while in view. Used sparingly though, such in foreground-only objects, a few scattered 3D trees among billboard ones (flat or cruciform) can be quite effective in bringing a scene to life:

Also, if you can use alpha masking instead of blending things will work out much better along the edges. You might need a slightly higher resolution texture for that.

[Simon E]

James Ross, on 10 October 2014 - 04:02 AM, said:

Also, if you can use alpha masking instead of blending things will work out much better along the edges. You might need a slightly higher resolution texture for that.

I think that this thread may have just shed some light on what is wrong with some of our objects, especially the famous Australian Sydney Harbour Bridge, that we made back in 2008, I have got a lot better with the modelling since then. I will dust the bridge off tonight, and revisit how we did originally did it. (It was from accurate plans of the harbour bridge, that you can obtain freely) But it is of no good, if we have not done it properly.

I hope to have it fixed, with trains and the highway running across it soon.

I also have other offending objects (not Australian) that need a good overhaul.

Thanks for this thread.

Simon.