View Full Version : What is the difference between trees and no trees in fps??
05-04-2006, 03:02 AM
I noticed that when we all (trainsimmers) simulate any freeware or payware route with trees background get very low fps like between 6 to 12 and without trees in background get high fps like 30 to 50 fps. Why are the trees affected the fps in simulation?? Can anyone explain this why does fps affect the routes with trees background??
05-04-2006, 09:48 AM
Hi John !
The more objects there are in a route and it does not matter whether they are buildings, vegetation or rolling stock, the longer it takes MSTS to draw them into a scene, using the appropriate WORLD files and associated with them shape files and textures.
The more there are the more work MSTS has to do fetching them from the hard drive and unless you have a fast Graphics card and at least a 7000 rpm hard drive with a large cache will find frame rates slowing down in areas cluttered with them.
Forests containing many trees are one object, but stand-alone trees are just one. 100 individual trees take a hundred times longer to display than one forest containing the same amount ! ;-)
O t t o
05-04-2006, 10:01 AM
Well as with other models in MSTS, it is always better to combine several objects into one forming tree "clumps". One thing I absolutely HATE with MSTS forest objects is that you still get somewhat loosely spaced trees. Also missing is the undergrowth so that forests often look like a well maintained park.
Hence my suggestion for making prototypical forests is to combine various different or similar trees into one larger group of trees and some undergrowth (bushes etc.) and place those in a group (or as a forest???). Combine that with tree lines (scenery backdrops) and you should be able to get a decent forest that should be easy on the tile count.
It all is more difficult of course with heavily mountainous routes where you look DOWN on forests. Here forest objects maybe the way to go to get some 3-dimensionality and the rest ought to be covered by a good ground texture.
What I really liked for undergrowth was a technique which is possible in Trainz is - I think - called a clutter mesh. It basically is a ground texture, which can be painted on the terrain, which generates dynamically pre-defined low-poly models (e.g. bushes). This was great for modelling undergrowth in forests!
05-04-2006, 01:02 PM
> Hence my suggestion for making prototypical forests is to combine various different or similar trees into one larger group of trees and some undergrowth (bushes etc.) and place those in a group (or as a forest???). Combine that with tree lines (scenery backdrops) and you should be able to get a decent forest that should be easy on the tile count.
Some of which are available in the file library. As for forrest regions, you can only assign one texture per region, but of course you can vary it in size (last two values in a forrest.dat entry are the min/max scaling factors), and overlap different forrest regions to generate the variety.
However, it is not only the "object count" or .w file size that is important in terms of fps. Tile size is mainly an issue when MSTS loads the next tile, with stuttering occuring if that is a huge file. Do not to forget that performance-wise, the most crucial factor is and remains the graphics, and this is by 80% or more affected by the resolution of texture files. It does make quite a difference whether you use 512x512 or 256x256 textures for a tree or a forrest region...
A realistical variation in vegetation requires you to use several different types of trees, both in the form of single shapes and forrest regions. If all of them use 512x512 textures, then the hit on fps will become an issue with slower machines. That of course applies to any scenery object, with the complexity of the shape (number of poly's) also contributing to the problem, but to a lesser extent.
In the case of my laptop, resampling all tree textures of a route from 512x512 to 256x256 and unsharpening the texture (0.3 pixel radius, 200%) has doubled my fps from 8-10 to 16-22, with no visual impact unless seen from very, very close...
Lukas a.k.a Swissie
05-04-2006, 05:28 PM
One disadvantage of using three lines and clumps is that their individual components do not align themselves to uneven terrain like those in forests do.
But superimposing different tree forests and undergrowth forests on top of each other or overlapping them comes close to reality !
Below an example of 5 forests on top of each other, 2 fir trees, a deciduous tree, a bush and grass, still giving 42 F.p.S. !
It's a lot of work doing that in a route the size of the MARIAS-KOOTENAI, but might do it for the MP3K-2006 ! ;-)
What I hope we will get with the new train sims is the ability to create forests with a mixture of vegetation and not just rectangular shaped ones. Mark the outline of it, no matter how irregular and then fill it with your choice of whatever to a feasible variety ! That could be herds of animals too ! ;-)
O t t o
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