Trainz/Before you start Performance and other issues

For your creations to run smoothly in Trainz it's best to know a little on how the program works.

The TC3 content creator's guide is the latest one available. http://www.auran.com/TRS2006/uploads/Image/files/CCGTC.pdf

Modeling guidelines http://online.ts2009.com/mediaWiki/index.php5/Modeling_Guidelines

Image texture guidelines

Compressed image formats such as .jpg are good for storing images because file sizes are small relative to images stored in uncompressed formats such as .bmp, .png (Portable Network Graphics) or .tga (TARGA). However they are not good for Trainz as they need to be decompressed on the CPU which degrades performance. .tga or .bmp files are best as they do not have to be decompressed.

TRS2009 handles textures differently than previous versions of Trainz. TRS2009 transparently compresses textures by a factor of four so you can use larger texture files for the same performance. .jpg texture files are not a problem in TRS2009 but be aware that because they are a compressed format, the quality degrades each time they are saved.

Normal mapping

Normal mapping can give added detail without putting extra load on the cpu, its fairly easy in Blender and is supported in TRS2004 upwards. Technically TRS2009 handles it a little better.

Level of Detail (LOD)

LoD (Level of Detail) Chris Bergmann Auran:

"A decent rule of thumb might be that each lod should shave off at least 50% of the polygon detail, and that LODs below ~500 polys are not worthwhile unless you expect the item to be static and present numerous times in the same scene. (For example, a tree or generic house.)

More LODs means more memory usage and more CPU/GPU time in order to swap the LODs in and out as appropriate. You want to make sure that the time and memory lost in LOD swapping is more than compensated for in the polygon savings. Small polygon gains just don't make sense in this light."

Performance issues

Each texture file incurs an overhead of roughly 200 polys equivalent so keep the number of texture files to a minimum, preferably one unless using a normal map then two.

To load anything in Trainz incurs an overhead of roughly 300 polys equivalent, Chris Bergmann in Trainzdev, so a block of houses has a lower overhead than six individual ones.

When building a layout select large items that use .tga or .bmp texture files and ideally just one of these. Try to avoid items that have thirty odd .jpg texture files. That nice simple 120 poly building is carrying a hidden unnecessary 6,000 poly overhead.

Locos and rolling stock often use scripts these weren't protected from each other in TRS2004 and often two items that work separately will cause TRS2004 to crash when used together. Later versions are better for scripts.

Heavy smoke kills the frame rate so use it as lightly as possible from as few places as possible.

TRS2009 is very good at spotting errors that can cause problems even in other versions. Use CM2 to error check your work.

Last modified on 7 September 2011, at 23:45