How to tell LOD of assets?

I am interested in mostly trees, but I assume that this would also apply to any asset. How do I tell what the LOD of an asset is? Both downloadable and those already downloaded?

The reason that I ask is this (and it might help some others): I have decent equipment. I made a rather large (260 bases) layout and covered it with trees of all kinds. However, I was only getting 12-20 FPS with none of the settings on Ultra and the draw distance greatly reduced. I thought that maybe it was just too big of a layout. But, I saved that and then used the Bulk Replace thing and replaced every tree with one of the Alaska Cedar trees. Without changing any settings, I was now running 60 - 70 FPS!

One way to do it is using Content Manager.

Select the asset, right-click on it to bring up a menu of options, choose Open, then Preview. You should then see a view of the asset and LOD details (number of triangles). As you zoom out, that number will change (reduce) if the asset has a set of LOD meshes.

Thank you! That worked great. Unfortunately, it brings another question then:

I still have the same # of trees on the layout: all I did was change them to the Alaska Cedar trees: 5 different KUIDs. When I look at the triangle counts on thos cedar trees, they seem to be way higher than all the rest! So, why did my frame rates go up instead of down? Is it because of all the different trees? Does that put more load on the PC?

autodctr said:

Thank you! That worked great. Unfortunately, it brings another question then:

I still have the same # of trees on the layout: all I did was change them to the Alaska Cedar trees: 5 different KUIDs. When I look at the triangle counts on thos cedar trees, they seem to be way higher than all the rest! So, why did my frame rates go up instead of down? Is it because of all the different trees? Does that put more load on the PC?

Click to expand...

Trainz handles repetition very well. The number of different assets in the screen has an impact as each different asset has an overhead. Also speedtrees invoke the speedtree engine so all speedtrees is good, but one speedtree and the rest none speedtree is not so good for performance.

Cheerio John

What John said about repetition of a few assets being better than same total number of different assets is true, and probably explains your observations on frame rate, despite an overall increase in triangle count.

This is possible because triangle count is not the only thing your poor old computer must deal with. The other big factor affecting performance is the number of different texture materials that need to be loaded and rendered. The more texture materials, the slower it will be. I would expect that your 5 Alaska cedars used far fewer textures (possibly just one) than the number used by the many different tree models. It is quite possible that the texture effect was way more significant than triangle count in this case.

Content Manager’s asset preview spits out a statistic known as Draw Call. It’s getting a little beyond my pay-grade to explain this parameter, but as I understand it, draw call is related to the number of texture materials being rendered. I’ll leave the definition of a draw call (it involves chunks, which sounds repulsive) to someone more expert. Just know that the higher the draw call number, the slower the performance will be.

I guess a further factor would be the size and complexity of the texture materials. You could expect a simple material requiring just one 32x32-pixel RGB image to be less of a drag than a PBR material with two or three 2048x2048-pixel RGB/Alpha images.

Another way to examine an asset is to open it for editing. You can then look at all its files in detail, see if it has an LOD system, view the meshes, their triangle counts, texture material types etc. The suite of tools developed by Peter Villaume (PEV) is highly useful for this. In particular, Images2TGA for extracting .TGA images from .texture files, and Mesh Viewer 2 for examining .im meshes. Not all assets can be pulled apart like this - speedtrees and the new PBR/trainzmesh assets for example - but that still leaves a lot that can.

You will be amazed by the range of quality - from the early days when config files were an unregulated free-for-all and it seemed like a competition to get the highest poly-count and the most textures, to later efforts with just one or two photo-realistic materials and efficient LOD schemes.

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Thanks for the info!