I've built some models which have all a common problem. If I export them with no distance levels everything works fine. If I use the option with 2 LODs MSTS crashes when loading the models with the report/not report requester. What can be the cause for this? Is it the count of objects, count of groups? Sometimes I have success with reducing one of those but when I compare models that crash and models that don't crash sometimes the latter have more groups and more objects. I can't find any pattern there. Any suggestions?

I'm not sure I can help with 2 LOD's but...

Vulcan Foundrys' ZC Diesel failed to load with 1 LOD due to a few very high poly count small objects in the main group - There may have been some coplanar faces or points very close together.

The solution was just to extract each object in turn to a new group outside of main and re-export/test.
Once found, rebuild the offending part.

I've had problems with 6 LOD's not able to export at all if there are any coplanar faces.

(A plugin to seach for coplanar faces could be useful)

Yes, that kind of utility would be good.

I agree a plugin of that kind would be useful although I'm not very confident that it would help with my problem. Quite often I do minor changes to a model and suddenly it won't load any more. I checked these changes on the last model with this problem and they cannot produce coplanar faces or points to near to one another. I simply added 2 cubes, deleted 4 faces from them and added texture which was used on the model before; nothing really new but it wouldn't load with LODs any more.

My main rule when building is [u]Optimize, Optimize, Optimize[/u]  8)

I use the operation whenever I do something Constructive or Destructive to the model - I think it helps to keep down this sort of error.

In the plugin front, I have just updated my Print Hierarchy plugin so it is much more useful now and could possibly help you spot the problem...
- it now outputs to a file, that is then viewed in Notepad.
- it also shows untextured objects and all textures applied to objects - this will help rationalise texturing so the groups are valid for export with the full 6 LOD's
http://www31.brinkster.com/decapod/plugins601.htm

I found sometimes creasing to be the source of problems. The 'crease all' plugin sometimes generates two named shaders and MSTS can't cope with that.

I think I don't quite understand. I thought the models had all 2 named shaders?

e.g.      shader_names ( 2
           named_shader ( TexDiff )
           named_shader ( BlendATexDiff )

I find in the acela.s.

2 named shaders is fine

TexDiff gets created if you use BMPs for texturing
BlendATexDiff - when you use TGA's or BMPs as masks

Tex, or BlendATex sometimes get created, but cause things to glow depending on lighting settings.

In my case I'm working on tracks, MSTS won't load switches or other animated tracks with two different named shaders. I'm working with the default .tga textures and the error is reproducable. In some cases creasing creates the second shader and this will result in send don't send.

All the default track pieces have 2 shaders, so I guess your problem may lie elsewhere.