Hi Nick - it looks like the problem here is MoI's display mesher is generating an excessively dense display mesh and consuming all available memory.

In MoI if you go to Options / View / Meshing parameters and set Mesh Angle to 20, and turn off (uncheck) Add detail to inflections, then this will complete. Actually you only have to uncheck that Add detail to inflections.

It looks like there is some kind of highly folded little lumpy thing at the top from MoI's result, that is probably what is freaking out the mesher.


Looking at your rail curves those are curves made up of 5 sub-segments (using Separate in MoI or explode in Rhino will show you those), and MoI does not do a good job with this kind of multi-segmented rail curve currently.

If you go into Rhino and use Rebuild on those rail curves with something like 30 points, and then take that now single-segment rails into MoI you will then get a nicer result in MoI.

So the main difference is that MoI is doing it as kind of 5 sub sweeps which is kind of chaotic with all the twisting around (and especially the end rail segment parts are tiny), while Rhino is doing the equivalent of rebuild/segment merge on the rails first.

I think I should be able to improve MoI's handling of this kind of multi-segmented rails, I have added it to my list of stuff to look into. But until I get a chance to work on it you will need to set things like this up with longer "single-segment" type smooth curves instead of having multi-segmented rails.

- Michael