its a little more complicated than that.
In the simplest of terms, a 3D modeling program can open up a b3d file made for BVE, but BVE can't utilize b3d files exported from a 3D modeling program without some hand coding in the b3d file itself.
Maybe somebody with a little more experience can explain in further detail, I don't do objects so I can't really help you beyond this.
Yeah it can. How do you think I got the bulged roof on the R62?
Before you make too much progress on the model, make sure you build it in meters. If you continue to build it in feet then it will probably come out microscopic in OpenBVE.
You could send it to me when you're finished with the model if you want and i'll convert it for you, but if you want to do it yourself then you will need everything posted below:
-Sketchup(Any 3D modeling program that exports .3DS will do, but I recommend this).
-Blender.
-Python(version 2.6 and above). Install into C:\Program Files\Blender Foundation\Blender
-This BVE Exporter plugin, found here:
http://www.bve-exchange.co.uk/forum/viewtopic.php?f=1&t=2681 Install in "Plugins" folder in Blender directory.
-OpenBVE(Of Course).
When you're done with the model, export it to .3DS(which the pro and iirc the free versions should be able to do). Run blender, import the model, and then export it again to .b3d(given you have the plugin installed). Save it to some place you will remember, and then open up object viewer. Your model should be right there waiting.
-A word of caution. Exporting to .3DS triangulates faces, making one square face two triangular faces. This helps when curving objects and for small details but then it tends to increase the poly count(number of faces on an object). The 160 model I have currently has 14,320 faces. If you want an efficient object make sure not to add too many details that will potentially slow down your game or others'.
BStyles