First of all, you need Rail Simulator/RailWorks installed, since I think you might still have Rail Simulator, you need to find a copy of the RSDevtools from http://railsimulator.com/en/railsimfiles and install them.
Rail Simulator and RailWorks take the .ia and .igs file formats. .ia is for animation and .igs is the solid scenery. When you make a model, the texture needs to be applied in a .bmp or (?) format, and the texture for the game is in a .ace format. (Also a square sides too. ie. 512x512, 512x1024, 1024x1024, 1024x2048, or 2048x2048 or bigger/smaller) To export in 3DCanvas you need the professional version for 70 USD. (And the trainworks crud with it too.) You then need a source folder in your main Rail Simulator/RailWorks Directory. Then below that directory is Source > (Provider name) > (Product name) > Scenery > Categories such as buildings, audio, rail network, vehicles, etc. > "Asset" Which is where your .igs and .ia files go, also the .xml file, which the last one below that is the textures folder, which holds your .ace files.
An object going from 3DC to RS/RW needs to be minimum a textured object. It can get more complex as you add shaders (or modifiers if you wan't to call them that) and add shadows and lod's and stuff on that level.
Now, for the export,
In the blueprint editor window find your simple box in the folder structure.
Step 1 – Right click the IGS icon (which looks like a light blue box with orange triangles either side)
Step 2 – Click new scenery blueprint
Step 3 – Move the slider till you see scenery blueprint, click OK
Step 4 – Click the preview button, and your simple shape will appear in front of you.
Step 5 – In the Name field call it ______
Step 5 – In the English field call it ______
Step 6 - In the Category select Domestic buildings
Step 7 – In the first Blueprint set ID fill in the Provider and Product make sure they match your folder structure. (Your devealoper name) as the Provider and (product/project) name as the Product
Step 8 – Click save and then export.
Step 9 – Close the Asset editor then run Rail Simulator.
***Step 10 – Open up your route in free play.***
Step 11 – Click the World editor button on the bottom tab (looks like a globe)
Step 12 – Click open the middle tab on the left hand side and click the set object filter (looks like a blue cube with an orange arrow)
Step 13 – Pin open the tab on the right hand side and click on the grey arrow next to developer.
Step 14 – Select provider (your provider name)
Step 15 - Select your product and tick the box.
Step 16 - Find the object under the house icon in the top left tab and place it in your route.
Then you can click the orange arrow to save.
***You need a route to place your objects in, if you don't want to use the default one, click "New Route" on the main page and select a route template to work off of.
If you need more help feel free to ask.
Alex (Your welcome?)
Brave the forest, brave the stone,
Brave the icy winds and fire,
Braved and beat them on my own,
Yet I'm helpless by the river.