Sketchup A Viaduct

Rail3dWiki — Sketchup a Viaduct

Recently I’ve been using Google Sketchup to model plans for an office reorganisation, and having got to grips with the software, wondered again about using it to create models for Rail3D.

I also needed some new viaduct models for my Swiss mgb layout, and as the prototypes have rather a lot of complex holes decided to try and model it with Sketchup. You can see a picture of the prototype at

http://www.photos-trains.ch/photos/picture.php?cat=442&image_id=1519&expand=2,125,126,442 and
http://homepage.hispeed.ch/LuWi/Bilder/Goms/Bett_MGB-Bruecke%20nach%20Betten%20aus%20Gondel.jpg (note in the second that the approach arches curve)

Modelling all those arches, especially in the curved approaches would be quite challenging in the traditional stock editor.

Modelling in Sketchup

Creating the model in Sketchup was fairly easy - as long as you read the manual!

If you’re going to try using sketchup, work through all the tutorials first. It doesn’t take long and it does explain how to do things like extrude shapes, cut odd-shaped holes in things and so on. Don’t skip the first tutorials - there are some important things in them. For example my first models were laboriously laid out with guidelines and careful adjustment. Later, I went back and did the first tutorial and discovered you can just type in dimensions!

I had to go back and look up how to cut a hole out of a curved solid to achieve the arches on the approaches, but it’s easy once you know how.

Next I applied a texture to the model:

For this I used a new texture that I had in my files and waiting for an application: a couple of times last summer when I was out with my camera and the lighting was good I remembered to point my camera at walls and things and capture some nice textures, this stone wall was once such photograph and works well on this viaduct.

Export to Rail3D

I had a little look at the various Sketchup / Google file formats to see if it was feasible to convert straight from sketchup to rail3d but in the end for simplicity used the msts route. There is an msts exporter for Sketchup and of course we can convert msts models to Rail3D format. So it’s a couple of steps, but quite easy to export the model to msts .S file and then run this through the Rail3D convertor to get a .stc file. A little bit of tweaking of the .stc file in the Rail3D editor and the viaduct is ready to use in Rail3D.

Fine tuning

I need to add some more detail to the model - such as handrails and possibly a deck. Although an alternative might be to apply the handrails as a linear scenery object to the track. This would avoid the fiddly business of aligning the track curve to the model curve and would mask any inaccuracies in doing so.

I think I’m probably going to go back to the start and do it again from scratch - comparing it with the prototype photos it should be a “thinner, lighter” structure, and I might try and use the methods in the Sketchup “model from a photo” tutorial. Anyway, there were a lot of false starts in my first attempt, so it would be sensible to do it again properly.

Conclusion

All in all a very quick and easy way to model things like viaducts and I shall certainly be using this process again. I tried modelling a loco once before (with an earlier version of Sketchup), this new version has better texture tools, and I might have a go at stock modelling with it.

The Skechup > msts > Rail3D route works, but it would be nice to have a direct Rail3D plugin for Sketchup. Sketchup plugins are written in Ruby - any volunteers?

UPDATE, there is a Sketchup Rail3D plugin now, so you can export a Rail3D model straight from Sketchup

mrg