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Building A Model With Strips And Skins Part3

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  1. 1 Building the 3D model
    1. 1.1 File Headers

1 Building the 3D model

We set out the basic structure in Building A Model With Strips And Skins Part1:

This is going to be a relatively simple model, so you may well prefer to keep all the bits in one file. For more complicated models it can make life easier if you split the components into separate files

Open the Rail3D Editor. Create a new model in the appropriate place in the Stock hierarchy, i.e. the same folder where you saved the texture file.

  • Add at least a Name statement and an [End] for each component in the tree.
  • The blue items should have the Hide keyword and the orange items the Component keyword.
  • Give all components the Metric keyword

After saving the model file in this form, it is a good idea to rebuild the stock library, so that the Rail3D Editor knows about all the new components and will display them correctly in the preview.

1.1 File Headers

At the top level, the Unit definition for the Munich_UBahn_A model is easy: just one line for a description to appear in the stock library when the user selects the model, and another to specify the composition of the unit. I decided to build both car sections with the driving end at L=0, which means I need the “!” modifier to reverse the “a” car. (I could equally well have done it the other way round, or, at the cost of a little extra complication in the models, avoided the need for the “!” modifier altogether.)

Note that I use “&” to link the car sections — this tells Rail3D to treat the unit as an inseparable combination, i.e. to count it as a single vehicle when uncoupling or dividing. 

 name	Munich_UBahn_A
 Description	Original series built 1967–1983
 Unit 	!Munich_UBahn_Aa&Munich_UBahn_Ab

 [end]

Notice that we are taking the position of the front coupler as our reference point L=0 For the individual car sections, we need a bit more information.

  • As I said earlier, we don’t want them to appear in the stock selection dialogue, so we use the Hide keyword (Component has the same effect).
  • We are going to work in cm, so we need the Metric keyword.
  • From the drawing, I can work out that the length over couplers is 18570 mm and the distance between bogie centres is 12 000 mm. This gives me the Length and Wheelbase.
  • The numbering system is not straightforward: the first digit is “6″ for “a” cars (at the North end of the unit in service) and “7″ for “b” cars (South). The last three digits give the unit number, but with gaps between the different batches of cars. For the sake of simplicity, I decided to use numbers in the first production batch, A2.1, ordered in 1969, which start at 6101/7101. (If you have more than 51 units on your layout you will get numbers in the non-existant range 152–160, but there’s not much Rail3D can do to prevent that.) The corresponding Number string for the “a” car is 6101 %4d.
  • As the dynamics for non-steam vehicles are currently being improved, I won’t discuss the various dynamic parameters (Max, Power, Weight, te, Brakerate) in detail, except to say that the values mostly come from Pischek & Junghardt.
  • These cars have a central driving position. The Cab parameter defines the drivers’ eye-level — from the drawing a point 160 cm back and 230cm high looks reasonable.
  • Finally, we need to insert a reference to the Skin texture we spent so much time making, so that Rail3D knows where to find it! 
 name	Munich_UBahn_Aa
 Hide
 Metric
 Length 	1857
 Wheelbase 	1200
 Number	6101 %4d
 Max		80
 Power		360 kW
 te		50 kN		#guess
 Weight		26 tonnes
 Brakerate	4
 Cab 0/160/230
 Skin	”Munich_ubahn_a.tga”

 [end]

The header for the “b” car is identical, except for the line 

 Number	7101 %4d

Each car section also needs to call the body, interior, and bogies (we can deal with the doors later). From the drawing we can read off the positions of the bogie centres as 330 and 1530 cm from the front coupler (double-check: are they 1200 cm apart? Yes!).

The interior and bogies don’t need to be visible when the car is a long way from the camera, so we can tell Rail3D to simplify the model at ranges greater than 200m by using the “

Warning: Make sure that you have followed the steps above to Name these components and add them to the library, otherwise you might get a crash when you try to preview your model 

 Include 0/0/0 	      Munich_UBahn_A_body
 Include 0/0/0 	 <200 Munich_UBahn_A_int

 Bogie	0/330/0	 <200 Munich_UBahn_A_bogie_outer
 Bogie	0/1530/0 <200 Munich_UBahn_A_bogie

Note that we won’t see any result from these statements until we actually build the corresponding components!

Mark Hodson August 12, 2005, at 08:25 am

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