The images show the steps I want to follow to make my train body (I am skipping some details such as wheel well or pantograph well).

I have to include doors that are not flat and that are not at the same level than the outside body.

doors can be seen here :
http://amabilis.com/eve/forums?a=tpc&s=2396098374&f=7046019974&m=48610435811&r=48610435811#48610435811

At each step, I'll have to trim unnecessary faces (trim operation) + optimize operation. I keep different faces for different texturing (within MSTS limitations).

8) mirror operation for doors body part and for body parts with windows
9) Union of the body parts
10) Add doors and create animation
11) Texture

Thanks in advance for your feedback.

3DCsteps.jpg (48 Kb, 233 downloads)

I am thinking of another solution :
Create interior like at step 6, then
3) (skip this step)
4) use a basic cube
5) build the recess shape using the door shape and an inverted cylinder. The cylinder will be tilted a little to fit against the sloping outside.

I might generate less polygons than steps 3 / 4 of my previous list.

3DCstepsB.jpg (12 Kb, 198 downloads)

I look forward to seeing your results/conclusions. Keep up the good work.

I didn't quite use the above steps.

After producing a lot of garbage, I started with the exterior half.

Then I carved this body part using mainly : "divide", "set position" for the points created by division, add edges, trim.
I added the rounded shapes for the doors.

Next steps :
• Doors
• Doors Animation
• Mirror operation for complete body part
• Add interior texture
• Adjust texture
• Add body parts to make almost complete car
• Add driver cab (add front of the car, create cab interior)

Apercu01.jpg (13 Kb, 180 downloads)