Hi Railfan,
Thank you! I'm working on a few others as well.
So, when you view the model in 3D, what rotation angles do you use to orient it correctly in Simutrans?
I'm using SketchUp, so I build my models in 1 file, making all my edits there, open up the template mentioned in this post:
http://forum.simutrans.com/index.php?topic=1849.msg42606#msg42606This 'template' file has the angle set up so model is at the correct angle in relation to the model. I then just rotate the model/object to create the 2, 4 or 8 views, instead of the camera. If you download/use the template, I recommend the first thing you do is to "Add a scene". This makes a snapshot of the cameras position so if you change it accidentally or intentionally, you can jump back to that view. (by the way, it is nearly impossible to set the camera angle by hand). Once you add the new scene, and before you start copying in your models, save the template with the added scene and make a backup too.
Some people surely render their models with a different application (sketchup doesn't truly render). However, sketchup does a decent job of a low quality render, so you can just export what you are looking at to a PNG. I currently just use the pseudo-render Sketchup makes and edit it with a pixel editor from there.
If you want more pointers on SketchUp, let me know. There are 1 or 2 free application that will make nice renders also. And I can point you to a free pixel editor for Mac OS if you want.
If you plan on using blender, someone else will have to step in here because I don't use blender (I've tried but to me it is not nearly as intuitive as sketchup).
And, when we measure the size of a model in pixels, how do we do that? Is the measurement taken directly across the image (on the x/y axes), or along the length of the model itself in the perspective view?
I'm not sure what your question is. In the 3D world, nothing is measured in pixels because 'pixel' is a screen resolution unit. A 3D model is independent of that measurement, except for how it is displayed on your screen. When you export a flat (2D) image (or render it), the output will have a size in pixels that you can further manipulate.
With the exported (2D) flat graphic, I typically use a template to set sizes and alignments of vehicles or buildings. There are templates that should work for any* pak128 here:
http://graphics.simutrans.com/thumbnails.php?album=9I usually take the template and use that as my base layer, paste in the pngs I created from SketchUp and then align and adjust the length manually to match the template.
How is the accompanying .dat file laid out, and where is the program that takes the .png and .dat files and creates our pak files?
I would start by looking at the wiki:
http://en.wiki.simutrans.com/index.php/Creating_addons
This will give you the basics. I would find an existing .dat file that is similar to what you want to create and edit it to meet your needs. There should also be a number of forum posts on this topic.
And while I'm here, attached is the set of freight vehicles I've built so far (models anyway).