I learnt to use Blender from
this tutorial. There are many sections there that you can ignore entirely for the purposes of Simutrans graphics creation, including anything to do with nodes, particle effects, the game engine, animation, soft bodies, bump mapping, normal mapping and more or less everything in the "advanced" category.
The best thing to do is to download some of the existing .blend files from one of the two repositories (
here and
here) and modify it (e.g. to create a very similar but slightly different vehicle, or a different livery for the same vehicle; the different liveries are only used in Simutrans-Experimental, however).
For exporting the graphics from Blender, you will need to use
this Blender script (there are multiple tutorials on how to install a Blender script: it is very simple).
To use the new, easier workflow, make sure that "output" under render options is set to RGBA rather than RGB (so that Blender automatically adds the transparent background so that you don't have to do it separately); most of the older .blend files have "output" set to RGB, which will produce black backgrounds.
For road vehicles, you need to set the "Rendering views for Simutrans" Blender plugin to "Render 8 views normal alignment". For any other type of vehicles, including trams, rail vehicles, water vehicles and aircraft, you will need to set "Rendering views for Simutrans" to "Render 8 views vehicle alignment". For buildings, signs, signals, stations and stops, you will need to set it to "Render 4 views normal alignment". You can ignore the "make masks" button on that plugin: it is designed for a different pakset's workflow.
Once you have the graphics (8 .png files per vehicle, one for each alignment as will be produced automatically from the Simutrans render plugin), you need to create the .dat file. The .dat file is a text file used to specify the vehicle's data, such as its name, introduction date, capacity, power, graphics and so on. Again, the easiest thing to do is to adapt an existing .dat file. Note that there are some parameters in .dat files that are only relevant to Simutrans-Experimental.
Once you have the .dat and .png files, you will need to compile these into .pak files using a program called makoebj. There is a separate makeobj for Simutrans-Experimental and for the normal version of Simutrans (Simutrans-Standard). .pak files compiled for Simutrans-Experimental cannot be used with Simutrans-Standard, and .pak files for Simutrans-Standard will lack the data necessary for the Simutrans-Experimental specific features. You can download versions of makeobj for both Standard and Experimental from links on these forums.
Edit: For road vehicles, you will need to specify offsets in the .dat files. Do this just by copying the following code, and replacing the name of the graphics in this instance ("daimler-wagonette") with the name of the graphics in question:
EmptyImage[E]=./images/daimler-wagonette_E.0.0,-33,14
EmptyImage[SE]=./images/daimler-wagonette_SE.0.0,-13,0
EmptyImage[S]=./images/daimler-wagonette_S.0.0,0,0
EmptyImage[SW]=./images/daimler-wagonette_SW.0.0,-8,10
EmptyImage[W]=./images/daimler-wagonette_W.0.0,4,5
EmptyImage[NW]=./images/daimler-wagonette_NW.0.0,12,10
EmptyImage[N]=./images/daimler-wagonette_N.0.0,0,33
EmptyImage[NE]=./images/daimler-wagonette_NE.0.0,0,24
For Simutrans-Experimental, if you want to specify liveries, a slight change in the format is required, as in this example:
liverytype[0]=General-early
liverytype[1]=General
EmptyImage[E][0]=./images/lgoc-x-type-double-general-early_E.0.0,-33,14
EmptyImage[SE][0]=./images/lgoc-x-type-double-general-early_SE.0.0,-13,0
EmptyImage[S][0]=./images/lgoc-x-type-double-general-early_S.0.0,0,0
EmptyImage[SW][0]=./images/lgoc-x-type-double-general-early_SW.0.0,-8,10
EmptyImage[W][0]=./images/lgoc-x-type-double-general-early_W.0.0,4,5
EmptyImage[NW][0]=./images/lgoc-x-type-double-general-early_NW.0.0,12,10
EmptyImage[N][0]=./images/lgoc-x-type-double-general-early_N.0.0,0,33
EmptyImage[NE][0]=./images/lgoc-x-type-double-general-early_NE.0.0,0,24
FreightImage[E][0]=./images/lgoc-x-type-double-general-early-loaded_E.0.0,-33,14
FreightImage[SE][0]=./images/lgoc-x-type-double-general-early-loaded_SE.0.0,-13,0
FreightImage[S][0]=./images/lgoc-x-type-double-general-early-loaded_S.0.0,4,0
FreightImage[SW][0]=./images/lgoc-x-type-double-general-early-loaded_SW.0.0,-8,10
FreightImage[W][0]=./images/lgoc-x-type-double-general-early-loaded_W.0.0,4,5
FreightImage[NW][0]=./images/lgoc-x-type-double-general-early-loaded_NW.0.0,12,10
FreightImage[N][0]=./images/lgoc-x-type-double-general-early-loaded_N.0.0,0,33
FreightImage[NE][0]=./images/lgoc-x-type-double-general-early-loaded_NE.0.0,0,24
EmptyImage[E][1]=./images/lgoc-x-type-double_E.0.0,-33,14
EmptyImage[SE][1]=./images/lgoc-x-type-double_SE.0.0,-13,0
EmptyImage[S][1]=./images/lgoc-x-type-double_S.0.0,0,0
EmptyImage[SW][1]=./images/lgoc-x-type-double_SW.0.0,-8,10
EmptyImage[W][1]=./images/lgoc-x-type-double_W.0.0,4,5
EmptyImage[NW][1]=./images/lgoc-x-type-double_NW.0.0,12,10
EmptyImage[N][1]=./images/lgoc-x-type-double_N.0.0,0,33
EmptyImage[NE][1]=./images/lgoc-x-type-double_NE.0.0,0,24
FreightImage[E][1]=./images/lgoc-x-type-double-loaded_E.0.0,-33,14
FreightImage[SE][1]=./images/lgoc-x-type-double-loaded_SE.0.0,-13,0
FreightImage[S][1]=./images/lgoc-x-type-double-loaded_S.0.0,4,0
FreightImage[SW][1]=./images/lgoc-x-type-double-loaded_SW.0.0,-8,10
FreightImage[W][1]=./images/lgoc-x-type-double-loaded_W.0.0,4,5
FreightImage[NW][1]=./images/lgoc-x-type-double-loaded_NW.0.0,12,10
FreightImage[N][1]=./images/lgoc-x-type-double-loaded_N.0.0,0,33
FreightImage[NE][1]=./images/lgoc-x-type-double-loaded_NE.0.0,0,24
This also gives an example of the loaded and empty graphics which are useful to have for old open top 'buses where it is possible to see whether there are people on board or not. This system is also useful for lorries that are not entirely enclosed so that it is possible to see the load, if there is one.
Just to be clear, the "EmptyImage" and "FreightImage" system (empty and full graphics) can be used both in Experimental and Standard, whereas the liveries (the zero and one, etc. in square brackets after FreightImage or EmptyImage can be used only in Experimental.
Because the pakset is open source (under the Artistic Licence 1.0), you may only modify and distribute existing objects and .blend files (and your objects can only be included in a release of the pakset) if and in so far as the new objects/graphics/.blend files that you produce are also made available under the Artistic Licence 1.0.
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Road vehicles are indeed in the process of being rescaled. If you want to work on 'buses, therefore, I recommend that you start by using one of the new .blend files in the
relevant directory of my repository: look for .blend files with a modification date of December 2016 or newer. These will already be set up for rendering with the new system and be in the correct scale.
In order to calibrate the scale accurately, you can import
this 15 meter ruler into Blender. In Pak128.Britain, we use a slightly odd scaling system, in that the width and height are 1.25 times the scale of the length. Also, any vehicle over 15 meters in length uses a special logarithmic scaling system, as a linear scaling system would result in large ships and aircraft being too big to fit in the largest allowed size of graphics. However, rail and road vehicles are never this long, so if you are concentrating on those, you can ignore this complexity.
All of the road vehicle graphics except those that I am rescaling now (the work is in progress, so more will be re-scaled the further in the future from this post that one goes) will be to the wrong scale. The rail vehicles should mostly be to the correct scale, except for earlier (pre-1960s) wagons, many of which are too large (I have not got around to re-scaling those yet). The trams, aircraft and boats should all now be to the correct scale.
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I hope that this is helpful. I am posting all of this here because the
official guide is now rather out of date, but you might find that it contains some useful information not in this post. If there is any conflict between this post and the official guide, however, follow this post, as it is more up to date.
Do let us know if you have any queries or get stuck, and we will be glad to help you.