Chariots and carts
Hi ITW fans.
This is the preview of the possibly most original unit of ITW Gold, and probably the most controversial (let’s see the discussion).
It comes from the idea of inserting one aspect that CA forgot when developed RTW, the supplies. It was an original idea of Idibil (CeltiberoIdibil), that was able to convince CeltiberoCaesarAugusto to make a nice model, but that did not work in game. And there began my contribution. The final result can be seen in the following image
and I’m going to tell the story of the genesis of this unit, the problems found and the limitations imposed by the game engine.
This will be a long story, hence I recomend to pass to the final part (possible uses) if you don’t like such kind of stories.
The story of the chariot
When this model came to my hands, I had no idea about how the chariots work in RTW (apart from wheels and horses). Thus I had to investigate and also to ask to the experts that had been working on chariots in other mods (Troy, Zhang Guo...). But our chariot had several original points:
- Two axes: all the chariots in RTW have only one (one only pair of wheels).
- Two sets of horses, but one behind the other, not side-by-side as in other mods.
- One only driver, sitting if possible.
Each one of this original points made me go mad.
1) The axes and other pieces.
The first surprising thing in the 3D models of chariots is that they are not organized. This means that the game has instructions enough to build the chariot from its pieces, and these instructions are in descr_mount.txt. The pieces must have the standard names, if not the game doesn’t recognize them. These pieces are one main body, 2 wheels, 1 pole, 2 scythe blades, and 3 harnesses. In view of that, the additional wheels cannot be named “wheel03” and “wheel04”, but they must be linked to other piece. The scythe blades where reduced to simple “nuts”. Moreover, there is no accessible animation for the chariot, and all the changes had to be visualized directly in game.
This was the less bad solution:
The additional wheels were anchored to the pole (as should be in reality). In this way the wheels are driven wheels, and move when the horses change direction (see the image).
The big problem was to put the coordinates of each piece in descr_mount, as they are not too much “intuitive”, mainly the distance of the horses and the harness height. The problem is that the pole has no fixed length, but it is deformed by the game to adapt it to the distances. In this way models like the one in the image were obtained
where the oval wheels are produced by that deformation. In base of screenshots, rough measurements and lots of failed attempts, I found the appropriate parameters to the horses models used.
2) The #@*ˇ&%#| horses.
In other mods, four horses had been put in one row by doubling the horse model in both sides of the skeleton. In this way:
As I’m rather naďve, I thought: “I will make the same, but one horse in front and other in back, or better one directly on the skeleton and other in front”. In this way:
But when I tried to import an animation the result was:
After searching for the error for some days, I remarked that there was no mistake, but a bad assumption. All the movements of the horse take place in the same vertical plane, but they are rotations of the bones. What does it mean? The animation moves each vertex at the same distance, but also with the same angle, with respect to the assigned bone. The front horse foot starts from a relative position respect to the bone marked with a red arrow in the image.
If the skeleton moves, the position vector moves accordingly, and this generates the funny image (in those days the image was not so funny for me).
This result demonstrated that my idea was wrong and I returned to the old method: paired horses. It seemed to me that this method was difficult... but it worked!
In descr_mount the two normal horses are placed at the same distance in front of the chariot, in both sides of the pole. I put the paired horses just in the centre (fortunately the real horses are not there!!), but at different distances from the chariot. This situation was strange for the game, that put the harnesses accordingly. What I did was to make the harnesses transparent (alpha channel), but to put them directly in the paired horse model.
3) “Taxi” driver.
Finally it was necessary to look for an existent animation of a sitting driver. The only one I think it is the driver of the scorpion cart (BI). But I wanted this only soldier to be present, not the one firing the scorpion. I feared this point, but the game accepts it, just by eliminating the arrows from export_descr_unit. It was also necessary to look for the right coordinates, just to prevent the driver to be “floating” in the air or “trapped” into de chariot.
The only point I didn’t like was that the driver was standing when the chariot was in movement. Yesterday I was able to create a new animation, and now the driver is always sitting.
This unit works perfectly in battle, and this is the aspect when destroyed by the enemy.
Problems without solution (everything is not fine):
a) The chariot animation (hard-coded) only considers one pair of wheels. Hence the only wheels that turn are those in the back. The front ones seem to be pulled.
b) The chariots are configured to move always horizontal, and this cannot be changed (to the best of my knowledge). In planes or smooth slopes this is not a problem, but in high slopes there are strange visual effects. For example:
In a downwards slope, the front wheels don’t touch the ground. In the upwards slopes the front wheels are inside the ground.
c) Formations: as it happens with elephants and chariots, the big size of the unit produces strange and erratic movements. More tests are needed, but it seems to me that there is no solution.
Possible uses of this unit: supply convoy
For sure this unit will give moral bonus, as the eagles or generals. I’d like they could work as defensive screens, but I think it is not possible.
We would like to receive your suggestions about other uses, mainly in campaign. Along this time (the model was finished by the end of November), the team has been discussing several possibilities, but I’m not sure if they can be implemented.
- Generation of economic resources, either directly in money or in commercial bonus. It is doubtful if the presence of a unit can make this, but I will study this point.
- Need to include one convoy in armies outside your own territories (or allied ones). This would serve to simulate the difficulties to get supplies, except sacking. This seems to be even more complicated than the precedent point.
- Reduction in maintenance costs of the units grouped with this convoy. I don’t know if it is possible.
- Increase in movement points of armies with this unit. This would simulate the easiness of the army to march, without worrying about supplies. Again I don’t know if this is possible.:hmmm:
We are waiting for your suggestions.
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. Unless this unit is at the same time an agent, but I don't know any mod where the agents have been modified further than the 3D model/texture or some slight modification of their attributes (enter in settlements when sieged, movement points, etc).:hmmm: 
:tooth:
Originally Posted by Dulce_et_Decorum_Est
