Experimental Trailers in Parts Selector 1.02

TRAILERS IN PARTS SELECTOR (+ CUSTOM LOADS)


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This mod is my entry for the most recent MFD+BeamNG Modding Challenge: https://www.beamng.com/threads/modding-for-dummies-beamng-modding-challenge-trailers.80952/
I've had the idea to make this for a long time actually, but never bothered doing it because it's so much work (turned out to be way more than I thought too). When I heard about the challenge, I didn't instatntly think of joining. Ultimately though, I decided that I'll need some stuff in this mod later for some other mods I'm making anyway, so I thought, why not do it now after all. So here we are, not hoping for a win, but participating was fun and this is all that matters.

Here's a quick overview of what you can do with this mod, separated into a few sections to make the description more tidy.

THE TRAILERS​

This mod adds all of the vanilla trailers to the parts selectors of cars. It should work on most vanilla cars that have tow hitches, as well as many mods. It might not work properly (or at all) on some mods, it all depends how the mod author set up the tow hitch. There is nothing I can do if my mod doesn't support a certain mod vehicle.

Where should you look for the trailers? It's quite easy. Tow hitches in vanilla cars have an unused slot, which used to be for a vanilla trailer for the D-Series, which was removed years ago. But the slot stayed, and got carried over to most vanilla vehicles. Just open the tow hitch slot and you will find this:


All vanilla trailers are supported by the mod: Small and large utility trailers, small flatbed trailer, travel trailer and the giant flail (which is not a trailer, so it doesn't have some of the features metioned below related to the suspension or loads). You can select the one you want, and configure it.


Speaking of configuration, all the parts selectable on the vanilla trailers are also selectable on these ones. So you can add the silver skins to the utility trailers, stripes to the caravan, license plates, remove the tailgates or fenders, etc. There are some extras though, and I'll explain them now.

Firstly, for each trailer you can select how it attaches to the car:


"Beam attachment" is basically how you attach any part to the car, like doors, headlights, etc. It will be attached already on spawn, can only be detached by breaking off, and can't be reattached later unless you respawn the whole car. With this attachment, the trailer legs will retrace automatically and can't be extended back.
"Coupler attachment" is how you normally attach a trailer. It won't be attached on spawn, you need to do it manually like with vanilla trailers, but you can also detach and reattach it later whenever you want. Note that unlike in vanilla trailers, you will have to manually retrace the trailer legs using the triggers on them, and you can extend them later when you detach the trailer.

Secondly, you can select whether the camera is zoomed out when the trailer is attached (it is by default):


Lastly, I know a lot of people (including myself) don't like vehicle triggers. So by default, tailgates of the trailers don't have them, and they don't have any key bindings to them either, thus they can't be opened. But for each trailer, you can manually change the tailgate to one that has triggers so you can open it:



Aside from these extras, there are also some changes in the slots system of each trailer. The caravan has many of its own specific changes. It has been separated into individual removable components:


All of them can be removed, some can be replaced with other ones:

• You can change the normal propane tanks to experimental explosive ones, BUT BETTER DON'T DO IT. They are a failed experiment that I left in the mod just for fun. 99.9% of the time they just cause an instability when you try to node grab them, 0.1% of the time they completely obliterate everything lol. They create a MASSIVE fireball when you use "explode" or "break" in the "fun stuff" in radial menu. The temperature gets so high that it literally MELTS the car's engine. So... Don't use them for normal driving/crashing.
• You can replace the interior with cargo space and put loads in it, more info about that later. Note that it doesn't support load straps, so everything will bounce around inside.

There are also changes in the suspension of every trailer. Basically, due to the way tow hitches are positioned in vanilla vehicles, the normal wheels system didn't work on the trailers. So I made custom asymmetrical wheels for every trailer:


All the trailers aside from the caravan use 4-lug wheel hubs. For these hubs, I made 9 selectable steel wheels for each, that come in 4 different sizes and various colors, and each of them has 3 selectable tire types on average. The caravan uses 5-lug wheel hubs, where I made 16 selectable steel wheels for each side, that have 5 different sizes and various colors and designs, and each has 4 selectable tire types on average. Only steel wheels are supported, because there are so many wheels in the game I couldn't port all of them, and the rest don't even make sense on the trailers. You still have some radial, sport and whitewall tires for some of them even though they make no sense.

Each wheel and tire can be changed or removed separately, for some trailers also each brake. They can be adjusted in the Tuning tab, and each tire has separately tunable pressure:



Another thing that is different in my trailers than in vanilla ones, is that they have more selectable loads. Let's talk about them in this next section.

THE LOADS​

Each trailer in this mod, including the caravan when you replace the interior with cargo space, uses the same common loads selection. Even if the load doesn't physically fit, you can still try to put it inside because why not. There are many loads to select, so I'll describe each one individually here:

1. 4 Crawler Wheels (139kg)
   
   4 wheels from the Crawler Hopper, strapped to the trailer together. When the strap breaks, they all become loose.
   
   
2. 55 Gallon Steel Barrell (18kg)
   
   A single loose barrell that can hold 55 gallons of a liquid you select (by default it's oil). The liquid adds weight to the barrel based on its density. I added 34 selectable liquids and listed the weight of each of them, some of them are crazy and aren't really liquids lol:
   
   The heaviest ones are so heavy that you can't lift them on normal gravity. (Some you can't lift on ANY gravity!) The infinite mass one is actually so heavy that it instantly disappears and I'm not sure why lol.
   
   
3. Adjustable Metal Box
   
   Unstrapped adjustable metal box prop. Comes with 2 selectable variants: with and without decals. Similarly to the vanilla prop equivalent, you can fully adjust it in the Tuning tab:
   
   
   
4. Hay Bale Square (420kg)
   
   The vanilla hay bale square, attached with 2 straps that can break independently.
   
   
5. Long Wooden Planks (2100kg)
   
   The vanilla load, now available on every trailer in the mod.
   
   
6. Rocks
   
   The vanilla rock props, unstrapped, with all the selectable variants you have in the game (except for the triple one which doesn't fit in any trailer):
   
   
   
7. Short Wooden Planks (1400kg)
   
   Like the long planks, but short.
   
   
8. Single Crawler Wheel (35kg)
   
   Like the 4 crawler wheels, except there's just 1 of them, and it's not strapped to the trailer.
   
9. TastiCola Crate (500kg)
   
   A single TastiCola crate from the T-Series trailer ported here. Attached with 3 straps, and placed on a pallet that can also fall off the trailer independently.
   
10. Tire Stack (130kg Total)
    
    Unstrapped tire stack that is not interconnected and instantly falls over, separating into 9 individual tires. You can remove each tire independently, as well as adjust the pressure of each one (boundaries are pretty low because the tires are not attached to wheels so they would freak out when you tried to add more pressure):
    
    This load is taken from a mod I made some time ago:
    https://www.beamng.com/threads/tire-stack-revamped.77480/
    
11. Unstrapped Mattress (59kg)
    
    The mattress.
    
12. Unstrapped Mattress Stack (177kg)
    
    The mattress, except there are 3 of them.
    
13. Wooden Crate (Adjustable Mass)
    
    Like the one in the Pigeon bed. I made sure it doesn't explode.
    
    

So this is all about the loads. But there's one more thing to this mod that isn't related to tow hitches:

GAVRIL T-SERIES TRAILERS SUPPORT
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The mod also supports the Gavril T-Series with its own trailers! Not only does it let you add them yourself, but it also gives you pre-made configurations with attached trailers ready to go!

The TastiCola configs come with a new skin made by my friend Felipe, who also made the Dubai Police SBR4 skin for my other mod.

But if you want to add a trailer yourself to a config that doesn't have one, I'll tell you how. It's simple, you just have to change fifth wheel to my custom version:


By default, it will spawn with the dry van trailer, but you can change it to the flatbed or the tanker if you wish. The fifth wheel also gives you the same options as the trailers for cars:


I'll go over what options each trailer gives to you now quickly:

• Every trailer gives you an ABS option like the vanilla ones, as well as an option to choose how the trailer legs are controlled:
  
  Note that automatically retraced you can't extend back, while trigger-controlled you have to control each time you attach and detach the trailer, including on each spawn and reset.
  
• The dry van trailer in the mod gives you way more options for parts to remove parts than the vanilla one, but of course old options like skins and stuff still work:
  
  
  All of this because I wanted a removable underride guard lol.
  It has some more options for the doors too. I know many people don't like triggers, so by default they are off, and the doors can be only opened with the key binding that is in the mod by default:
  
  
  But you can add the triggers back if you want:
  
  There's one more thing, about the dryvan loads. The mod includes the vanilla TastiCola load, but combined with the whole vehicle and trailer, this might be too laggy for some people. So I also added unbreakable versions that don't lag:
  
  
• The flatbed trailer has the same options as the vanilla one, + an option to remove the rear frame and underride guard:
  
  
• The tanker trailer includes an option to remove the ladder, other than that it's identical to the vanilla one:
  
  
  Except it also gives you more options for the loads:
  
  Similarly to the barrel, the weight depends on the density. The liquid iron is the heaviest and instantly collapses the trailer on normal gravity (on moon gravity you do massive wheelies with it lol). Titanium is the second heaviest, you can (barely) transport it on normal gravity.

So yeah, it's a pretty big mod... Obviously, there are some issues that I know of:

• It might not work properly or at all for some mods
• Might not support T-Series mods properly or at all
• Caravan might lag the parts selector slightly due to having many selectable parts
• Slots are not in order sometimes but I can't fix it
• Cars with modern ESC drive weird with the trailers, will be fixed by next major update of the game (one of the game devs already fixed it on his end)
• Idk what else but I probably missed something

Credits: TastiCola skin by Felipe Maciel, pretty much everything by BeamNG adjusted by me to fit the mod, some stuff only by me

That's all for the mod, enjoy! Below some info for the contest.

Spoiler: For the contest judges - should help judge the mod

First and most importantly, here's proof of permission for the TastiCola skin:

This is the only thing in the mod that isn't made by either me or the BeamNG devs.

I think my mod passes all the criteria in the contest more or less. It's original and trailer-themed, all the models are from vanilla game so they are good I guess...

Jbeam is mostly repurposed from vanilla trailers and props, with little changes to some values in some cases and A LOT of changes to the slots, which I'll get to later. The only scratch made Jbeam is the pallet under the TastiCola crate load, and I guess the tire stack is modified enough to be called my Jbeam. Weight of everything I tried to get as accurate as possble, liquids weight calculated based on density, etc. As for the console, I tried to avoid any possible errors, as I always do, I might have missed some warnings but generally the mod should be clean, you can check that. It just gives an unusual amount of the blue messages, because a lot of stuff is in the common folder in various files, and also I used a lot of optional stuff that gets loaded only in some cases. Example of what it looks like for me usually:


There's an issue you might have noticed, that parts don't appear in order in the slots system. I believe it to be a game bug related to the tow hitch because it doesn't happen for the semi, so I don't think I could fix it.

Now I think I have to explain some stuff that could confuse you in the mod's files (or did confuse you already in the desciption), so we'll browse through that quickly.

To avoid duplicates, some of the trailers share Jbeam-only parts that don't have flexbodies. All trailers share a generic camera modifier taken from the H-Series cargobox Jbeam, that zooms out the camera when the trailer is equipped. Boxutility trailers share the wheeldata, skins, and the attachment part. That part does a bunch of stuff: it defines the tow hitch node either with or without coupler, optional feet controller, optional triggers, an optional beam that connects the defined node to the car's tow hitch (which has the same name for every car so it always works, even when the beam is zero length thanks to precompression that somehow rounds it up to some small value bigger than 0), and either hydros or precompressed beams in place of them for the feet.

The skin is the same as in the vanilla boxutility trailers (it's already in the common folder), except the word "skin" is changed to "skin_boxutility" and "globalSkin" to "skinName" so it can be used from a slot independent from the car's paint design and have no effect on it. Similarly it's done for the dry van trailer. Boxutility trailers use the vanilla materials from the common folder, but the flexbodies are all renamed to avoid overriding the vanilla trailers. Similarly it's done for some loads that use common materials. Other trailers and loads have renamed both flexbodies and materials, and point to copied textures in different folders to make them future-proof. Except most of them use either van or TSFB materials for lights, which I kept unchanged, I was afraid to mess something up there.

Now for the reason why I had to make asymmetrical wheels. It's actually a simple answer. Vanilla cars have tow hitches positioned using nodeOffset, which is normally used for wheels. If you have 2 of these, the second will override the first. Which meant that on cars with different length, the wheels would appear in different places, being relative to the center of the car instead of the tow hitch. The solution was to use nodeMove instead of nodeOffset, but NodeMove is not symmetrical, so one of the wheels would be offset either to the left or to the right. So now you can see that the obvious solution was to separate the wheels and use a separate nodeMove for each.

The asymmetrical wheels system uses separate spindles for the left and right wheel, to make sure they are loaded independently and don't affect each other.

Each trailer, each part and each load in the common folder (if I didn't forget anything) had all their nodes, slots, breakgroups, deformgroups, rails, etc. renamed to avoid all possible conflicts with mod cars that someone will use the mod on, so the Jbeam files might look like a mess. But you might notice some weird things at the bottom, I'll explain. There's a pressureWheels section that cancels out brake properties, this is for compatibility with mods that don't use spindles properly and would cause the trailer to use the car's brake properties. Another thing is a temporary fix for a bug that is fixed properly for the next major update but still exists now, you can ask Diamondback about it.

Now for the T-Series part... It's even more messy, except most nodes aren't renamed because they already didn't conflict with anything and aren't in the common folder.

Each trailer has 2 versions of its main slot: for long and short frame versions of T-Series. The only difference in them is the nodeMove that moves the trailer body to the proper position depending on the fifth wheel position. I used nodeMove here so I don't have to make asymmetrical stuff again, nodeOffset was used everywhere else. Camera edit part is also different for each frame length.

I copied the brake property remover to the custom fifth wheels to make the trailer ABS independent from the truck one. Since all trailers share the same glowmaps, I put them here too (only the parts that aren't currently in the T-Series main glowmap). Coupler node is removed from fifth wheels and re-added on the part that determines the attachment type, this is a core slot so it won't cause any issues. Of course it's different for long and short frame.

The vanilla trailers all use a bogie from the common folder, but it conflicts with the T-Series node names so I made a custom one with some changed naming stuff instead and all my trailers use it. It still has slots for vanilla parts in the common folder. My trailers also use my own version of vanilla trailer feet, and mudflaps with renamed nodes. But they use a vanilla common bogie and spare tire holder without changes.

The dryvan "no lag loads" are old vanilla parts that got removed from the game but I had a backup so I re-added them.

My tanker has some optional beams in its Jbeam file, they are for the load, I move them there or else I would have tons of duplicates of the same beams section in one massive loads file. I also made it so the tanker load is loaded directly after the tanker itself, and included some nodes setup at the end of the tanker's nodes section, to shorten the loads file even more. The tanker nodes use this setup, and if it's empty then the next part in order overrides the setup, it's a core slot so it always works.

This is probably all of the confusing stuff, I hope I have cleared it up a bit lol. Maybe it will help you judge the mod.