Modelling Tracked Vehicles

[Kydoimos 915]

Hiya all,

 

 

Now, I know this has been covered a lot, especially the subject of caterpillar tracks, however, I've trawled the internet and can't find background information on the process of creating tracked vehicles - my apologies if I've missed something!. Basically, I'm wondering how caterpillar tracks work in Arma 3. I've studied the samples and the models released in Arma 2 ​, but I'm a little puzzled. Somebody said in a post somewhere that the tracks don't physically move at all, and it's something to do with a texture swap (?). So, utterly confused now. I can't see how the track belts on the samples move without texture distortions / stretching? As well, the fact that the majority of the detail on tank tracks is conveyed through normal map seems to suggest something deeper is going on? Or maybe it's just a bit of poly-saving :)

 

Thanks in advance - I feel like the above is a bit of a silly question - but vehicle modelling is very new to me and I fancied a stab at it (believe it or not, I am ​starting small - SUGV small - and I'm not modelling a tank!).

 

Cheers, guys!

[da12thMonkey 1943]

Yeah, the tracks model doesn't really move at all apart from the suspension/damper deformation when driving over uneven terrain.

 

IIRC the visual effect of track movement is actually the UV coordinates of the track selection, moving in UV space along the V axis. So that the texture and materials mapped to the faces translate across the surface of the model as the vehicle's engine rpm changes and vehicle moves.

Default (Czech) selection names for the parts of the track that undergo this moving texture are PasOffsetL/PasOffsetP, but it is ultimately defined by the selectionLeftOffset= and selectionRightOffset= parameters in the config.

 

Tracks are UV mapped across several UV tiles that have a tile-able track texture. So long as the start/end seam of the UVs line up with where the texture repeats, they should appear as a continuous belt and not split when the whole "texture animation" thing runs. Best way is to look at how they're UV mapped in those sample models.

[Delta Hawk 1829]

Is there anyway you can apply the same animation for tracks to a piece of rope to make it look like it's moving?

[Kydoimos 915]

 

#2

Yeah, the tracks model doesn't really move at all apart from the suspension/damper deformation when driving over uneven terrain.

 

IIRC the visual effect of track movement is actually the UV coordinates of the track selection, moving in UV space along the V axis. So that the texture and materials mapped to the faces translate across the surface of the model as the vehicle's engine rpm changes and vehicle moves.

Default (Czech) selection names for the parts of the track that undergo this moving texture are PasOffsetL/PasOffsetP, but it is ultimately defined by the selectionLeftOffset= and selectionRightOffset= parameters in the config.

 

Tracks are UV mapped across several UV tiles that have a tile-able track texture. So long as the start/end seam of the UVs line up with where the texture repeats, they should appear as a continuous belt and not split when the whole "texture animation" thing runs. Best way is to look at how they're UV mapped in those sample models.

 

 

Genius! Thanks, mate - lol, saves me a lot of modelling work on the tracks :P

[da12thMonkey 1943]

Is there anyway you can apply the same animation for tracks to a piece of rope to make it look like it's moving?

 

No idea mate. So far as I know it's part of the legacy vehicle simulation rather than a kind of animation source. Like the rotor static/blur switching for helicopters is selection+config based rather than model.cfg animation. But maybe there's other texture animation stuff like for the ocean surface and the weird shader on some of the VR units.

 

Unrelated, but I think the track "simulation" works on 'Car' type vehicle now too, not just 'Tank' types like it did in the past. So we could do half-tracks and stuff with it now. I seem to remember the SFP mod's BV-206 is configured as a car and has moving tracks in Arma 3 at least.

[x3kj 1247]

One thing to keep in mind for such tracks - you can not influence the speed at which the texture is moving in any precise way. There is a trackspeed token in the config, but if it's not an integer value (say 0.7) the texture will move normally until 0.7 and skip the remaining 0.3.  values like 1, 2, 3 are ok, but most of the time you would need it to be slower than 1.0

So what you have to do is trial&error how many track segments you need on your texture aproximately to achieve the track texture rotation speed you need for your vehicle.

 

 

PasOffsetL/PasOffsetP, but it is ultimately defined by the selectionLeftOffset= and selectionRightOffset= parameters in the config.

i tried custom selectionXOffset names (with all the other stuff that is required for it, like model.cfg sections etc), but they didn't work for me. Only PasOffsetX worked.

[El Tyranos 1263]

Unrelated, but I think the track "simulation" works on 'Car' type vehicle now too, not just 'Tank' types like it did in the past. So we could do half-tracks and stuff with it now. I seem to remember the SFP mod's BV-206 is configured as a car and has moving tracks in Arma 3 at least.

 

Hi ! 

 

Working on IF44 half tracks at the moment, carX simulation, pasoffsets exist and are defined in config.cpp too, they move in tankX simulation but don't move with carX. Do you have any further info on this ? Any trick ?

[da12thMonkey 1943]

Hi ! 

 

Working on IF44 half tracks at the moment, carX simulation, pasoffsets exist and are defined in config.cpp too, they move in tankX simulation but don't move with carX. Do you have any further info on this ? Any trick ?

 

I'm afraid not really, no :/

Only going from what I can see from the SFP Mod's BV-206 which looks like it has tracks working in this manner on a non-tank/tankX vehicle.

 

From the config viewer it has car simulation rather than carX. But selectionXXXOffset defined further up

http://i.imgur.com/LLrK45Q.jpg

No idea what else might be involved like having it defined in sections[] array of the model.cfg or anything else. I'd guess granQ would be the one to ask how the model is actually doing this.

[h4wek 41]

Is anybody try to make tracks in 3d not this texture animation, for other not fast vehicles like shovel this texture anim is too bad looking, so if more bones will be possibile or animation "by path" this could be possibile to do i already make few  samples but loop animation not work well with synchronise of chain elements. Other method like combine animations GIVE SPECTACULAR EFFECT BUT need more bones than 254 when elements of track is for example 33 and every of them take about 9 bones for make whole cycle to move - other problem is looping of this huge animation it work only on clamp now.

https://youtu.be/1qNUQ_Hb0rc