Hatchback rally car

[aljowen]

Guys, im actually quite proud of what i have done so far

Please feel free to give suggestions on how to improve my model. Am i right in saying that triangles are bad, squares are good? If that is so then i will work on getting rid of some triangles tomorrow.

Its midnight here, so i guess its time to sleep

Here is a screenie. You can see work starting on the interior and the bonnet done to some degree, may edit the bonnet later to make it fit the car's style better.

I am already doing much better than anything i could have created in sketchup and i am getting used to using the software. bye for today

EDIT: Just notice i need to make the passenger area deeper

Resolved size issues, Right now i really should sleep, must resist working on

Updated images and added a wireframe for those interested

[masfilip]

Great! It´s good to see that people makes good model in Blender instead of stealing other works or making not good cars in Sketchup

[aljowen]

Great! It´s good to see that people makes good model in Blender instead of stealing other works or making not good cars in Sketchup

I never stole anything of the warehouse!
But thanks for saying its a good model

[aljowen]

Another picture of an update, fixed any back faces too.

So far there are 3 separate objects(the bonnet,interior,chairs)

[aljowen]

The mesh is getting a bit messier now, trying to get the door area to a reasonable width while providing leg room and space for the wheels to turn. I may end up reducing the leg room for the sake of the mesh looking nicer. Also yes the seats are floating but i doubt you will notice that while using the vehicle in ror.

[thabigdipper]

Always awesome to see someone making something original keep up the good work

[Gouranga]

If this is your 1st serious non-sketchup model, I must say you've done pretty good job. It's kind of funny how you started with the interior, I think it's unusual, but nothing wrong about that.
About the N/B, I've done some basic changes that apply to every lightweight car, though there are other important things to do:

1. globals, minimass, nodes
   you're gonna need to set global weight to 0, minimass to something small like 0.5-2.0 and add "l ?" to each node's options, where ? is node mass in kg. Set higher mass to suspension components so you can make it strong, medium to lower body parts and make roof and body panels light.
2. engine
   I've changed the max rpm, torque and gear ratios so it's usable. Torque may be still too high. You might want to squeeze in sixth gear, preferably before the 1st and lower diff ratio.
3. engoption
   Inertia is much lower to improve acceleration and ignition time. Reduced clutch force to fit lower torque. Reduced shifting time.
4. brakes
   Much lower to fit lower engine and wheels inertia and also overall vehicle weight.
5. set_beam_defaults
   You know you'll need to set this separately for different beams, right?
6. wheels
   Way lighter and also softer. Might seem too soft laterally, but you can fix it by switching to meshwheels2. I can provide my rally gravel rims, or maybe older tarmac rims. Scale should be realistic, 15" for the gravel and larger for the tarmac. Both without textures though, I can't make them to work in RoR myself.
7. shocks
   Made them softer. Are they self-leveling on purpose? It's not realistic, you should add sway bars instead.
8. fusedrag
   Added to improve both top speed and acceleration. I didn't know to which nodes I should attach it, so you'll probably need to fix it. See wiki if needed.

Other notes:
Suspension setup is not very realistic, most, if not all recent rally cars use McPherson struts. But I know they are not that simple to make in RoR.
The car is very oversteering, this could be improved with some proper suspension geometry and springing setup.
Wheels seem too large, mine buggy is supposed to have rally gravel tyres and radius of 0.317 should be just right.
What is the wheelbase? It seems too short unless you want to make a car like Mini or Peugeot 205.

[Creak]

Other notes:
Suspension setup is not very realistic, most, if not all recent rally cars use McPherson struts. But I know they are not that simple to make in RoR.

I think modeling a McPherson strut setup is not that hard, maybe have a look at the Chevrolet Express Silvermanblue and I have made. It uses them in the front and is not very complicated, for every side you'll need two slidenodes.

[aljowen]

If this is your 1st serious non-sketchup model, I must say you've done pretty good job. It's kind of funny how you started with the interior, I think it's unusual, but nothing wrong about that.
About the N/B, I've done some basic changes that apply to every lightweight car, though there are other important things to do:

1. globals, minimass, nodes
   you're gonna need to set global weight to 0, minimass to something small like 0.5-2.0 and add "l ?" to each node's options, where ? is node mass in kg. Set higher mass to suspension components so you can make it strong, medium to lower body parts and make roof and body panels light.
2. engine
   I've changed the max rpm, torque and gear ratios so it's usable. Torque may be still too high. You might want to squeeze in sixth gear, preferably before the 1st and lower diff ratio.
3. engoption
   Inertia is much lower to improve acceleration and ignition time. Reduced clutch force to fit lower torque. Reduced shifting time.
4. brakes
   Much lower to fit lower engine and wheels inertia and also overall vehicle weight.
5. set_beam_defaults
   You know you'll need to set this separately for different beams, right?
6. wheels
   Way lighter and also softer. Might seem too soft laterally, but you can fix it by switching to meshwheels2. I can provide my rally gravel rims, or maybe older tarmac rims. Scale should be realistic, 15" for the gravel and larger for the tarmac. Both without textures though, I can't make them to work in RoR myself.
7. shocks
   Made them softer. Are they self-leveling on purpose? It's not realistic, you should add sway bars instead.
8. fusedrag
   Added to improve both top speed and acceleration. I didn't know to which nodes I should attach it, so you'll probably need to fix it. See wiki if needed.

Other notes:
Suspension setup is not very realistic, most, if not all recent rally cars use McPherson struts. But I know they are not that simple to make in RoR.
The car is very oversteering, this could be improved with some proper suspension geometry and springing setup.
Wheels seem too large, mine buggy is supposed to have rally gravel tyres and radius of 0.317 should be just right.
What is the wheelbase? It seems too short unless you want to make a car like Mini or Peugeot 205.

Wow, that has made such a massive improvement to how it drives. Thank you!

Yeah, the car is meant to be that short. If you look at the mesh i am making you will see it only fits two seats in

set_beam_defaults = Yeah i had kinda figured from looking at the .truck file of other vehicles
wheels = the reason i set them so stiff was because the wiki tells you to increase stiffness if they cause the vehicle to shake, and yes i do plan to update them to mesh wheels. I have attempted to make them wheels2 before but they exploded and i had tried quite a few different settings and they were still exploding so i changed them back so i could come back at later date and have another go
New engine = Wow its brilliant, make the car so much nicer to drive. The car is quite a bit of fun while driving around Crete
shocks = made them self leveling to see if i could make the car a bit more stable in corners, couldnt see much difference so i just left it in
Fusedrag = never heard of it, now looking at the wiki to find out more
Double wishbone set up = I looked at ror book at a mcpherson strut because thats what most small vehicles use. Then i saw one in ror and then looked at a double wishbone setup because i understand how they work properly and it looks way easier to make

I will include your name in the cars credits because you have made a very large difference to the overall vehicle

[Gouranga]

I will include your name in the cars credits because you have made a very large difference to the overall vehicle

Oh that's nice I'm glad I could help, it's always nice to see someone doing the hard work and not just asking "how do you make a car?".
If you want to use meshwheels2, use sbd before the mw2 section to reduce beam stiffness like this: set_beam_defaults 750000, 20, 200000, 300000
Springing from 500k to 1M should do. It will also prevent wheel beams form tangling. Damping doesn't make much difference and high value can make the car drift when standing with applied brakes.
You may have read the old mcpherson instructions without slide nodes. With slide nodes, you can make the strut as a beam with 0 stiffness, attach an upper wheel hub node to this beam as a slidenode so it will keep correct camber and then connect this node to top mount with regular shock. This way, if you'd like to make a gravel version, you can even have 2 shocks sliding in series on the strut to simulate dual rate springs. Although I'm not sure if correct damping value could be calculated the same way as the common spring rate. And I've never tried it nor seen it. And progressive springs of shocks2 are easier to use.

BTW try some front toe out and rear toe in

[Creak]

I have added McPherson struts to the front of your car, just in case you need them.

[aljowen]

I think modeling a McPherson strut setup is not that hard, maybe have a look at the Chevrolet Express Silvermanblue and I have made. It uses them in the front and is not very complicated, for every side you'll need two slidenodes.

My point exactly
It uses slide nodes etc, i haven't learnt how to use them yet and i am trying to keep this relatively simple for myself. I will take a look at how slide nodes function and how mcpherson strut can be made with them and perhaps have a go. But i cant promise anything.


EDIT:

Oh wow, your comment was posted while i was writing this one

I shall have a look at it and attempt to work out how it works

---------- Post added at 03:02 PM ---------- Previous post was at 02:51 PM ----------

I have added McPherson struts to the front of your car, just in case you need them.

Its amazing how much difference just changing the type of suspension helps with the amount of grip the car gets, thank you.

I think i am going to add mcpherson struts onto the rear of the vehicle too because they do seem to work much better than double wishbone suspension in this case.

Adding you onto the credits list as well Creak

[aljowen]

I am guessing i did something wrong or missed something?
Cant figure out what though?

Does this require rigidifiers, i cant find any but

[Creak]

With the slidenodes line you have added:
;rear
25, 48, 50
30, 48, 50
27, 49, 51
29, 49, 51
you have set the nodes 25 and 30 to "slide" on the beam between 48 and 50, the same for the other side. The only problem you have is that there is no beam between 48 and 50 and between 49 and 51. Add these two beams and it will work
It maybe was a little bit hard to see because I have made these beams invisible at the front.

[aljowen]

With the slidenodes line you have added:
;rear
25, 48, 50
30, 48, 50
27, 49, 51
29, 49, 51
you have set the nodes 25 and 30 to "slide" on the beam between 48 and 50, the same for the other side. The only problem you have is that there is no beam between 48 and 50 and between 49 and 51. Add these two beams and it will work
It maybe was a little bit hard to see because I have made these beams invisible at the front.

Right, i have fixed it now. Rear suspension has been swapped out now

I think i will work on anti rollbars next

[Gouranga]

In this version I tried to suggest what suspension geometry should look like. There are things like caster and kingpin inclination, tiny negative camber and toe in/out, ackerman... Rear springs and all dampers are slightly softer, though it still oversteers a lot. Front top mounts could be even more in the back and lower. Rear suspension should be more or less mirrored version of the front. Now the steering rods are too short, they should be connected to other nodes than the lower arm, more inside.
Anyway if you want even more realistic suspension, the lower arms shouldn't be connected to the axles. Instead wheel hubs should have the lower part same as the top, i.e. they should be like diamonds with the axle in its center. That way you can keep realistic both geometry and ride height.
BTW nodes 44/ 45 are not necessary, if the beam has 0 stiffness and is attached to the inner axle node or to suggested bottom wheel hub node. Or, you could recycle them for this purpose

[aljowen]

In this version I tried to suggest what suspension geometry should look like. There are things like caster and kingpin inclination, tiny negative camber and toe in/out, ackerman... Rear springs and all dampers are slightly softer, though it still oversteers a lot. Front top mounts could be even more in the back and lower. Rear suspension should be more or less mirrored version of the front. Now the steering rods are too short, they should be connected to other nodes than the lower arm, more inside.
Anyway if you want even more realistic suspension, the lower arms shouldn't be connected to the axles. Instead wheel hubs should have the lower part same as the top, i.e. they should be like diamonds with the axle in its center. That way you can keep realistic both geometry and ride height.
BTW nodes 44/ 45 are not necessary, if the beam has 0 stiffness and is attached to the inner axle node or to suggested bottom wheel hub node. Or, you could recycle them for this purpose

Im not sure i like this one as much, the car under steers a lot more and the steering breaks a lot easier (just by turning in some cases). I also think that the cars turning circle is too wide and that when you try and adjust the hydros to make it turn tighter the steering is even more prone to breaking. Other than those things i didn't really notice any difference i have to say.

Could you explain a little more about what you have changed and why so i can try and understand the plus points a bit better, thanks

[Gouranga]

Yes, it wasn't supposed to be perfect, I did it using pspad and it takes some time. I just wanted to show how real suspension is done in case you aim for maximum realism. Steering would need to be changed like I wrote not to collapse. Understeering is actually what you should aim for, you can tune it quite well with anti-roll bars, springs and toe later.
Now it can't handle very well, these wheels are not stiff enough and ARBs are vital. And it really takes some time consuming fiddling with setup to get optimal handling.
About the geometry. Caster and kingpin incl. causes return to center effect and very important change of camber with steering angle. Lower arm alignment kind of follows strut angle during wheel movement and causes anti-dive effect if the arm isn't horizontal in the beginning. By analogy it works for squat with rear suspension. You can notice how back of a (real) car with trail arms sits lower when you use parking brake on slope.
If you want, I can put more time into it and try to make it better, but I'd feel like I'm trying to take over your project

[aljowen]

Yes, it wasn't supposed to be perfect, I did it using pspad and it takes some time. I just wanted to show how real suspension is done in case you aim for maximum realism. Steering would need to be changed like I wrote not to collapse. Understeering is actually what you should aim for, you can tune it quite well with anti-roll bars, springs and toe later.
Now it can't handle very well, these wheels are not stiff enough and ARBs are vital. And it really takes some time consuming fiddling with setup to get optimal handling.
About the geometry. Caster and kingpin incl. causes return to center effect and very important change of camber with steering angle. Lower arm alignment kind of follows strut angle during wheel movement and causes anti-dive effect if the arm isn't horizontal in the beginning. By analogy it works for squat with rear suspension. You can notice how back of a (real) car with trail arms sits lower when you use parking brake on slope.
If you want, I can put more time into it and try to make it better, but I'd feel like I'm trying to take over your project

Yeah im just going to google some of what you just said

could you possibly explain how i should go about stopping the under steer and how i would go about adding a anti roll bar to a mcpherson strut with camber.

About the realism, i am aiming to create a car that feels quite realistic but it doesn't have to be perfect (realism wise) because if the car isn't any fun to drive, well there wouldn't be much point in making it over a Renault espace for ror.

Yes i would like to make some of the car my self, not that i am ungrateful for the help you have given by sorting out the engine and changing the front suspension

Cant find out what an ARB is (when i Google it, it comes up with blood pressure and drugs. Which i assume you aren't talking about)

[Gouranga]

ARB - anti-roll bar. Generally the more resistant to roll an axle is compared to the other, the more it will slide compared to the other. There are basically 3 things which influence body roll: ARBs, Springs, track width. So for example stiffer front ARB produces understeer. Narrower rear track width also produces very little understeer. Both is used on real cars. It's because the axle that resists roll better is the one that deals with most of the weight transfer. Although IRL this is because adhesion of tyres decrease under more load, it seams to work in RoR either. I guess it's because loaded ror wheels simply deform more.
IMHO car's are most fun if they are stable on straight line in the first place, don't spin out of control too easily, but you can still make them powerslide with proper gas/brakes control.
If you want a hint on how to make ARBs, take a look at this little project of mine. It's the pyramids protruding above the car. The beams connected to wheels have very low stiffness and damping. They determine ARB's stiffness. The other pair holding the single node should be as stiff as possible. And that node should be rather lightweight.
EDIT: here's a link to the whole zip file, without it tha buggy wouldn't work: http://www.rigsofrods.com/threads/79...l=1#post972576