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dpcars
S2 licensed
Quote from srdsprinter :@ DP - Any idea when we could learn more about the Atom-esque Two seater you have generated? It looks awesome too.



The alternate Body for the DP1 is interesting, but not as appealing to me. The 95% cost you mention is interesting, is that mainly if you produced a new mold for the body? I remember that the mold cost was a pretty extreme first cost.


i'll post specs and more pictures soon, probably two-three weeks. but basically it's powered by a 5.7L chevy LS 'crate motor' sitting longitudinally and driving a transaxle. RWD, 400-600hp, 1,600 lbs. target price around $40K for a roller (no engine or gearbox). it'll be sold as a kit or complete roller so if you don't like the LS then pretty much anything would fit in there.

to clarify the 95% thing - what i meant is that dp1 is 95% cheaper than ferrari FXX (i.e. 5% of $2.5M, give or take
dpcars
S2 licensed
Quote from tristancliffe :Inventor is also a paremetric sketch based system. But I find it much easier to make a design, add holes, thread holes, do cross sections, make drawing views and produce realistic views (whilst I'm working on it - using the realview thingy in Solidworks doesn't work for me).

We've still got SW at work, so I'll keep experimenting now and again, and I'm sure if I could get my head around the working method it'd become relatively easy againm but my mind just suits Autodesk's mindset.

Ultiamtely, I tried SW because I'm insanely jealous of your creation.

these programs are just tools, whichever one enables you to be most effective and works with your way of thinking is the right one to use.

creating one's own car is a very frustrating but also a very rewarding process. i don't know much about your background but if you have an interest in doing that i would encourage you to go for it. it'll likely take years (see www.kimini.com - the guy took 10 years to complete his design) but just the learning experience is well worth it. whatever tools you use is secondary.
dpcars
S2 licensed
Quote from tristancliffe :I like so many things Solidworks can do, but I can't get my head around the simple stuff. I'm too indoctrinated into the Autodesk way of doing things - I used to use AutoCad, but now I'm an Inventor person.

I tried Solidworks again today, simply because I read that article and loved what it produced (and I read something in Racecar Engineering the other day too), but my gosh simple things aren't simple to me!

it's a very different way of thinking. you need to think more conceptually in sw, i.e. in terms of solid shapes you create. everything starts with a sketch and the key thing is that a sketch basically defines RELATIONSHIPS and SHAPES rather than 'hard data' - it can all be tweaked at any time and all subsequent steps rebuilt with new data. rather than exact dimensions think 'concentric', 'tangent', 'parallel', 'vertical', etc... dimensions are changeable and secondary.

the real trick to using a parametric system is to think of building objects in terms of parametric blocks that relate to each other. i keep hearing autodesk guys call it 'history' but that is fundamentally wrong. it is not 'history' because you can go back and change it at will and that is the essential difference from 'deterministic' programs. i think of the steps used to create something as a 'structure' of the object.

don't know if that made any sense or not...
dpcars
S2 licensed
Quote from Mikkomattic :Ah, a realism/immersion setup, and a lovely one at that. While struggling with the same issues, I've done pretty much the same you have, with slightly different setup. I hope I can offer some useful advice:

1. Adjust the pitch (up-down viewing angle) to make the horizon on screen match the real world horizon behind the viewscreen. This makes the brain connect better (balance senses and all) as there's less mismatch with what the senses is telling it. You'll probably have to adjust the seating position too if you want to keep that instrument cluster view.

2. The Field of View (FOV) looks like it is yet a bit larger than real life, and that would make things appear smaller than they are to the eye in real life. Lowering this (zooming in, in essense) might give immersive results. You should even be able to do the exact math to calculate this by measuring your real field of view from eye to edges of the screen, in degrees, and then setting LFS to exactly that number. I don't know if it's horizontal or vertical FOV that LFS uses.

Please let me know what you think.

ideally, for a 90 degree FOV your eyes need to be half of screen width (actual width, not diagonal) away from the screen. so for a 40" wide panel like i have, the eyes should be 20" from the screen at 90 deg. that's not quite practical with the present setup (as a background project i'm thinking of how to put something together that makes it work). i'm about 30" away and as a compromise run about an 80 deg FOV which is not perfect but pretty darn good. i like that i have to physically turn my head to look through corners!

with large monitors dropping in price every day there might come a time when i just get a 60" wide panel and all will be good. until then one has to make do

Quote from srdsprinter :The DP1 has been spotlighted in by SolidWorks (the CAD program used in the design of the DP1).

http://files.solidworks.com/ca ... /pdf/random_research1.pdf

Interesting notes there to those who read through the article about what the future of Palatov motorsports might hold! Electric?

the electric stuff is a separate endeavor, i like to think of it as my 'carbon credits' that way i don't feel guilty about wantonly burning up dinosaur juice on the track, i offset it with doing good elsewhere. there are, of course, plans for greener powerplants for the racecars too but that's a ways down the road. some fun things though

it won't be boring, that's for sure
dpcars
S2 licensed
Quote from Hallen :
The tires are interesting. Dennis had a lot of trouble getting any heat into them when driving the prototype. Sure, he wasn't going 10/10ths, but still... It probably has something to do with the very low weight of the car. Finding the right tires will be an interesting challenge.

the main issue is that on the prototype the tires are road-legal R compounds which by definition are made for much heavier road cars. i WAS able to heat them up on a kart track where the turns never stop but on a full-size track there are too many straights also, the prototype only has a stock 180 hp 4-cyl hayabusa motor. my engine builder tells me he should be able to get close to 500hp from the 3.0L version of the V8. good to have a few spare horses just in case the weight comes in a pound or two over target.

lesson learned though - this thing has to run on slicks. i don't anticipate any low-heat problems once i put proper racing tires on it. we'll see.
dpcars
S2 licensed
Quote from Hyperactive :Looking forward to hear more about the dp1, looks like great project, hope it pays off

thanks the payoff is already there in terms of experience and the opportunities that became available because of it. but of course there's much more to do and to learn.

check the site for updates every now and then, there's a lot more coming
dpcars
S2 licensed
Quote from Bob Smith :Well, the usual installation method is coil over dampers, so the dampers should be affected by the motion ratio in the same way as the springs, but that wouldn't affect the overall shape of the graph. I've seen data for bump being set as soft as 3 to 4 times softer than rebound, in certain circumstances.

there are lots of factors that affect suspension setup. generally, stiff rebound helps control body pitch/roll at the expense of mechanical grip. ideally the purpose of the shocks is to keep the force at the tyre/pavement interface as constant as possible, both at high and low frequencies. in practice the shocks also have to control the body motion to limit undesirable geometry changes, unless the spring rate is high enough relative to vehicle weight that the body essentially doesn't move. this is how race cars end up with spring rates that may seem ridiculous in terms of traditional 'natural frequency' approach which is comfort-based rather than performance-based.

other factors are things like unsprung weight and sprung/unsprung ratio, geometry specifics, tyre particulars, ad nauseum.
dpcars
S2 licensed
Quote from Bob Smith :Yeah, we have always assumed dampers are linear in LFS. I know that dampers are never like that on modern cars. At work I've got some dampers tables for a Ferrari and I was surpised just how non-linear they are. I'm due to mail Scawen a bunch of questions, I'll make sure I get something about this on this list. I just pray it doesn't get too big, I don't want to email the man a book now do I.

here's a link to a dyno test result of the dp1 proto shocks - they are ohlins ST-44 (and yes, they're quite soft, but it was a first shot at it).

http://www.dpcars.net/misc/shocks.jpg
re: dp1
dpcars
S2 licensed
Quote from aroX123 :thx

To bad it's not going to be lfs next car
look's like a le mans car.. i want that

if you're interested, for more info on the car you can check out http://www.dpcars.net/dp1

i've been using the VHPA to test various gearing that's available from Hewland (the program works great!). there is an alternative setup that i've uploaded to http://www.dpcars.net/misc/dp1_gear2.set

dp
dpcars
S2 licensed
Quote from Bob Smith :I'm sure Dennis mentioned somethime about axle twist due to inboard brakes on the dp1. Sadly I cannot find in emails/his site where this was mentioned, and I remember the exact figure. I remember it being higher than I thought, over 20 degrees I think (under full braking, that's 1.6gs or so).

the dp1 has unusually long halfshafts due to wide track and long suspension arms, so they tend to act a little like torsion bars

at 1.5g braking the fronts are indeed twisted 20 deg but it's only 54% yield strength. each shaft is seeing 440 lb-ft of torque at that point. like everything in engineering it's a tradeoff - the shafts are loaded but the suspension arms are not so lots of things can be lighter. and since the shafts see the same load under acceleration they already have to be this strong anyway and yes that means they twist under acceleration too, though it's the rears that do most (72%) of the work in that case.

as long as the tyres stay in contact with the pavement it's actually a bit of an anti-lock feature and works quite well in real life. simulating this accurately can be quite a trick of course.
Last edited by dpcars, .
dpcars
S2 licensed
Quote from Mikey :dpcars, Interesting stuff, congrats to the work you've done so far, DP1 looks like an awesome car, and I wish you all the best with its development. Sounds promising that LFS might see it in the future at some point too. Hopefully it will be more successful than RAC (raceabout) (which seems very much unloved online) but one of my favs as its the closest layout to my elise.

Some of the cool stuff in LFS that I love playing around with are the onscreen layovers, these can be accessed in replays too, I don't know if you've seen them heres a quick run down:

F = force views (see what forces are being applied, acceleration cornering)

F9 = tyre view (shows tire/tyre load, tire/tyre temps IMO)

shift-L (I think) = suspension view shows what the suspension is actually doing

These combined with F2 & F3 to speed up slow down the replay view. Have really help me understand vehicle dynamics from in a picture book way. Which has really helped my driving loads.

thanks, i've played a little with the force view but not so much the others yet. definitely need to do that!
dpcars
S2 licensed
i've been playing with my LFS setup and after thinking about it for a while realized i had to sit A LOT closer to the screen... the result is quite amazing actually (there is a slightly more detailed writeup on my site http://www.dpcars.net/etc.htm)




Last edited by dpcars, .
dpcars
S2 licensed
Quote from LFSn00b :When the devs are going to release the skinfile of the new car?

there has been no commitment or promise by the devs to release anything, to my knowledge...

there are some very interesting (and fun! ) things going on but as far as i know an official release of dp1 in lfs remains only a possibility, no more and no less.
dpcars
S2 licensed
Quote from Mister2zx3 :Will the V8 Atom be a 400hp Atom?

yep - see http://www.dpcars.net/atom.htm for the full story on 'project bikini' (just click on page 1 upper right for the beginning). it's taking a lot longer than hoped for but so it goes. i'm awaiting arrival of a wideband O2 sensor to facilitate mapping of the ecu. too bad the rains have started already...

dp
dpcars
S2 licensed
Quote from silentwarrior :Bikes? Why not ? I am a car fan, but, bike represents some nice horse power with low weight, and this could be alot of fun, specially with a mix of cars and bikes on same race, where a car would overtake a bike on speed but not on acelaration.

This would really make the game alot more fun, plus, with this games tradition of realism it would probably the most realistic moto simulator.

Also, this would work good for city driving servers too.

I can only hope to ever ride Fernbay in a bike.


Also, we need more tracks, tracks with less room at the sides, where the action is more packed, and with nice high speed turns instead of the slow to 70km/h turns, those really sux, and is where most ppl dont brake in start, making every race a hope everyone brakes challenge.


Also, Live For Speed is not Live For Cars, bikes are a good part of the motorsport scene, so, why not include them, would be a really nice twist, and would also break the routine of always having 4 wheels.


This is a for fun simulator, not a for learning simulator, so, bikes = more fun.


PS: after seeing the other posters post about the Carver, would love to see something like that in, maybe a normal one and then a GTR one? that, would be fantastic, more fun !

just a perspective: being someone who regularly takes both bikes and cars to the track i can say that riding a bike is a very PHYSICAL experience. that means the body positioning, body weight transfer, the feeling of dragging knee along the pavemet are what it's all about. i would think that this experience would be very diffcult to simulate. none of the arcade bike games even come close. driving a car on the other hand is a 'sitting down' exercise that is pretty well suited to simulation. of course the g forces and 'seat of the pants' feedback are all missing but i've found with a decent ffb steering wheel the experience is quite satisfying. and no, motion simulators don't help - i've tried a bunch, from simple to very fancy, and i've yet to experience one that helps the simulation rather than distracts from it by providing confusing/unrealistic feedback. no feedback is better than bad feedback.

my point? i think that the physics of bikes can be simulated well (although it's a subject complex enough that many of the professional bike race schools don't agree on things as fundamental as how a bike is steered!). but the experience just doesn't lend itself well to simulation, at least not with any controller hardware i've ever seen.
dpcars
S2 licensed
Quote from tristancliffe :CoG Height
Motion ratio of suspension (certainly not 1:1!)
Unsprung Mass (not without a complete stripdown of each corner)
Cd
Cl
Position of aero centres.
Brake torque (you be much better off with bias bar position, master cylinder diameter, wheel cylinder diameter, pad area and Cf, but maybe that's asking too much).
Roll bar stiffness - diamater, length and arm length would be better. If you could include blade type ARB adjustments even better
Ackermann - pffff, I dunno. Whatever it had when designed.
Damping. I think we have some figures for what the dampers should be, but the numbers are something like 300/8, which is nothing like the values in LFS and/or your units. I don't know what units ours were.

And after putting in 'best guesses' it says the top speed is 113mph, about 20mph down. My excel one is accurate to +-2mph, and requires less data (admittedly it doesn't work out times to speed/distance, or cornering ability, or aero stability etc, but I wouldn't believe yours anyway as it would be too simplistic to rely on anyway).

some of those things are pretty easy:

- motion ratio: 1. put a jack under one wheel and raise it 1" 2. take a zip tie and put it on the shock shaft up against shock body. 3. lower the wheel exacly 1". 4. measure distance between zip tie and shock body. that distance is your motion ratio (i.e. how much the shock travels for 1" of wheel travel).

- unsprung mass: (this only works as long as you're using rodends in the suspension and not rubber bushes and the rodends are reasonably free and are not binding up). 1. put the car up on jackstands 2. put corner scales under each wheel (or just one front and one rear) 3. disconnect the shock/spring and a/r bar link completely. the scale will read the approximate unsprung weight for each corner. depending on how tight the rodends are i'd add 5-10% for friction. it may also help to raise the wheel off the scale and put it back down a couple times and take averages.

- brake torque is not difficult if you can measure your deceleration (in g) and know your tire diameter.

the things that are hard:

- CG height. you won't get that without having a spreadsheet or CAD model with every component and its accurate weight and location. measuring from roll angle is very error prone as it requires knowing your exact roll stiffness front and rear, the exact cornering g, the exact longitudinal position of the cg (which is the easiest of the bunch) and to some degree chassis torsional stiffness although on a race car that's pretty minor. you might as well just eyeball it or use 13" for a formula car just because.

- CD, aero centers of pressure, etc. you need a rolling road wind tunnel or a good and accurate CFD model with sophisticated software and someone who REALLY knows what they're doing. eyeballing it is absolutely pointless. even good data acq with motion and force transducers can only get you in the ballpark, depending on how sophisticated your filtering is and how carefully you run the tests. best you can do is guess whether there's downforce or lift and whether center of pressure is forward or aft of CG by how the car feels at high speed vs low speed. even coastdown tests would need to be performed very carefully and the results are not at all obvious since you have to filter out rolling resistance and drivetrain drag. it's far easier to 'reverse engineer' the CD if you know your horsepower and frontal area by looking at your actual top speed and rpm and then calculating what the CD must be to achieve that. you can get to within 5% of the actual number that way if your top speed is high enough where drag is the overwhelming factor, say 150 mph or so. at lower speeds you need to account for mechanical factors more.
dpcars
S2 licensed
for what it's worth i'm running vista (unfortunately) and project3 runs fine. i didn't do anything special, just unzipped everything into one directory.
dpcars
S2 licensed
Quote from Bob Smith :As for gearing, there are no defaults for each vehicle. Hence no settings change when you select another vehicle. That's what the setup files are for.

perhaps a default setup file per vehicle that is automatically loaded when vehicle is loaded might be handy? not a big deal, would just make it easier and more intuitive. right now if you go from a 4-speed car to a 7-speed car and just try to run the sim without redoing setup or reloading a setup file the results are a bit odd

Quote :
Regarding the gearing going haywire, the gearing analysis is updated everytime you change a number. Typing zero is below the minimum value of 0.5, so it is chaged to 0.5 automatically. The trouble is this positions the cursor back at the start. You now type an 8 (trying to make 0.8) and have ended up typing 80.5, which is above the upper limit of 7.5, so it is reduced to this number. The logic does not permit a higher gear to be shorter, so the gears above are set to this number, if they are not already higher. Since 7.5 is the maximum, they can't be, so all ratios end up as 7.5. Agreed this is not an ideal situation. Luckily if you know to reposition the cursor manually, this isn't a problem. I'll look at moving the cursor automatically.

would there be any harm in setting the minimum at 0 instead of 0.5? if someone actually leaves a gear as 0 it can be skipped when the sim is run. just an idea for another way to solve the problem.

overall, great work! let me know when i can put a link to it on my site.
dpcars
S2 licensed
looks good (hopefully dp1 will be back soon - is there a way to model the center sprag? if not a 30/70 torque split works ok)

one minor thing - how come the picture of the bmw f1 car says 'renault' on it?

another small item - units preference does not propagate to vehicle tools when creating a vehicle. if i set units to imperial and save preferences, vehicle data is still in metric. yes i know i can use the units converter but would be more convenient if the same units applied throughout. not a big deal of course.

also, in gearing setup the text boxes don't seem to accept overdrive (0.xx) selection - the whole thing goes haywire. using sliders works fine though. when switching vehicles gearing setup seems to remain from the previous vehicle and does not appear to switch to vehicle defaults. overall the gearing setup functionality seems a bit unstable (i'm running on vista btw, if that has any bearing on it - a horrible OS that came with my machine and i'm thiiiis close to actually buying a copy of XP and reloading the whole thing).

haven't played around too much with other functions but what i did try seems to work well.
dpcars
S2 licensed
Quote from MAGGOT :I always thought the DP1 would be a very nervous car at high speeds, due to the short wheelbase.

But man... it sure does look fun!

it has same wheelbase as UFR. some of the perceived 'nervousness' of the prototype may be due to alignment and/or aero weirdness, it's too soon to tell. changing front toe from in to out definitey helped. and maybe i just need to get used to it. the fastest i've gone in it so far is 126 mph. i've spun it twice, both at low speed and both under braking. i did manage to catch a number of slides so it is doable. because the driver sits fairly far back in the car it is very easy to tell what the back end is doing. however i would imagine without the seat-of-pants feedback slides/spins would be much harder to catch in LFS because it all happens FAST. if anyone here has ever driven a 125 shifter kart, the dp1 drives VERY similar to that.
dpcars
S2 licensed
Quote from srdsprinter :Lol... That certainly is one opinion.

In fact I'd estimate that the DP1 would be one of the most usable and controlable cars in LFS. It has AWD and Slick tires... Low and Central COG, and probably the largest mechanical grip of anything but maybe the FXR. Its designed that way IRL, and would presumably carry over to LFS.



Again, unquestionably? The RA has no downforce, the DP1 may have weaker aero than fox, but Mechanical Grip will be much higher, and will have considerable aero.

I imagine, in LFS speak, it would be a cross of some of the easy drive behavior of a FXR XFR mix (low weight and AWD), the lightness and handling similar to the FOX, and the outright accleration somewhere close/between the FO8 and BF1. Just my guesses, but have you even looked at the design of the car?

P.S. any upcoming trackdays planned for any of your toys DP?

so far based on the prototype testing and whatever acceleration sims were done, the v8 dp1 should actually out-accelerate BF1 up to around 80-90 mph simply due to better traction. at over 100 BF1 would pull away definitely. the main advantage of dp1 is the ability to put power down out of corners, it is quite evident even in the prototype. to give an LFS example, if you mash the throttle on medium or low speed corner exit in FO8 or BF1 the back end will want to take the lead. do the same in UFR and the front end will run wide. the dp1 is between the two (for obvious reasons), it just pulls cleanly out. also, mechanical grip should be pretty much unmatched due to very wide track, lots of rubber on the road, very low unsprung weight (small wheels/tires, inboard brakes and shocks). so on tighter tracks dp1 may well be the fastest car out there.

where the car is at a bit of a disadvantage is on long straights and high-speed corners, it tends to be a bit 'nervous' and if a spin does develop it's very difficult to catch. the solution is to always be ready to apply more power, it stabilizes the car. so on longer tracks with high-speed corners and long straights the power and downforce of BF1 would make it faster. possibly the FO8 as well, but that's a close call. well, that's all assuming dp1 ever makes it into LFS

anyway, this is all just theories at this point and everyone is entitled to their own theory
Last edited by dpcars, .
dpcars
S2 licensed
Quote from DaveWS :

Patch W car sounds any better to you? (seeming as you aren't in the situation where you are used to the old ones)

they do, although IMO audio remains something that could be improved... it seems the major challenge is finding actual car sounds? i don't know much about doing sound files but if you let me know exactly what is needed, i could try sending my friend's DAT deck along for a ride in a few cars over the summer. it's a bit unpredictable as to who is running what and when but generally cars are here and i do have varying access to them, though some may take a while to get. if this would help just email me direct with details and wish list...
dpcars
S2 licensed
Quote from Mister2zx3 :90fps with a a full grid of AI cohorts? nice.

As for Xbox "sims" even Forza2 and others fall so short of real driving, it's pretty much a big black eye for the console racing genre how poorly it is implemented. And even worse how it is defended/excuses made.

nope, that's solo. haven't really played much with multi-car stuff, ai or otherwise. same goes for setups - i tried a few changes just to see what they do but that's about it.

i'll get to it eventually (better be AFTER the atom is running!)
dpcars
S2 licensed
been playing with the W patch on my newly built system - finally can run it at 1920x1080 and it looks great! getting over 90 fps at that resolution at LOD 1.0 when i don't limit it. whether my car will ever make it into the game or not i don't know (would be great, obviously) but i like the improvements in rendering. as i said before, i'm sure the devs can manage their priorities

btw, after a couple RL trackdays i got a whole lot worse at LFS - not that i ever got good at it to begin with but it is more clear to me now where the differences in skillsets lie. LFS is definitely useful and continues to impress. a friend of mine tried it yesterday and immediately asked for the link to download. he is a hardcore car guy and was involved as a sort of informal 'consultant' in development of both PS and Xbox games a couple years ago (one of his cars was recorded on a dyno by microsoft for the game sound) and he said it was the fist time he saw a game that was reasonably close to driving, as opposed to just being a game.
Last edited by dpcars, .
dpcars
S2 licensed
Quote from srdsprinter :DP, slightly off the LFS topic, are you planning on doing any autocrossing or hillclimbs as part of DP1 development? It obviously seems secondary to track testing, but these would be the logical places where the production DP1 could be used in competition.

both a/x and hillclimb would be great competition venues for the car once it's done (h/c especially, what with power/weight and traction), but as development tools they are far from ideal. you get very little tracktime per event and only see the course a couple times so a huge portion of performance is determined by driver's ability to quickly figure out the course and navigate it. track testing on the other hand is repeatable and provides a lot of seat time. the track becomes a non-factor because it's a given and so the testing can focus on how the car behaves. it is also easy to experiment with different lines/strategies from one lap to the next and immediately see the results in datalogs.
FGED GREDG RDFGDR GSFDG