W.I.P. Grand Prix de Trois-Rivières road layout

[maruto]

http://code.eng.buffalo.edu/dat/sites/tire/tire.html
https://en.wikipedia.org/wiki/Friction#Coefficient_of_friction
https://www.google.com/search?sxsrf=ALeKk02xgtp-708l5_TaY719m07FO-hhog:1600082540222&source=univ&tbm=isch&q=coefficient+of+friction+table+for+vehicles&safe=active&sa=X&ved=2ahUKEwjZgK_7w-jrAhUuvlkKHXj2BeQQsAR6BAgKEAE&biw=1920&bih=937#imgrc=POGaQO5w-Cqx-M&imgdii=M_bZlbiCE-VABM
Sorry, it's theoritical.

Well Sir, thanks for the theory on friction coefs, it reminds me that my physic lessons from CEGEP are quite some years behind me, maybe you can clarify that for me...

If i understand your note, we are interested here with the kinetic ( µk) of rubber against concrete (0.6 ... 0.85) vs rubber against asphalt (0.67)....(dry conditions) so in theory rough concrete has more grip than asphalt...

looking at your google search i found that page that explains it simply:

http://dev.physicslab.org/Document.aspx?doctype=3&filename=Dynamics_FrictionProperties.xml

rubber on concrete : 0.68
rubber on asphalt: 0.67

rubber on iron casted plates: ? (can you help me with that case?)

EDIT: found another source with different coef...
(https://www.engineersedge.com/coeffients_of_friction.htm)


I'll let the physical engine of Assetto corsa do the math, but we can translate that into the physical engine by attributing surface properties in relation of one another in a surfaces.ini file that will look like this:

[SURFACE_0]
KEY=ASPHALT
FRICTION=0.97
DAMPING=0
WAV=
WAV_PITCH=0
FF_EFFECT=NULL
DIRT_ADDITIVE=0
IS_VALID_TRACK=1
BLACK_FLAG_TIME=0
SIN_HEIGHT=0
SIN_LENGTH=0
IS_PITLANE=0
VIBRATION_GAIN=0
VIBRATION_LENGTH=0

[SURFACE_1]
KEY=CONCRETE
FRICTION=0.98
DAMPING=0
WAV=
WAV_PITCH=0
FF_EFFECT=NULL
DIRT_ADDITIVE=0
BLACK_FLAG_TIME=0
IS_VALID_TRACK=1
SIN_HEIGHT=0
SIN_LENGTH=0
IS_PITLANE=0
VIBRATION_GAIN=0
VIBRATION_LENGTH=0

[SURFACE_2]
KEY=PLATES
FRICTION=0.92??
DAMPING=0
WAV=kerb.wav
WAV_PITCH=1.3
FF_EFFECT=1
DIRT_ADDITIVE=0
BLACK_FLAG_TIME=0
IS_VALID_TRACK=1
SIN_HEIGHT=0
SIN_LENGTH=0
IS_PITLANE=0
VIBRATION_GAIN=0.4
VIBRATION_LENGTH=1.5

 

[Johnr777]

Well Sir, thanks for the theory on friction coefs, it reminds me that my physic lessons from CEGEP are quite some years behind me, maybe you can clarify that for me...

If i understand your note, we are interested here with the kinetic ( µk) of rubber against concrete (0.6 ... 0.85) vs rubber against asphalt (0.67)....(dry conditions) so in theory rough concrete has more grip than asphalt...

looking at your google search i found that page that explains it simply:

http://dev.physicslab.org/Document.aspx?doctype=3&filename=Dynamics_FrictionProperties.xml

rubber on concrete : 0.68
rubber on asphalt: 0.67

rubber on iron casted plates: ? (can you help me with that case?)

EDIT: found another source with different coef...
(https://www.engineersedge.com/coeffients_of_friction.htm)


I'll let the physical engine of Assetto corsa do the math, but we can translate that into the physical engine by attributing surface properties in relation of one another in a surfaces.ini file that will look like this:

[SURFACE_0]
KEY=ASPHALT
FRICTION=0.97
DAMPING=0
WAV=
WAV_PITCH=0
FF_EFFECT=NULL
DIRT_ADDITIVE=0
IS_VALID_TRACK=1
BLACK_FLAG_TIME=0
SIN_HEIGHT=0
SIN_LENGTH=0
IS_PITLANE=0
VIBRATION_GAIN=0
VIBRATION_LENGTH=0

[SURFACE_1]
KEY=CONCRETE
FRICTION=0.98
DAMPING=0
WAV=
WAV_PITCH=0
FF_EFFECT=NULL
DIRT_ADDITIVE=0
BLACK_FLAG_TIME=0
IS_VALID_TRACK=1
SIN_HEIGHT=0
SIN_LENGTH=0
IS_PITLANE=0
VIBRATION_GAIN=0
VIBRATION_LENGTH=0

[SURFACE_2]
KEY=PLATES
FRICTION=0.92??
DAMPING=0
WAV=kerb.wav
WAV_PITCH=1.3
FF_EFFECT=1
DIRT_ADDITIVE=0
BLACK_FLAG_TIME=0
IS_VALID_TRACK=1
SIN_HEIGHT=0
SIN_LENGTH=0
IS_PITLANE=0
VIBRATION_GAIN=0.4
VIBRATION_LENGTH=1.5

Keep in mind AC doesnt do well when going over small sections with a big friction difference, all 4 wheels need to be on similar frictions.

 

[physicsimulation]

Your engineers edge document is interesting.

I don't have definition for the "FRICTION" parameter within Assetto Corsa physical engine but, IMHO, I would put dry static coefficient of material since the driver would control acceleration (+ or -) up to the static slip ratio limit (see Vr=0 to Vs in my graph). This section has linear static coefficient upon slip ratio, therefore very easy to calculate.

IMHO, the engine could modify the "FRICTION" parameter dynamically when it's raining, icing, snowing, colder, warmer, ...

The slip ratio, or the relative speed, limit is function of the tire rubber compound and thread template (slick ... 4x4 ... paddle). Is Assetta Corsa physical engine handle this car parameter ?

To conclude, I would use these FRICTION values [static dry condition]
Rubber - Asphalt : 0.90 ( like street asphalt, in GP3R)
Rubber - Soften concrete : 0.60 (like kart concrete or board walk or painted vibrator ?)
Rubber - Rough concrete : 1.00 (like GP3R concrete in curves)
Rubber - Rubber : 1.15 (like track with rubber deposit)
Horseshoe - Rubber : 0.68 (like rubber on plates ???)
Rubber - Grass : 0.36 (not pertinent for GP3R classic track)

 

[Martin Dupuis]

thanks for the info on the iron casting plates, i'll use these dimension ; i wasn't too far....

Don't be sorry @Martin Dupuis , i'm grateful you took interest in the project and i'm pretty sure you will testdrive this track as the project evolve and provide me with feedback later on ... right now is still pretty raw , i didn'nt have much time to work on the track this week, I found a way to smooth the mesh, but not yet satisfied...

View attachment 5757

Open Optimisation question: when working with circular object in meshes, it creates a lot of triangles, how can we optimize that? for the visual mesh i was thinking of having a simple square quad mesh with the circular iron cast plate and simply use transparency. but for the physical mesh i would have liked to put the metal surface in a separate layer so that maybe we can feel when we drive over it...

It is too much going into details? when racing in real life, do driver have to be careful with those aera? is it more slippery? does it produce a different sound? I only tough about it because there is one right in the middle of Ryan corner.

Same thing for the concrete reinforcement in the corner, how does it compare in term of adherence with asphalt? Concrete must be harder so my guess it is has less adherence?

View attachment 5758

Thanks, I did try it out yesterday and I find it very bumpy too. Did you watch lilSki's track building videos ? I think he goes over smoothing the lidar data in his first or second video. The whole series is just a treat. Highly recommended !

 

[maruto]

Keep in mind AC doesnt do well when going over small sections with a big friction difference, all 4 wheels need to be on similar frictions.

yeah, i don't want anything fancy or unusual, i'll stay within kunos margins for friction materials ( maybe use this famous corner as reference...)

and i can try @physicsimulation hierarchy:

Concrete>Asphalt>Plates>Curbs

knowing that those numbers can easily be tweaked later.

Right now i just need to split and rename correctly the phys mesh according to those different materials.

IMHO, the engine could modify the "FRICTION" parameter dynamically when it's raining, icing, snowing, colder, warmer, ...

The slip ratio, or the relative speed, limit is function of the tire rubber compound and thread template (slick ... 4x4 ... paddle). Is Assetta Corsa physical engine handle this car parameter ?

Yeah, the AC engine take's all that into acount, before a race you can tweak almost every parameters, temperature, time, track state ( green, dusty, fast, wet) those parameters then affects the initial friction parameter set in the track surface.ini file.

and of course, every car has different tyre parameter ( slick, thread,....etc) that affect the car grip and handling..

this engine is more than 7 years old but has been so smartly build it is still in 2020 one of the most loved.
So powerful and versatile.
( million thanks to Kunos)

 

[AccAkut]

Open Optimisation question: when working with circular object in meshes, it creates a lot of triangles, how can we optimize that? for the visual mesh i was thinking of having a simple square quad mesh with the circular iron cast plate and simply use transparency. but for the physical mesh i would have liked to put the metal surface in a separate layer so that maybe we can feel when we drive over it...

For the case you have in your screenshot, are those manhole covers higher or lower than the road around it? If they are higher, I'd just go with intersecting meshes and not connect to round cover in mesh with the road below it. If its lower the way you did it there is as good as it goes. Just maybe less tris for the cover would be fine too.

 

[maruto]

@NiTZHD made some amazing 360 videos of the track a few weeks ago...

they will be really useful as reference for everything. Just like being there.

I only got few hours tonight to work on the track, september was so busy...

Started to work on the visual mesh, not there yet, got some scale issues, but it starts looking better than the googlemap

I splitted the visual mesh in 120m segments but since the track has real width difference in those wide corners, the texture get stretched on some part, creating some distortion.. need some more time to figure a way to do it. maybe i'll split those part in two to have regular 11m width mesh and a transition texture for the sides to the walls like i did in the pit aera...

 

[maruto]

GP3R v 0.1.3

-smoothed mesh, ( might need some more smoothing, but quite fun to drive)
-worked on road texture, concrete patches and metal plates.

any feedback welcome!

next step: the lines, the walls

 

[Martin Dupuis]

Nice update, the track is much smoother now.

I have two comments:
First, the pits and starting line spawns are not facing the correct direction.
Second, when you pass the start line in the middle, there's a weird glitch. Perhaps the mesh is not aligned correctly ?
See this video I put up.

Thanks again for the good work

P.S. Oh one last thing: the cement patches sound like curbs !

 

[maruto]

Nice update, the track is much smoother now.

I have two comments:
First, the pits and starting line spawns are not facing the correct direction.
Second, when you pass the start line in the middle, there's a weird glitch. Perhaps the mesh is not aligned correctly ?
See this video I put up.

Thanks again for the good work

P.S. Oh one last thing: the cement patches sound like curbs !

Thanks Martin for the feedback, here's a correction for the spawn point ( hotlap and pit) facing the good way, it's just a quick fix, i'll be redoing the spawn points correctly when i do the starting lines... (remove .txt and overwrite the same file in the track directory)

I tried to recreate the glitch you are talking about in your video but to me when i drive everything is fine... the mesh is not splitted at the start it is continuous... maybe it's a replay thing?? do you experience it every lap?

and yeah i experimented with curb sound over concrete, it might not stay, it was just a test, you can disable it by removing this line in the surface.ini file found in the data folder:

just change

WAV=kerb.wav

to

WAV=

(the skip barber is fun on this track! i managed 1.21 this morning but the wheels locks easily need some more time to master that little beast )

 

[Martin Dupuis]

Thanks Martin for the feedback, here's a correction for the spawn point ( hotlap and pit) facing the good way, it's just a quick fix, i'll be redoing the spawn points correctly when i do the starting lines... (remove .txt and overwrite the same file in the track directory)

I tried to recreate the glitch you are talking about in your video but to me when i drive everything is fine... the mesh is not splitted at the start it is continuous... maybe it's a replay thing?? do you experience it every lap?

and yeah i experimented with curb sound over concrete, it might not stay, it was just a test, you can disable it by removing this line in the surface.ini file found in the data folder:

just change

WAV=kerb.wav

to

WAV=

(the skip barber is fun on this track! i managed 1.21 this morning but the wheels locks easily need some more time to master that little beast )

Thanks maruto, I will try it tonight.

As for the start/finish thing, that wasn't on replay. I'll try to see if I can get it to glitch with other cars as well.

 

[maruto]

V0.1.4 (Download here)
-------
new smoother mesh. still some nice bumps.
new tarmac on boulevard du carmel. that mesh has been smoothed twice as much.
white and yellow lines.
raised concrete and metal plates 1cm above tarmac ( as @AccAkut suggested, gives a slight bump in and out of the slab, subtle)

I'd like to know how you would handle the transition between tarmacs? I was thinking of putting a simple plane with a texture of the dark tarmac and a irregular alpha contour on top of the junction..

I have issues on the near and far distance, while driving the lines don't blend correctly to the tarmac as they do in closeup.. (they are 1m long meshes raised 2 cm above tarmac...) scale or depth problem?

(I know i have read something about lines somewhere in this forum but spent almost an hour trying to find it but failed....I'll start searching again, but if a good soul knows where to find the info... )

here are my settings:

Thanks

 

[Leonardo Ratafia]

mesh feels pretty good so far!

 

[Johnr777]

V0.1.4 (Download here)
-------
new smoother mesh. still some nice bumps.
new tarmac on boulevard du carmel. that mesh has been smoothed twice as much.
white and yellow lines.
raised concrete and metal plates 1cm above tarmac ( as @AccAkut suggested, gives a slight bump in and out of the slab, subtle)


View attachment 5857


I'd like to know how you would handle the transition between tarmacs? I was thinking of putting a simple plane with a texture of the dark tarmac and a irregular alpha contour on top of the junction..

I have issues on the near and far distance, while driving the lines don't blend correctly to the tarmac as they do in closeup.. (they are 1m long meshes raised 2 cm above tarmac...) scale or depth problem?

(I know i have read something about lines somewhere in this forum but spent almost an hour trying to find it but failed....I'll start searching again, but if a good soul knows where to find the info... )

here are my settings:

View attachment 5856

Thanks

Dont think road lines, transition planes have been covered, but we did talk about skidmarks at one point, which is basically the same concept: https://assettocorsamods.net/threads/skid-marks-material.131/

The transparency option in kseditor has to be either enabled or disabled based on the shader used. AT or AlphaBlend. As well as "cast shadows" turned off

 

[maruto]

Dont think road lines, transition planes have been covered, but we did talk about skidmarks at one point, which is basically the same concept: https://assettocorsamods.net/threads/skid-marks-material.131/

The transparency option in kseditor has to be either enabled or disabled based on the shader used. AT or AlphaBlend. As well as "cast shadows" turned off

Thanks, i'll have a look at it and try both shaders to figure out wich is best in that case.

..

they seems quite similar, any peculiar use for each?

KsPerPixelAT seems to be ok with transparency off, with transparency on, the lines are drawn only in a close radius

KsPerPixelAlpha has this extra alpha parameter. Below a certain range(1.5) and it has the same effect of ks..AT with the transparencie on: the lines apear only really close to the car.


alpha parameter at 1.5 and above, the transparency get's drawn further away but it is thicker...like if it's some kind of a multiplier to the alpha chanel??At 5 it it completely opaque and really bright.

i'll do further tests.
..

(btw j, congrat on your release of MoSp, it's fantastic.)

 

[maruto]

 

[physicsimulation]

J'ai vu passer cela "How to extract contour lines And DEM from Google Earth"

 

[maruto]

J'ai vu passer cela "How to extract contour lines And DEM from Google Earth"

Merci de penser à nous!

nice find, Google earth data is less precise than LIDAR scans, but it can be useful for backgrounds or tracks where no lidar data is available.... I did my first one using google earth data but i did it by hand, not really precise, using this technique would have been better and faster i think.

 

[maruto]

One thing after another....

Depailler corner:

 

[maruto]

Working on walls and fences, wrote a script to automate it's creation from a single spline drawn on a plane, projected onto the mesh , extruded and mess them up a little not to be too regular...

not there yet; but holydays are coming, i'll get back at it!