kinetic friction decremental

[Overhertz]

Is it possible to have dynamic traction, as an object slides faster, the traction should become lower. E.g.

Code: Select all

  NewtonMaterialSetDefaultFriction(ge_NewtonWorld, MaterialA, MaterialB, 1, 1.25);


lets say it starts like this, but as the objects velocity becomes higher, i want the kinetic friction to become lower, is this possible?

Thanks in advance.

[Julio Jerez]

lets say it starts like this, but as the objects velocity becomes higher, i want the kinetic friction to become lower, is this possible?

Kenetic friction is contant regarless of the speed of the objects. That is wha teh engine solver model.
if you want velocity depended frictions you need to add drag in the force and torque callback.

[Overhertz]

i'm not sure i could do this via the callback, the problem is, i've created a multi body car, if i set the friction high, it grips and accelerates good, but if turning at high velocity, i don't want the friction any longer, since the car should drift or slide, not roll over at 20 kph

any ideas how else i could solve this problem?

[Julio Jerez]

If you look at the SDK demos in core 300. you will see that I am started to bring back the car.
I had to stops because ther are missing element that I have to complete first.
In core 300 I am bringing back the car of core 1.00 with some improvements

I tried to take shortcut in core 200 to make a faster car for both, mutibody and the raycast, and the result was a bad in both cases.
if you give me a week or so I will have the car back working, and believe me the car will cover all different type of vehicles:
realistic to the point that the user one, to arcaide. tracked, wheeled, and any other combination.

I made the test unit, but I had not time finish yet.
I needed the the convex cast working, but that cascaded in to the collision instance, and so on.
now I have everything, so if you give that some time I beleive you will be please with the result.

[Sweenie]

if you give me a week or so I will have the car back working

I'm waiting for this like a kid waiting for Santa on Christmas.

[Overhertz]

Julio Jerez thank you for that news, it is like music to my ears, in that case i will wait and work on other elements )))

[Julio Jerez]

The feature I am adding now is serialization on all element of the engine.

I just completed teh serialization of collision (pending scene, and softbody collision with are incomplete still)
I am adding world serialization, Bopdy seralization and Joint serilazation.

wit thsi options, teh cline application can for get stuff straing form teh SDK demo and pate into they code.

say for example I complete the car, the I call
NewtonSerializeBody (...)
NewtonSerializeJoint (...)

and this will save the dat to a pice of memory, or a file all determened by the end client.
then in theo applicationb the application can call the derialization founstion for that feature, and
badabin badabum, the feature will be imported into the game. all teh application have to do is set up a cople of pointer for teh use data, and the callbacks.

this is sthe glue code for serialization of an entire world

Code: Select all

//static char* MAGIC_NUMBER = "serialize data";
static void SerializeFile (void* const serializeHandle, const void* const buffer, int size)
{
   // check that each chunk is a multiple of 4 bytes, this is useful for easy little to big Indian conversion
   _ASSERTE ((size & 0x03) == 0);
   fwrite (buffer, size, 1, (FILE*) serializeHandle);
}

static void DeSerializeFile (void* const serializeHandle, void* const buffer, int size)
{
   // check that each chunk is a multiple of 4 bytes, this is useful for easy little to big Indian conversion
   _ASSERTE ((size & 0x03) == 0);
   fread (buffer, size, 1, (FILE*) serializeHandle);
}

static void BodySerialization (NewtonBody* const body, void* const serializeHandle, NewtonSerializeCallback serializecallback)
{
   // here the use can save information of this body, ex:
   // a string naming the body, 
   // serialize the visual mesh, or save a link to the visual mesh
   // save labels for looking up the body call backs

}

void SerializationWorld (const char* const name, NewtonWorld* const world)
{
   char fullPathName[2048];
   GetWorkingFileName (name, fullPathName);
   FILE* file = fopen (fullPathName, "wb");

   NewtonSerialize (world, BodySerialization, SerializeFile, file);
   fclose (file);
}

[PJani]

Can't wait for vehicles GOOD news

Anyway would it be possible to have vehicle joint as joint for one wheel instead of one joint which holds all wheels?

[Julio Jerez]

I start refurbishing the joint today.
I can add a wheel joint, however a wheel joint is not really a vehicle, al vehicle is a contraction,
but it requires a lot of skill to go around the round error problems you get when joint move a high different speed, and at the same time they have high mass ratios.

Iwill fucus on teh vehicel package, then I can extract they wheel.

[Overhertz]

Hi it has been a while since i checked back, just wanted to check if you got any further with the vehicle system?

[Overhertz]

has the forum died or what??? :/

[PJani]

Nop it didn't its just a slow week

Julio is working a lot on fixing bugs and continius collision mode if i am not mistaking.

I am waiting for proper vehicles too, since upgrade from 1.53 to 2.xx. Mean while i do other things on my project

[Julio Jerez]

Not it is not, I need to get the continue collision with champhered cylinder going before I add the new vehicle

[Overhertz]

okay... i will keep checking back, thanks for replies