scrawk / position-based-dynamics Goto Github PK

It seems that the distance constraint function is different from the one from C++ version.
In your code:

double invMass = 1.0 / mass;
double sum = mass * 2.0;
corr = CompressionStiffness * n * (d - RestLength) * sum;
Body.Predicted[i0] += invMass * corr * di;

But in the C++ version:

Real wSum = invMass0 + invMass1;
corr = compressionStiffness * n * (d - restLength) / wSum;
corr0 =  invMass0 * corr;

The results are different even though I assume mass0 equals to mass1.
Is it a bug or something else?

And I also wonder what's the theory of your bending constraint? The C++'s bending constraint is different too.

Finally, thanks for your contribution in PBD's unity version which helps me a lot!

double wsum = 0.0;
int numParticles = Body.NumParticles;

for (int i = 0; i < numParticles; i++)
{
     RestCm += Body.Positions[i] * mass;
     wsum += mass;
}

RestCm /= wsum;

Is the result of RestCm equal to the sum of body positions?

int numParticles = Body.NumParticles;
double wsum = mass * numParticles;
for (int i = 0; i < numParticles; i++)
{
     RestCm += Body.Positions[i];
}

Do we have self collision for cloth included in this project? if so please do tell me which script is it in? thanks in advance.