alanevo/unitychrono4

Port of Chrono Works 4.0 physics engine to Unity3D.

unitychrono4's Issues

How can I use it?

It seems that you transfer the chrono engine in unity to replace the default physics engine? Is the pychrono still working?

Contact error

There is an index out of range error regarding the contact adding and removing in the ChContactContainerNSC. Mostly noticeable when a contact leaves a collision with another object, what's making this a tricky error to trace is that it appears to be fairly random. This error needs to be addressed because it does create physics issues, mostly noticeable with sphere objects, they spin out of control and sometimes pass through other static objects.

No Generics

Not so much an issue but more a look into it at a later date. Original C++ version of chrono uses templates for the Matrix and other core classes, like Vector and Quaternion, so you can pass a int, float, double or long precision, now C# Generics work in a different way to C++ templates, C# uses full object oriented programming so templates are resolved and compile time whereas Generics continue into runtime.

So, the main problem I have here is that if I use Generics for the core classes you can not use mathematics unless I use the dynamic conversion. At the early time I didn't see an issue with this until I ran into cpu ms issues, when I ran some speed tests I noticed if I used a dynamic conversion on mathematics, eg.
T a;
T b;
a += (dynamic)b;
This appeared to run 20x slower than if it used doubles with not dynamic.
So for now the core classes are not Generic, it is just double precision type.

Performance issue

When the simulation is set to a step of 0.001 there is a massive spike in cpu ms, anything up to 20x slower. Possible cause could be the garbage collection with the objects being created in the FixedUpdate. So far I have only noticed this issue with the LinkLock objects.