If you are using the Finite Volume Method in Pachyderm, hopefully you have been wondering about the lack of documentation on my very elaborate and less than intuitive interface tools.

I am working on it, but there is less time available for this stuff these days. Please bear with me.

See the new tutorial page dedicated to the Pachyderm_Numeric_TimeDomain Method here, and proceed with caution. If in doubt, please contact me.

Remember that under the GPL, you are responsible for your own application of these tools.

We have updated the downloads section. (apologies if anyone has been wondering where to download the software... we were unaware that our web host had deleted the download files... If anyone knows of a reasonably priced and reliable web host, we are open to suggestions).

The release candidate that is linked is not perfect, but we think it is very usable. It includes improvements such as:

- First order Biot Tolstoy Medwin edge diffraction

- Transfer Matrix materials design, including sensitivity to indicdent direction and a method for finite size correction (don't use a smart material if you are going to use the finite size correction)

- Finite Volume Method, including an eigenfrequency calculator that is great for modal detection, a method for determining the correlation scattering coefficient, and a great system for visualizing wave behavior.

- Multiple source objects, Common Loudspeaker Format (CLF) and arbitrary directionality support.

- Line sources: Traffic noise, and aircraft takeoff and landing.

 

- Auralizations over any speaker array you can design

- Smart particle animation (this is something we invented ourselves... it is very similar to other particle animations, but at every frame, each particle searches for its nearest neighbors, and they share energy, leading to a more visually coherent result that is easier to read)

- Animation over maps

- Support for Grasshopper, including icons (thanks to Pantea Alembeigi, RMIT)

- Support for IronPython

After 3 years, I have the source code posted to Github. This includes not only my work-in-progress code from the Rhino plugin and Hare library, but also the code for the elusive Grasshopper plugin. With this, I announce the release candidate period for Pachyderm 2.0.

There are many new features - far too many for me to name... a lot has happened in three years, and Pachyderm has grown with me. However, I am hoping that it's growth can be accelerated by benefiting from the growth of others as well, which is why the code is no longer under lock and key (a rather timid approach to open source which I am entire responsible for), but freely available on Github. It is my hope that those of you who are as interested in acoustics and design in simulation will come forward and contribute.  (I know you're out there... you emailed me just the other week. Come on... you know you want to!)

All repositories can be found here:

https://github.com/PachydermAcoustic 

A few caveats if you download it just to use it - this is far from a finished product. At a certain point, you realize that if you keep postponing publication just to resolve all of the experimental implementations of the project it will never reach the outside world. The core functionality is solid, but here is a list of a few things to be cautious about when using:

- Absorption coefficient calculation - this works great for Equivalent fluid models and finite samples, but the other models will throw an error or crash, (because they are unfinished.) Please explore it, but be careful.

- Finite Difference Time Domain - oh where do I begin... this very enticing technique is brilliant in its simplicity, and confounding in its limitations. I have opted to use a fourth order accurate scheme (27 point 3d stencil) however, this has proven problematic, as the model will not always successfully build. If it is unsuccessful, there will be red and blue boxes where the model was unable to resolve the boundary condition. Should you choose to run it with one of these, the program will crash. There is usually a configuration which will run, but finding it requies fiddling with the max frequency and placement of the model. Additionally, it is solely for visualization at this time (until I or someone else can find a way to make its use practical).

- Edge Diffraction - This version includes Biot Tolstoy Medwin edge diffraction according to the brilliant work done by Peter Svensson, Paul Calamia and others. The implementation seems solid and quick for first order, and the output looks plausible, but has not been benchmarked. Higher orders are not implemented yet.

- Surface Sources - This works, but initial power is wrong, which means that for now, I do not recommend using it. Line sources and point sources work fine.

- Auralization has moved to its own control. You start by picking which interface you would like to pull results from to create an auralization, and then setting the channel configuration and dry signal. I think there are still a few crash-bugs in it, so please let me know if you find one.

That's all I can think of for now, so have fun, and if you find anything else that is worth asking me about, please do. You know where to find me. (I don't bite. Please let me know.)

It looks like the images did not transfer over when I upgraded the site. My apologies for that. I will try to get them back, but it may be a few weeks. If it turns out that I can't, then I will post new ones when I have v2.0 benchmarked.

For those of you who mentioned the benchmarks in particular, the images were posted there for years, and my seasoned users know how well v 1.0 benchmarked. I promise that this is no deception on my part - It is just one of the hickups associated with a site upgrade.

All the best,

Arthur