Pachyderm Numeric_Time_Domain

Replies to This Discussion

Permalink Reply by Daniel Horta on March 17, 2018 at 11:02pm

Could anyone share experiences with the calculations of the modes in a non-rectangular room in the Eigen Values tab?

Permalink Reply by Daniel Horta on March 17, 2018 at 11:56pm

Every time that I run a simulation my computer takes several minutes but nothing happens. Maybe I'm setting thins wrong... Please, someone help me with this!

Permalink Reply by Arthur van der Harten on March 20, 2018 at 2:22pm

Hi Daniel,

The Eigen values tab is meant to calculate a list of eigen frequencies. To my knowledge, it still works. Can you be more specific regarding the issue you are encountering?

Arthur

Permalink Reply by Daniel Horta on March 20, 2018 at 3:09pm

Apologies for my lack of specificity.

The problem is that every time I simulate something on this tab, even with simple rooms, nothing happens.

The simulation continues, and I do not know if it's normal to take so long or I'm missing some initial configuration.

Cheers, 

Daniel

Permalink Reply by Arthur van der Harten on March 20, 2018 at 3:12pm

Hi,

This depends on a lot of things... how big your room is (not how simple), the specs of your computer, etc.

If you can check the taskmanager, and Rhino is still cranking, you can bet that the simulation is doing exactly what it is supposed to. Maybe try with something smaller... like the size of a typical bedroom.

Arthur

Permalink Reply by Daniel Horta on March 20, 2018 at 4:13pm

Ok, Arthur, I will try this.

Besides that, if it's not too much work, could you explain me roughly how to use the visualization tab?

Permalink Reply by Arthur van der Harten on March 28, 2018 at 9:09pm

Hi Daniel,

My apologies. I did find an issue with the Eigenfrequencies tab. Please go to the site, and download the new version, released tonight.

Regarding visualization, here is how it works.

1. Pick your frequency, and your frequency max. Frequency should not be more than the frequency max you chose (obviously).

2. Have a model, and at least a source object.

3. Click 'Calculate Run'. This will preprocess the model, and then the driver will begin emitting signal. A visualization plane will be added dead center of the model space (which will correspond to the bounding box of all surface and polysurface geometry).

4. You can use the controls just below the 'Calculate Run' button to control the color scale, and or move visualization planes.

5. Experiment!

Have fun.

Arthur

Permalink Reply by Daniel Horta on March 28, 2018 at 9:35pm

Hi Arthur,

Thank you very much for check that about the Eigenfrequencies tab. I really appreciated!!

And also thanks for explaining how to use the visualization tab.

These last days I started to really study about FEM based software like Ansys. There's one call COMSOL Physics that has a module dedicated to Acoustic.

Anyway, very excited about that new version of Pachyderm. What're the updates?

Cheers,

Daniel

Permalink Reply by Arthur van der Harten on March 29, 2018 at 5:36am

Hi Daniel,

The main updates are improvements to auralization (which you might find is less cumbersome and more reliable now) and Edge Diffraction. I have also marked in the areas of the software that are 'Experimental', so it is more clear what areas would require a higher level of expertise in the workings of the tool. Much of this

I used Comsol a few years ago. It is good, but it requires a very high level of expertise, not just in acoustics, but in material science. Additionally, it is obscenely expensive, which is prohibitive when it comes to its use for architectural acoustics. Generally speaking, the loudspeaker and product engineering industries tend to use it. (The same goes for Ansys, although Ansys is more widely used for CFD and structures.)

Arthur

Permalink Reply by Daniel Horta on March 29, 2018 at 7:40am

Hi Arthur,

I'll test those improvements. Thank you very much for the update. I think the Material Design Tab has some problem with the resolution of the screen.

About the FEM software, I totally agree with you. I'm on trial period of COMSOL and I'm only using to find the Modal behavior in non-rectangular rooms. I didn't have the opportunity to explore more, yet. And with Ansys is like you said, mainly for Fluid and Structure analysis. I tend to use Ladybug or Diva the majority of the time and when I want some more in-depth analysis I use Ansys. Luckily I'm in college and the company that makes Ansys give academic license for students.

Permalink Reply by Arthur van der Harten on March 29, 2018 at 8:53am

I guess I tend to work on larger screens than you do... I will see what I can do about that.

Arthur

Permalink Reply by Antigoni Karaiskou on May 4, 2018 at 1:53am

Hi Arthur,

Thanks for the open source Pachyderm plug-in. I would like to ask some questions for the Scattering analysis. I'm currently doing my thesis and the idea at this stage is to compare some scattering surfaces. I had the previous version installed (February) and I had some interesting results. However since I installed the update(March) my results for the same samples (placement/radius/depth) don't make sense any more(see attachment). Maybe is something wrong with the code? And some more questions: Do you think 1m sample is enough for the simulations? what about the edge of the sample (circular, square, random)? Last but not least do you think that the correlation coefficient provided in Pachyderm can be used to compare scattering performance of different samples? I'm running out of time so any feedback would be more than welcome. :) Best, Antigoni