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Ecotect Tutorial : Displaying Acoustic Rays

Synopsis

In this acoustics tutorial, we will look at how to generate and display acoustic rays and particles in an Ecotect model.

Duration

You will need about 40 minutes to complete this tutorial.

Training and Accreditation

Successfully completing this tutorial fulfills one of the practical skills required for completing Level 1 of the Acoustic Design training module.

Resources Required

To complete this tutorial, you will need the AcousticRays.eco example file. This can be found in the 'Examples' folder located in the folder where Ecotect is installed on your computer.

Tutorial

  1. Open the AcousticRays.eco file in Ecotect.
  2. Click on the Rays and Particles control panel.
  3. Select the speaker object positioned on the stage of the auditorium. In the Rays and Particles control panel, click the Source to tag this object as the point of origin for your rays and particles.
  4. If you wish to isolate particular surfaces in your model for analysis, select them and then click the Reflector»Tag Selected Objects to only use these surfaces for generating rays and reflections. Otherwise, Ecotect assumes that all surfaces are to be included in the analysis (see below for further settings).
  5. Next, specify how the rays are to be generated. For the purposes of this tutorial, set the ray type to Circular Pattern, the Azimuth Angle to 90, the Axial Rotation Angle to 90, the angular increment to 0.5 and Bounces to 8.
  6. That's it! If you wish to test just the surfaces you identified previously as reflectors, make sure the Only Test Reflectors checkbox is ticked. Otherwise, click the Generate Rays button to start the ray/particle show!
  7. Based on the settings you have specified, Ecotect will now generate rays and particles from the nominated source point. This will continue until all of the settings you specified have been fulfilled. Press the ESC if you need to abort the process (note: check the Ecotect status bar at the bottom of the screen to see when the ray animation has completed - even though it may look like nothing may be happening on screen, Ecotect may still be calculating ray bounces too small to display on screen).
  8. Once the ray animation has completed, you can now use the display settings part of the control panel to change the way in which your rays and particles are visualized on-screen. To start with, select the Static Rays option. With the default display settings, this will show an indecipherable mass of black lines in your Ecotect model, being all of the rays and their subsequent bounces displayed simultaneously.
  9. In order to make some sense of this display, you will need to adjust the settings used to generate the ray display. Try reducing the azimuth angle to 90, increasing the angular increment to 6 and reducing the number of bounces to 4, and then click the Generate Rays button to recalculate the ray display.
  10. Now, under the display options part of the control panel, select the Show Reflection Depth display option. This should result in a more coherent display of the acoustic rays in your Ecotect model. What you see here is a reduced number of rays and reflections (projecting only towards the auditorium), colour coded by the number of times each ray has been reflected by a surface.
  11. Let's have a look at the next display option, Reflector Coverage. To use this display option most effectively, regenerate the ray display using the following settings : Spherically - Random, Azimuth Range 90, Altitude Range 90, Number of Rays 4000 and Bounces 4. Lastly, set the display settings to Show Relative to Direct. Using these settings, you are able to see which surfaces in your model are contributing useful acoustic reflections.
  12. To further analyze these reflections, try selecting just the floor surface of the stage. This restricts the display to only those rays that reflect off this surface. As can be seen, the floor surface of the stage contributes the majority of direct (ie. good) acoustic rays to the auditorium.
  13. Next, hold down Shift and add to the selection the underside of the bulkhead above the apron of the stage. Note how the display legend changes - Ecotect colour-codes the reflections that occur in relation to each selected surface.
  14. You can also display numerical values for each of the reflection points in the model, rather than just relying on visual analysis. In the Numerical Display drop down list, select Delay (ms) and the values will be displayed in the model (zoom in to make it easier to read the values, or select fewer surfaces at a time). Displaying numerical values in this way can be useful when determining if reflections are better suited towards speech or music.
  15. The next display setting option is Surface Incidence. Select this option, using the same ray and particles as from before. This option displays all of the points where rays intersect with surfaces of the model. You can isolate particular surfaces for display by selecting the required objects. Note that depending on what settings you have used to generate your rays and particles, it may take a long time for Ecotect to regenerate views of your model.
  16. The Animated Particles and Animated Rays display options allow you to view an animation of the rays/particles in your Ecotect model.
  17. Adjust the ray generation settings to the following values - Spherical - Random, azimuth angle to 90, altitude range 90, number of rays 2000 and bounces to 2, and then click the Generate Rays button to recalculate the ray display.
  18. Select the Animated Particles display option. In the animation part of the control panel, press the Play] button. This will display an animation of the acoustic particles moving throughout the Ecotect model. Don't forget you can adjust the legend used to display the particles as you have previously.
  19. The Animate Rays display option works in a similar fashion to Animate Particles, except that it display the entire path of the particle as it moves throughout the model. Consequently, you might find this display option easier to interpret if you first reduce the number of rays and bounces in the ray generation settings.
  20. You can use the Elapsed Timeslider to view the ray/particle propagation at any point along the animation timeline. Alternatively, if you have the Mouse Wheel Control option checked, you can use the scroll wheel on your mouse to move either forwards or backwards along the animation timeline. The speed/increment distance is controlled by the value in the text box next to the Play button.






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