(unfortunately, some answers only in German language, sorry)
1. I have digitized acoustic elements, however, I can’t find them in the model ??
Sometimes it is difficult to spot all acoustic elements in your noise3D model, especially when working in 3D. Sources e.g. may be positioned slightly below the roof of a building and thus “hidden” to the user. For that reason when possibly becoming confused about “where you are” in the model it may be usefull to switch into the X-Ray modus. In X-Ray all faces are beeing turned transparent. Therefore, any “hidden objects can be identified more readily. X-Ray works as follows: Please proceed in SketchUp View → Face Style → X-Ray. Then your model should turn into an x-ray status: Switching back into the normal modus can be achieved in the same way.
2. Data Exchange from noise3D with GIS Systems (e.g. ArcMap)
When you consider exporting data from SketchUp to a GIS system then there are different opportunities. As an example, getting SketchUp date into ArcMap or ArcGis. In such case it is recommended to use the Collada format which is “ *.dae”. Collada formats can be imported into Arc GIS software and vice versa. The following YouTube video demonstrates how this can be achieved very elegantly: YouTube Video
3. noise3D works with OpenStreetMap
4. How to calculate noise levels at a skatepark?
I wanted to share how noise experts would proceed in addressing a skatepark, under the condition that we can perform a measurement at a similar installation. Without the ability to measure you have to rely on literature or “best practices”. Our approach would be
- to measure the noise pressure level of singular events in proximity
- to calculate the sound power level of those events
- then calculation of the sound propagation to the receiver points for each of the events
- then assessment of all events over time (exposure time)
We would do the modeling in dependence on the events
- singular impulse typically as a point source, could be an area source as well if several points are statistically spread over an area
- skateboards in motion are to be modeled as a line source
- statistically spread journeys of skateboards in an area modeled as an area source
For the calculation of the sound power level of all events you could decide to do a measurement at a greater distances, e.g. 30m over a period of e.g. 30 minutes. However, the distance (e.g. 30 meters) has to be greater than the expansion of the skateboard area. It is also assumed that the receiver point is sufficiently far away from the skateboard area. If all is given then before mentioned approach is a very good approximation of the to be expected noise levels.
5. I sometimes fail to place objects into a 3D terrain, can the camera position help?
When starting to digitize, typically with a corner point of an object, it is important that this point is correctly placed on the 3D terrain. Our recommendation:
always position Camara in top position
This can be achieved by going in SetchUp to Camera → Standard Viewes → Top. After the object has been positioned then you can check the correctness with typical SketchUp, e.g. orbit tools
6. How can I improve my presentation with animation?
SketchUp has numerous ways to improve the presentation of your noise map results, the most straight forward ones are as follows:
- export the noise map as an image into a .png file which can then be imported into a variety of office tools for further presentation. Please proceed as follows: File → Export → 2D Graphic …example:
- you may want to create scenes (snapshots) of various views to the model, which can then be exported into an Animation for automatic display at a customer site. Animation works as following
- after having completed the model and the noise map has been calculated, go ahead as follows
- first select the scenes tray which allows creation of scenes Window → Default Trays → Scenes
- then define the first scene in Sketchup by hitting the “+” sign in the scenes tray. A first scene is being created. At the same time a scenes tab is displayed in the command line. You can toggle on and off by selecting View → Scene → Tab
- Then “play” with your model and go adding more scenes by pressing the “+” after having moved to another “nice picture”
- When all scenes have been captured proceed exporting the presentation by choosing File → Export → Animation → Video
- As a result you will have a excellent presentation for working with your client.
Eventually, the Video will look like
7. I may have problems with my model, how can I “clean-up” the acoustic objects in my model?
noise3D offers a check and cleaning routine which allows you to verify that all acoustic objects created by noise3D are well positioned on the respective SketchUp layers, and also that the unique noise3D layers (those ending with _KS) do not include any incorrect data. The routine allows you to trace those “errors” and helps elimination. Please select:
»Extensions → noise3D → Help → Cleaning«
The cleaning routine will now enable the check of your model for consistency.
During the digitization of buildings, screens or other objects you may have interrupted the process, with regard to noise sources you may have overseen that octave spectra need to be added, etc. In any such cases noise3D may not be able to correctly execute the calculation. Therefore, with this routine you will be able to check your model for consistency and eliminate or correct elements with deficiencies. The presentation is similar to the Display Info function of noise3D.
Any defects should be worked on before proceeding with noise calculations.
noise3D will also trigger this routine automatically before submitting data to the calculation engine. Therefore, before mentioned may be required as well at that time to ensure quality input in the calculation process.
The following window displays a possible error screen:
You will either receive an error screen or the system will return to the previous screen without response. In that latter case you should be fine with your model. Otherwise, try to work on the issue or contact the support team.
8. How to copy acoustic objects from one into another model
Basically, you can Copy and Paste acoustic objects using the same CTRL+C and CTRL+V short cuts as in many other applications. Alternatively, in SketchUp select EDIT and COPY, later EDIT and PASTE.Step-by-step instruction:
- open two instances of SketchUp on your PC (will also work with only one instance, however, with two it is a bit easier to handle)
- open the first model you have in one SketchUp instance, open the target model in the other instance
- select those objects you intend to copy. Every element needs to be selected (i.e. keep the CNTR key pressed and click the elements chosen with the left mouse tab. If you have a source on a wall of the building then both, source and building have to be selected)
- select EDIT and COPY which moves the selection into the clipboard
- goto the target model, select EDIT and PAST and then position the pointer to the place you want to have the model drop in
- Eventually, you can then do further manipulation in the target model.
9. Noise Sources with Single Power Level
How to work with noise sources of which you have a single power level only? This is a special case you may face, however, is covered by ISO 9613 and noise3D online. The following is a step-by-step introduction.
- Commence with SketchUP as normal
- Include a Point Source where needed
- Right click and select Edit Acoustic
- Insert the given power level in frequency 500Hz, all other frequency levels are to be set 0. You may put the power level into a different field in case you have some information about the „heaviest“ frequency, however, only one field must be filled.
- In the project setup screen Plugins –>noise3D online-> Project Setup in tab General Setup –> Extended View please click field Agr ISO 9613-2 (10), this will initiate a simplified calculation
- If you proceed this way then noise3D online will calculate the exact noise leveles according to ISO 9613
10. Can I exclude acustic objects from the calculation process?
Acoustic Objects (Sources, Screens, Buildings, Bridges, Foilage and Land Use) can be excluded from noise3D calculations by Hiding the objects in SketchUp. Please proceed as follows:
in SketchUp select the acoustic object (use select function and just click on the object)
right click and select Hide
The object dissapears from the SketchUp scenario and will not be considered in noise3D calculations. In order to bring the object back into the model please proceed as follows:
– select View and Hidden Geometry
– right click the object and choose Unhide
Now the object will be included again in the noise3D calculation.
11. Does noise3D use linear or A-weighted Spectra?
noise3D is using A- weighted spectra dB(A). This is because of the wide use and since A-weighted levels typically have to be used at immission points. In all reporting and noise maps you will always see A-weighted levels. That is also the reason why the application does not support any conversion of linear to A-weighted or vice versa.
In case you have only linear spectra, then you can develop A-weighted levels by using the noise3D spectra tool box, please proceed to http://noise3d.com/wordpress/noise-calculation-introduction-2/ for that purpose
Please note: In case you do input linear spectra into noise3D then all results will be linear as well, even when noise3D says db(A) !
12. For which noise sources can I use Reference Distance?
The input of a value into the field Reference Distance in Edit Acoustic makes sense only for point sources, since the sound power level of a source can be calculated from the pressure level and reference distance only for point sources. For line sources or area sources such calculation cannot be performed correctly, and therefore, for any such sources you have to measure the sound power level from very close to the sources.
13. How does noise3D calculate the sound power level of a noise sources?
The user of noise3D determines by his or her input in Edit Acoustic, how noise3D calculates the sound power level of a sources.
Case A. A sound power level Lw of the sources is available.
In this case no further input is required. However, following parameters can be used:
- Num.Add. (day/night)
Num.Add. This is a deliberate correction. For this there are many applications in practise, e.g. the same spectrum is used for day and night, however, the source is more intense during the day. In that case you can enter a correction value into Num.Add.D .
Count. A sound power level Lw has been entered, however, there are several same sources at a certain location, e.g. there are 10 trucks going on a road lane. In that case please enter the number of equal sources into the field Count.
Case B. You have a measured sound pressure level Lp of the sources.
By entering the following fields the user of noise3D controls how the sound power level Lw is being calculated.
Example 1: You have measured at 10 cm outside in front of a window. In that case the size of the window F has to be entered into the field Count/Area eingegeben werden. noise 3D calculates Lw from the measured noise pressure level Lp as follows:
Note: the measured value in front of the window may be too high because of pfysical effects. It may be required to also enter a correction value into the field Num.Add. , in practice this will be -2 dB, in case the measurement was close (ca. 10 cm) in front of a larger area).
Example 2: You have measured a level inside of a building. In this case the size of the window F has to be entered in the field Count/Area as well. Then please select the noise absorption spectrum of the window thru the tab R-Spectrum. That spectrum can be entered or selected from your database. Then also click the field Use R-Spectrum and enter the correction value Cd, possible values are 0, 3, 5 or 6. Please also see the manual for a deeper discussion of this topic. noise 3D calculates the sound power level Lw from the measured sound pressure level Lp and the sound absorption R as follows:
Case C: You have measured a sound pressure level within a building, however, there is an open window or door. Please proceed as described above, but all octave spectra of the R spectrum have to be 0 in this case.
More details are described in the noise3D user manual.
The approach of noise3D allows the user of the application to specify pretty easily and straightforward how the calculation has to happen. This approach is much proven in practise.
14. I receive an error message in DISPLAY INFO, what can I do?
DISPLAY INFO is provided to display the information about all acoustic objects in your model. It assumes that the objects have been setup correctly with a minimum set of information, e.g. by adding the required spectrum data for a source by going into EDIT ACOUSTIC. In case this required input has not been provided you may receive the following display:
It is still possible to proceed, however, the display may well miss some of the objects you have placed in the model. The correct next step is to review your model, identify any objects that have not been setup properly and add the required information for those objects. The error message will then disappear.
15. AREA Source and PARKING LOT display a strange shape, what’s wrong?
When the area source or parking lot is “fit to terrain = True” and you have digitized a non-trivial shape then you may experience a slighly incorrect colored shape. This is due to how noise3D is painting in 3D mode and is not an issue for the calculation.
You can see in above picture how an area source has been painted slightly incorrect. It is important to note that noise3D does not run pictures through the calculation engine but the position data of the objects. Although the picture looks incorrect noise3D feeds the correct position data of the corners into the engine.
In the development of the 3D imaging we had to compromise and avoid overly complicated painting algorithms which had significantly impacted on the performance of the application.
In case you want to avoid a situation like above then please cut the area source into two or three pieces and provide the identical acoustic data for each of the pieces which resolves the display problem.