Question about the size of the area

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Simon
Posts: 12
Joined: Wed Jan 06, 2021 7:32 am

Question about the size of the area

Post by Simon »

Hello, dear Envi-met team!
I'm a new one here and I have some questions about my future work with Envi-met. I want to investigate the impact of greenery in a central city area (a block). I want to make two scenarios - without vertical greenery and with VG. To avoid inaccuracies I expanded the area a bit as the street canyons could get in it (see attached file). The whole rectangle now is 170/202m. The highest building is 35m. I think that 3m resolution is ok (or 2 maybe for x and y). My questions are:
1. Do you think that this area will be OK
2. How many cells should I leave empty around the area regarding the height of the buildings?
3. Is it normal that every time I close spaces and open the file again, the digitizing picture is gone and have to load and adjust it again?

Thank you a lot in advance!
Attachments
Screenshot_2021-01-06 https www sofia-agk com.jpg

Tim
Posts: 2042
Joined: Mon May 15, 2017 3:46 pm

Re: Question about the size of the area

Post by Tim »

Hi Simon,

Welcome to ENVI-met!
The area looks absolutely fine. You probably also need the building information in the lower right corner, otherwise shadowing of the buildings (that are probably there in real life) does not take place in your simulation. You should leave around 30 m empty cells which would be 15 cells in the 2 m resolution... maybe 10 will be OK as well. Unfortunately, the bitmap is not saved in the INX, so yes it is normal that you have to load it again when opening Spaces.
You may consider to modify your work process: Georeference the picture in a GIS, digitize the buildings, surfaces, vegetation as shapefiles, load them into Monde, export them to ModellingLayer and then export the model area to an INX. It has the advantage that you can export the same model area in different resolutions (or different amounts of empty cells at the border) as often as you want without the need of digitizing everything again.

Best regards,
Tim

Simon
Posts: 12
Joined: Wed Jan 06, 2021 7:32 am

Re: Question about the size of the area

Post by Simon »

Thank you very much, Tim!

Best regards

Simon
Posts: 12
Joined: Wed Jan 06, 2021 7:32 am

Re: Question about the size of the area

Post by Simon »

And one more question:
As I don't use GIS, is there a way to export the drawing made in Autocad or Archicad?
I tester Monde, but the data is not enough for my work and need to be modeled.

Tim
Posts: 2042
Joined: Mon May 15, 2017 3:46 pm

Re: Question about the size of the area

Post by Tim »

Hi,

No, at the moment, you can only use shapefile as import to Monde.

Best regards,
Tim

Simon
Posts: 12
Joined: Wed Jan 06, 2021 7:32 am

Re: Question about the size of the area

Post by Simon »

Hello Tim,
I built buildings (all they are separated to ease the green roof positionning) and the surfaces and have some questions before I start to place the vegetation units etc.

1. What happens if we have a underground parking which is opened (without doors)? I think that the entrance of a underground level (and there should be 2 levels) should change the environmental microclimat near the building. How I have to handle this case?

2. I put some hedges and I wondered where is their with described (because at spaces every hedge is an entire cell - in my case 3m)? (as I didn't see it at the DBmanager)

3. Here attached is my entire area and its already mentioned sizes. Could you please check it out before I move on... and please give some advice if I did something wrong.

Thank you in advance
Attachments
scr.jpg
mpdel.jpg

Tim
Posts: 2042
Joined: Mon May 15, 2017 3:46 pm

Re: Question about the size of the area

Post by Tim »

Hi,

1. In reality, it definitely makes a difference. Digitizing that in your model however is quite tricky. You might give it a try with a building that has bottom values starting above ground level. Going below terrain level is of course not possible. I'd probably neglect it and would not digitize it in that detail.

2. The hedges are as wide as the grid cell. If a cell is 10x10 m and you digitized the cell as hedge, the 10x10 m cell is totally filled with LAD values of the hedge.

3. It looks fine!

Best regards,
Tim

Simon
Posts: 12
Joined: Wed Jan 06, 2021 7:32 am

Re: Question about the size of the area

Post by Simon »

Ok, what if I want to have 2m tall green srcreens on the plot borders (like green fence)?

An one more question about the period of simulation: is it possible to make it just for 1-2 hours period (for example 12-13h on 07.08.2001) on two scenarios to be compared with or without greening in order to shorten the calculation time ? Or the period have to be 24h ....is there a minimum to be accurate?

Tim
Posts: 2042
Joined: Mon May 15, 2017 3:46 pm

Re: Question about the size of the area

Post by Tim »

Hi,

If you have a vertical grid size that goes up to 2 m and the hedge has LAD layers up to the height of 2 m, you will receive a hedge that covers the cells up to the height of 2 m.

No, simulating only 1 or 2 hours is not recommend. The model (all materials etc) need some time to initialize. In general, the model is started with sunrise and is then simulated for at least 24 or 48 hours.

Best regards,
Tim

Simon
Posts: 12
Joined: Wed Jan 06, 2021 7:32 am

Re: Question about the size of the area

Post by Simon »

Hi Tim,
maybe I did't express myself clearly. I need to put green screens like those at the picture below. The problem is not at the height but the width - not more that 0,5m.
Unfortunately sigle walls can't be greened... any idea how to handle this case?
Attachments
Mobilane-Product-pagina-Kant-Klaar-Haag.jpg

Tim
Posts: 2042
Joined: Mon May 15, 2017 3:46 pm

Re: Question about the size of the area

Post by Tim »

Hi,

Ah, I see. No, there is no possibility to exactly digitize that. You will need to make a tradeoff as always needed in modelling. Simulating the whole model area in 0.5 m resolution to define the hedge accurately is definitely not a solution. I'd simply digitize a hedge there but with a lower LAD to match the greater air volume part instead of leaves in the cell.

Best regards,
Tim

Simon
Posts: 12
Joined: Wed Jan 06, 2021 7:32 am

Re: Question about the size of the area

Post by Simon »

Thak you, Tim for your help. I search and read topics not to bother you unnecessarily, but I still have questions.
The idea of my research is linked with my phd thesis about the vertical greenery at the urban environment. My first scenario is almost ready and I faced another obstacle:
1. telescoping should have be done ABOVE the highest building, but it is not. What king of problem will be that? The inspector tells me that I have to add more cells (see below). I already saved it in 3d and added invividual segments (roof greening)... that are lost after reconverting it in 2,5D concept design to change telescoping and when adding more cells the roof greening is lost too..
2. How the % factor of telescoping has to be set as perfect as possible?
3. Do the empty cells at border have to be covered (sealed) by alphalt ot to leave them 00? (as my default material is loamy soil)
4. Should I change the surface below the buildings or leave it as it is 00?
5. Will adding glass segments to the buildings extend the simulation time?
Attachments
3.jpg
2.jpg

Tim
Posts: 2042
Joined: Mon May 15, 2017 3:46 pm

Re: Question about the size of the area

Post by Tim »

Hi,

1. It is not a big deal if it starts shortly below the highest building. We recommend to start above to not stretch building cells and thus cast a larger (unrealistic shadow). Yes, when converting back to 2.5D, all 3D information about facades or greenery is lost.
2. 30 % is the maximum. I would try it with 20 % to not stretch them at maximum.
3. The empty cells at the border only mean that there should be no building (and less vegetation) to allow a free wind flow around and through the core model area. Surfaces need to be digitized accurately (with asphalt etc.).
4. You can leave it as it is, it does not matter below the buildings.
5. No, they don't extend the simulation time.

Best regards,
Tim

Simon
Posts: 12
Joined: Wed Jan 06, 2021 7:32 am

Re: Question about the size of the area

Post by Simon »

OK, so let me to be sure what your recommendations are:
1. back to 2,5D to extend the area
2. move telescoping to 20% and 45m
3. seal all surfaces at the extended area, because they are buildings and roads
4. repeat my roof greenning segments, glasses etc.
Is it ok?

Thank you
Best regrards

Tim
Posts: 2042
Joined: Mon May 15, 2017 3:46 pm

Re: Question about the size of the area

Post by Tim »

Hi,

Yes, that would be my suggestion.

Best regards,
Tim

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