Vertical illuminance

questions regarding the handling of DIALux evo. (features, tools, options, settings)
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Vertical illuminance

Post by dodos880125 » Wed Jul 22, 2020 9:31 am

I'm doing some calculations in DIALux.
I need to calculate vertical plane at eye level(1.2m) of the occupant.
Is that the same as vertical illuminance in DIALux?
What is the difference between vertical illuminance and perpendicular illuminance?
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Joined: Wed Mar 07, 2012 3:07 pm

Re: Vertical illuminance

Post by Csuleiman » Wed Jul 22, 2020 12:20 pm

Hello dodos880125,

We would like to give you some general information about the calculation surface and its parameters:

The workplane is implemented according to the standard EN12464-1. You cannot change the parameters of a workplane as they always should be adaptive calculated. So a grid of some points are not defined in this way. It is not possible to change the workplane to a calculation surface.

While a certain grid is used for the different measured values it can always be that some minimum or maximum is between those two points. To pretend this you can choose this parameter “perpendicular illuminance adaptive” for calculating on a surface. Then the value to be determined is not defined on a fixed grid but dynamically in the positions where relevant changes take place.
So, adaptive means a dynamic adaptation of the measuring grid. The number of measuring points is dynamically adjusted in such a way that the minimum and maximum values of the illumination intensity are detected as far as possible. This is useful if there are large differences in the illuminances on the surface. The set number of measuring points therefore only affects the other parameters.
The perpendicular calculation parameter is always perpendicular to the surface, regardless of how the surface is positioned. If the surface is vertical, then both parameters are identical horizontally and perpendicular. As soon as the surface is inclined, however, this is no longer the case.

Under the following link you will find some information about the calculation objects and their parameters: ... ion-object

Best regards,
DIAL Support Team

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Joined: Thu May 07, 2020 4:39 pm

Re: Vertical illuminance

Post by dodos880125 » Wed Jul 22, 2020 1:39 pm

I'm very sorry that I can't understand the definition.
Can we just make things simple?
If I want to calculate the illuminance on the vertical plane at the occupant’s line of sight (1.2m) which function
I can use?
Is it vertical illuminance?
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And what is height offset and rotation do on calculation?
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Joined: Tue Jun 02, 2015 7:40 am

Re: Vertical illuminance

Post by LuHü » Fri Jul 24, 2020 9:39 am

Hello dodos,

in your case you can use the perpendicular and the vertical!
The only difference is the description of your calculation-surface in the documentation ("perpendicular" or "vertical").

To check the direction of your calculation:
Helpful is here the 3D-view. After clicking on the calculation-surface you see a little orange arrow which shows your calculation direction.

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vertical.jpg (36.22 KiB) Viewed 3261 times
horizontal.jpg (34.85 KiB) Viewed 3261 times
Lukas Hünting

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Joined: Thu May 07, 2020 4:39 pm

Re: Vertical illuminance

Post by dodos880125 » Sat Jul 25, 2020 12:14 pm

Hello Lukas,

Thank you so much!
I totally understand now.



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