Overview
The aim of this app is to dynamically model the relationship between
room size, aperture layout and the spatial distribution of internal daylighting. To make it
fun to play with, I have tried to ensure that the app and its calculations are as fast and
interactive as possible so that changes to the room or its apertures update the daylighting
in close to real time, even on a tablet or phone.
To change the size of the room, simply select any of its bounding surfaces
and then drag the appropriate arrow in the direction you want. To adjust an aperture, again simply
select it by clicking or tapping it and then drag any of the manipulator arrows. The manipulator
in the center of the aperture allows you to change its position. Whilst apertures are prevented from
overlapping, you can still drag them into any area where they will fit, even within adjacent walls.
You can click or tap on any value in a dimension line to display a simple
editor that lets you directly enter numeric data. Clicking or tapping in the ROOM INFORMATION
panel on the left will also display an editor for numerically adjusting the room size.
Daylight Calculation Method
The daylight calculations here use the split-flux method developed
by the Building Research Establishment (BRE) in the UK. This involved converting all the required
protractors and nomograms to high-resolution look-up tables. To validate this approach, I have done
extensive comparisons of both the absolute daylight factors generated in this model with those of
the same model in Radiance from LBNL, as well as the magnitude of relative changes in value when
apertures are enlarged/reduced, the room size changed or reflectance values varied. As the room is
relatively simple and always convex, and the apertures are rectangular without any complex
shading or light reflection systems, there is pretty close correlation with Radiance results.
A future version of this app will allow you to remotely render the current
model in Radiance and then import the results for your own visual comparison. I am currently
working on all the back-end systems to make this happen.
Points of Interest
At the moment all the daylight calculations are being done in Javascript,
which is still blazingly fast. However, I do have a GPU-based version which
is even faster. But, given that there is so much else going on when you interact with the model
(especially when contours are displayed and multiple apertures are being checked for overlaps),
it turns out that the daylighting calculations are only a relatively small component compared to
the tesselation and mesh regeneration process. Thus the speed increase due to using the GPU is
not actually that noticeable.
© Dr. Andrew J. Marsh, 2018.
View Manipulation
You can interactively adjust the 3D view of the model using a mouse,
pen or stylus, or by touch on a tablet or phone.
You can also use the items in the 3D View Settings popup.
- Rotation:
- Drag with the left/right button or a single finger,
or use the arrow keys.
- Panning:
- Drag with the middle button or two/three fingers,
or use the A and D keys.
- Zooming:
- Use the scroll wheel or pinch with two fingers,
or use the W and S keys.
NOTE: You can use the Shift and Ctrl/Meta keys to adjust the increment
of each scroll event or key press.
Keyboard Modifiers
The Shift and Ctrl/Meta keys are used pretty extensively
to modify interactive data entry. This applies to all increment buttons, scroll wheel motion,
slider controls and input elements.
- Shift Key:
- Increases input to larger values, usually by ten times or significantly larger increments
such as 1 month for dates and 1 hour for times.
- Ctrl or Meta Key:
- Decreases input to smaller values, usually by one tenth or the smallest reasonable increment
such as 1 day for dates or 1 minute for times.
NOTE: You can use the scroll wheel to edit a data value when hovering over any slider,
numeric input or even table rows that indicate their editibility.
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