Determining voxelsize
In order to determine the voxelsize that our growth simulation will work with, a case study has been done. The starting point to generate a workable voxel size is the sizing of the stairs. Because of the functionality and the limited flexibility this stairsize is fundamental in use of the building and therefore functions as the main guide towards a useful gridsize.
Starting points
Stairs Free space residences +/- 270 cm 270 cm= 1 height?
270/6= 45 270/9= 30 270/5= 54 270/3= 90 270/2= 135
Stair dimensions from ‘’menselijke maat’’ : stair angle between 30 and 41 degrees Stair width for moving in 2 directions, minimum 120 cm rise 14cm advised, minimum of 8cm tread with minimum 25 cm 38 degrees ideal size for stairs?
Bouwbesluit minimum tread with 22cm maximum rise 0,188cm source
Corridor Main hallways: at least 1,5 metre in width support hallways: at least 1,2 metre in width source
Stair sizes
| Option | Rise | Tread width | Length stairs | Width staircase |
|---|---|---|---|---|
| Option 1 | Rise= 18cm (3x6) 270/18 = 15 steps | 30cm (5x6) | 15x30 = 450cm | 120cm (20x6) |
| Option 2 | 18cm (2x9) 270/18 = 15 steps | 27cm (3x9) | 15x27= 405 | 126 cm(14x9) |
| Option 3 | 18cm (3x6): 306/18 = 17 steps | 30cm (5x6) | 17x30 = 510cm | 120cm (20x6) |
| Option 4 | 18cm (2x9) 306/18 = 17 steps | 27cm (3x9) | 18x27= 486cm | 126 cm(14x9) |
| Option 5 | 18cm (3x6) 306/18 = 17 steps | 24cm (4x6) | 17x24 = 408cm | 120cm (20x6) |
For further research we will only use option 3,4 & 5. Since after discussion we decided to enlarge the floor height.
First approach
Y dimension
| Option | Based on stair option | x/y/z sizes | Comment |
|---|---|---|---|
| Option 1 | Option 3 | 120 / 510 / 306 | 510 is quite a big size, but there’s no division possible which leads to an integer multitude of 6. So this will not be a good voxel size. |
| Option 2 | Option 4 | 126 / 486 / 306 -> 126 / 162 / 306 | To make it fitting for human dimensions let’s divide the the y value by 3. The stairs which we calculated earlier will now be 3 voxels. |
| Option 3 | Option 5 | 120 / 408 / 306 -> 120 / 102 / 306 | The previous voxels will be sufficient for a building with the same height everywhere, but the z value is too big to differ in height through the building. |
Z dimension
| Option | Size | Ratio |
|---|---|---|
| Option 1: based on y dimension option 2 and stairs option 4 divisible by 9 | 126/162/306 divide the z value with 2-> 126/162/153 the staircase will now be 3x2 voxels | ratio 1 to 1.3 |
| Option 2: based on y dimension option 3 and stairs option 5 divisible by 6 | 120/204/102 divide the z value with 3->The staircase will now be 2x3 voxels | ratio 1 to 1.7 |
| Option 3: based on y dimension option 3 and stairs option 5 divisible by 6 | 120/102/306 divide the z value with 3-> the staircase will now be 4x3 | ratio 1 to 0,85 |
Definitive approach
Since a different x and y value affected the modularity of the building and spaces were otherwise forced into one particular direction. We have decided after consultation with our tutors to take the same dimension for the x and y value of the voxel.
For the definitive approach towards the voxel size we will use the option for stair dimensions we previously used, since the size was thoroughly thought about in the first approach. Apart from this, as a project group we decided it would be a pragmatic approach to decide our tartan grid based on the thickness of the support structure the building will be made of, to make it fit into the tartan grid.
For this, we made a rough estimation of the area of our building through the Program of Requirements, and how this relates to the available area for our building (obtained through measurements in ArcGIS), we came to a rough estimate of 3 stories, if the available area is maximised, in other words: if all the spaces are summed up.
Since we have to take into account the varying height in the building, we decided to look at surrounding buildings in the area and the width of the streets and decided upon a maximum of 10 stories high. We estimated that we would need a SHS-HF-300 profile for this height. We chose this profile because it has the same x as y value and based our voxel grid on this.
Although these dimensions (300x300) are workable, the size is really small and not really algorithm friendly because the building would consist of too many voxels because of the building site's size.
So let’s take the 300x300 voxels as our meso voxels for the tartan grid.
If we go back to the stair dimensions which were previously researched and have chosen the following can be said: Rise= 18cm (3x6), 306/18 = 17 steps, tread width= 30cm (5x6), length stairs= 17x30 = 510cm, width staircase= 120cm (20x6)
With a stair width of 120cm we could make our voxel size based on 120cm+ meso voxel. But to be on the safe side, and taken into account the railings of the stairs it’s better to take an extra meso voxel for the voxel size. So the voxel size will be 150cm + mesovoxel = 180cm.
The tartan grid is the place where the structural profiles or the walls can come.
