View out criteria
View to the outside provides visual contact with the surrounding, so as to supply information for orientation, to experience the weather changes and to follow with the time over the day.
The view quality depends on
- the size of the windows and the distance from the reference point to the window which together gives width of the view,
- the outside distance of the view (distance from the inner surface of view opening to opposite major obstructions located in front of the opening)
- the number of layers and
- the quality of the environmental information of the view.
According to EN17037:
- “The criteria for view out concerns the utilized area” section 5.2.2
- “View to the outside should be assessed from selected reference points corresponding to where people are located within the utilize area”. section 5.2.1.
- “Three levels of view out, horizontal sight angle, the distance to outside view, and the number of layers are assessed from reference positions.” section A.3
And regarding the required % of the utilized area for Horizontal Sight Angle and Distance Out C.3 states that
The reference points can be at any potential location within the utilized area of the space.
Implying that 100% of the utilized area is required for the criterion to pass. This parameter can be set to a different value within the software. Refer to the below section on where to set this.
The Criteria for Minimum View Out:
- View Windows should have minimum dimensions (Width x Height = 1m x 1.25 m)
- For all reference points on the utilized area, Distance to Outside elements should be larger than minimum value (6 m)
- For all reference points on the utilized area, view windows should have a Horizontal Sight Angle higher than the minimum value (14 °)
- A minimum fraction (75%) of the utilized area, the users of the space should be able to see at least the landscape layer.
Indicative points of the projection should be at points in the room where people are actually sitting (eyelevel 1.2 m over the floor) or standing (eyelevel 1.7 m over the floor).
View out assessment
Assessment of the view outwards from a given position
Outside Distance is calculated across the utilized area for each reference point. The rating is done as follow for each reference point:
The averaged distances to the outside obstructions are calculated for each of the three bands (minimum, medium, high) separately. It is the average of all distances to the outside obstructions that fall within a specific radius(correspond to the band). This is considered as valid only if the obstructions within the band obscure the view more than a specified threshold (e.g. 10% threshold in above figure). Otherwise the band is regarded as having no obstructed view and no shortest distance is recorded.
A full sphere fisheye view is rendered for each reference point to accumulate distances on each band from all the openings.
The Settings for View calculation can be set from Project Settings > Assessment Criteria tab:
The ViewTest dialog (MBSViewTest command) can be used to visualize the three tests.
The image on the right shows outside distances from a point inside a room. The outside distance is calculated across the utilized area for each reference point. The rating is done as follow for each reference point:
- Distances to landscape layer is used. Distance to Sky and Ground are not used for outside distance to view.
- The average distances to the outside obstructions are calculated for each of the three bands (minimum, medium, high) separately.
- It is the average of all distances to the outside obstructions that fall within a specific radius (correspond to the band).
- This is considered as valid only if the obstructions within the band obscure the view more than a specified threshold (e.g. 10% threshold in above figure). Otherwise the band is regarded as having no obstructed view and no shortest distance is recorded.
- For example, In the image shown, the shortest distance to view is taken from the 0–<6 band as the % of view in that is more than the 10% threshold. If the % of view is less than 10% then the shortest distance will be checked in the 6- < 20 band and so on.
The image on the right shows the falsecolor map for distance to view and other visible layers. Sky, Ground, Inside Room, Beyond lens and various distance band are allocated various colors to distinguish the objects seen from the reference point.
The percentage of visible layers seen (Sky, Ground and Landscape) are shown on the right hand side. The average shortest distance and horizontal sight angle are shown as well.
The chart shows the % of view taken by distance to view in each band.
