You must be able to clearly communicate the compliant viewing area to the Architect and other stakeholders during the design phases of any project. Whilst all modern construction will be modelled in Revit or an equivalent package, speed and accuracy of communication are the key and you will normally be marking-up the latest architectural layouts.
Drawing the compliant viewing area seems daunting at first, but after a bit of practice you should be regularly preparing accurate, informative markups in just a couple of minutes – using nothing more complex than your favourite PDF tool.
This section demonstrates a simple strategy for markup using Bluebeam which is rapidly becoming the default PDF tool for engineering. For simplicity this exercise is drawn over a blank sheet rather than a busy architectural layout.
As with all design, accuracy is important – but don’t stress over a few mm! No two heads will usually be in exactly the same position, and even 100mm at FV is within expected head movement range.
You need to complete your design calculations first – for this example, we’ve calculates as follows:
- 120” projected image at 16:9 aspect ratio
- Bottom of image = 1400mm affl (i.e.: Image Offset = 200)
- Element height (%EH) = 3/0%
- FV = 8970
- CV = 1.732 x (1495 + 200) = 3109
- CVROW = 6 x (1695 + 200) = 7515
|1||Draw the screen to scale and in its expected position|
|2||Using the ANGLE tool from the Measurements tool group, add the 60° horizontal viewing limits|
|3||Measure CV from front of screen and add a horizontal CV line|
(Cross check your work by measuring CVROW – if it is incorrect, check whether you correctly calculated including Image Offset)
|4||Using the Bluebeam CENTRE RADIUS tool (Measurements tool group), draw circles with radius of FV. Position a circle at each end of your screen.|
|5||Select Bluebeam’s POLYGON tool and draw a closed line following this path|
· CV between its intersections with the horizontal limit lines
· Along horizontal limit line to the intersection with the inner arc
· To the intersection of the two circles
· To the intersection of the inner arc and the horizontal limit line; and
· Back to the intersection of the CV and horizontal limit lines
|6||Right click on one of the FV lines and select CONVERT TO ARC. Manipulate the handles to shape the arc to conform to the inner circle. Repeat for the second FV line|
|7||Delete all construction lines – what remains is your compliant viewing area.|
|But what about a dual-image room? Simple.|
|8||Model the two screens individually|
|9||Add a second polygon to define the overall compliant viewing area. If all screens display the same image, the compliant area is as below|
|10||If each screen is independently routable, only the common area (union of the discrete compliant viewing areas) is valid|