ACOUSTIC ANALYSIS - Designing Raked Audience Seating
Creating Construction Lines
In this tutorial you will work through the process of creating
a simple raked audienceseating
- Open Raked Seating.eco
from the Tutorial Files directory located in your main ECOTECT Install directory.
There are three zones in this model; Auditorium, Construction Lines, and the
default Outside zone.
- Firstly we need to create a vertical construction line (about 5000mm
high) at the front of the stage in the middle.
To do this, make sure the Construction Lines zone is current. Then
using the Line
tool, snap to the Mid-point of the base of the stage at the front.
Left click to insert the first node, then with the Control key
pressed down (constrains the cursor to the Z axis only) drag the mouse upwards
until a height of around 5000 is reached.
Left click again to accept the second node, then hit the Escape
key to finish the line.
- Now that we have the first vertical construction line we can array them
in the X direction, with a gap of around 1000mm, to mark the distance between
the rows of seating.
The easiest way to do this is to use the Object Transformation panel.
||Make sure the vertical line is selected, then enter values
similar to the ones shown to the left.
Once entered, click the Apply button.
The final array should produce one row of 17 vertical lines.
- Next draw a line between the start of the sound source and the bottom
of the 10th line. This is best done in Front view (F7).
This line is going to be the basis of our equal-sight-angle lines.
We're using the 10th row back as the starting point for our rake, as the front
seats will have good sight lines anyway.
- Now, extend the line just created and the rear-most vertical line so
that they meet .
Select both the lines, then from the Modify menu choose the Intersect
Two Lines item.
- Finally you need to rotate the angled line by 1° about the speaker
One of the easiest ways to do this is to; select the line, then select the
Object Transformation panel. From the panel choose the Rotate -
Axis from the Transform Type pull-down list, enter a Y Angle
of 1° and an array quantity of about 20, then click the
Create Array button.
Starting the Seating Profile
- The next step is to zoom in to the first set of intersection points
between the two sets of lines, and start tracing a new line where they intersect.
Make sure snaps are set to Intersections, and that the Auditorium zone is
As this line is the start of the seating profile it needs to be on a zone
other than Construction Lines.
- Continue this line through each of the vertical lines, all the way to
the back of the audience plane.
- Zoom out (Ctrl + F) and turn off the Construction Lines zone.
The seating profile should look similar to the one shown below.
Creating Horizontal Steps
- Zoom in on first raised node on the seating profile, double-click the
line (Node mode) and select the first raised node.
If the height of this node is less than 100mm then it needs to be dropped
down to Z = 0, as it's not high enough to make a full step from.
The easiest way to do this, is to enter 0 in the Z Position of the
Selection Information panel, then click the Apply Changes button
at the bottom of the panel.
- Moving onto the next node... Still in Node mode, select the Add Node
With Align snaps on (and preferably most of the other snaps off), left
click the segment between the last node and the first raised node. Align the
new node in the X and Y axis (as shown below), and left click again to accept
the new nodes position.
- Continue on adding and aligning new nodes, until the entire seating
profile is modified from curved to stepped.
The final curve should look like the one shown below. Given the step size
towards the rear, you will probably have to model some additional steps in
the aisles later on.
- Before going on to the next section, double check the steps in perspective
If your line looks like the one shown above, you will need to shift the new
nodes in-line with the old.
Again, the easiest way to do this is to select the nodes and use the Selection
Information panel, and enter 4500 in the Y Position input box,
as you did in step 1 of this section. Don't forget to click the Apply Changes
button at the bottom of the panel.
Extruding a Line
Now that we have created the steps, we need to extrude them the full width
of the auditorium.
- With the line still selected and in Object mode, type 9000 in
the Y Extrusion Vector box of the Selection Information panel.
Then click the Apply Changes button at the bottom of the panel.
- With the original object (now the parent object to all the extruded
planes) still selected, use the Move
tool to move the seating so that it lines up with the edge of the floor
plane, -4500 in the Y axis.
Cutting and Shaping the Seating
It may not be desirable to have a rectangular seating area. In which case
you can use a cutting plane to trim / extend the seating any way you want.
As an example, we are going to cut it at an angle to the stage.
- In Plan view, draw a Partition ,
from the speaker source point towards the rear of the seating at an angle
of about 20°.
- Assign the partition as a Cutting Plane (Ctrl+Q). A small arrow should
appear in the centre of the object.
Deselect the partition and instead select all of the seating planes.
Once the seats are selected, press Ctrl+E to extend the selection to
the Cutting Plane.
- After one side has been extended, the same needs to be done for the
Either mirror the existing Cutting Plane about the centre, or create a new
plane at -20°.
Then repeat step 2, and when finished delete the one / two partition objects.
The final seating should look similar to the image shown below.