Selecting dimensions for Design Percentiles - Pro version

You can use the Design Percentile facility in two main ways:

1. To calculate the percentage of your User Group that will fit the whole design, if you use the current Dimension percentiles.

2. Conversely, to calculate the Dimension percentile that must be set, in order to achieve a target Design Percentile.

For most design purposes, this latter function is the more important, since it will correctly specify the main output of PeopleSize for your project - the individual dimensions which will make sure that your design fits the required percentage of people overall. This facility is called the AUTO function, which you can also access via the Settings dialog.

In addition, you can calculate partial accommodations:

Either the Small or Large Design Percentile if you use the current Dimension percentile.

The percentage of users who are smaller in all of two or more dimensions, when these fit PART of the design rather than all of it.

For any of these functions, you have to identify the dimensions which will determine whether large and small people will fit the design. Some body dimensions can be important for either large or small user fit (such as eye height, lumbar curve height), so the selection process is not automatic, you need to think it through for your design.

For both user sizes, you will probably need to sketch or visualise the design being used:

Smallest User:

Make the user very small and identify the body part sizes which prevent a good fit. The problems are most likely to be a lack of reach, when body parts have to fit outside or up to design parts. Examples include seat height, seat cushion length, shelf height, seat-to-control distances etc. This example shows how the key dimensions for a workstation are knee height, buttock to back-of-knee length, elbow height and lumbar height.

Largest User:

Make the user very large, and identify the body part sizes which prevent a good fit. The problems are most likely to be a lack of clearance, when body parts have to fit inside design parts. Examples include headroom, knee-room, elbow-room, thigh clearance etc. This example shows how a sketch of a large user at a computer workstation reveals that key Large User dimensions are: eye height, lumbar height, buttock-knee length, knee height and elbow height.

Note that even when the same dimension is relevant to both Large and Small users, it tends to be for different reasons. For example, elbow height may be too high for fixed armrests among Large users, or too low for the desk and keyboard among Small users.

As we have done here, you can use PeopleSize illustrations to help you, by Exporting them. Then you can draw your design on top, either in a computer program or print and sketch on paper.