[FAQ] Does the VTO and the size guarantee work with children?

The VTO module is designed to work with everybody, both adults and children.

However, in order to scale and position virtual frames correctly, the VTO module requires a PD value for the user. Without any specified information, the VTO module is set by default with an average adult PD value (of 63mm).

In order to provide the best user experience possible, we recommend setting or allowing the user to set a precise PD value (see our How-to guide to Configure the PD).

This recommendation is especially important if you target children as their PD will be far from the default value and may vary wildly from one child to the other.

When providing the VTO module for frames made for children, asking the user to set a precise PD value should be mandatory. Offering age groups with average values can also be a simpler solution for the user (see this example).