How to interpret a linear tolerance stack
Tolerance Lab exposes each stack member as a nominal value, upper/lower deviation, and signed direction. The worst-case result sums physical limits without assuming a production distribution; the RSS view provides a statistical estimate for independent contributors.
Worst-case
Use it to check assembly limits and the clearance/interference interval that must be guaranteed.
RSS
An early-design estimate for independent, approximately normal contributors; it does not replace process capability evidence.
Sensitivity
Highlights the members with the largest variance contribution so the tolerance budget can be improved deliberately.