Dimensional distortion, cosmetic distortion issues can arise during heating and cooling in the paint shop processing of car bodies. A car body can be in perfect cosmetic condition as it leaves the BIW facility, yet develop distortion defects during painting.Traditionally such issues have only been detectable on new car body designs by building and painting prototypes of a new design. The timing of such activities, by their very nature, mean that precious little time is available to address these issues by design changes in today's condensed new vehicle programmes. The result is often a vehicle entering production with partial resolution of an issue, accompanied by on-going product rework and rectification activities throughout the lifecycle of the product.This created the need for developing a CAE simulation tool which could predict these issues very early during the virtual CAE build phases of a vehicle program itself. The development work of the CAE simulation tool involved the use of FE tools coupled with measurements and physical tests in a paint shop oven.Good predicted baking temperature correlation was achieved with the method developed, together with the ability to accurately predict transient distortion modes occurring at any selected area of a car body during its paint baking process inside the oven.This newly developed paint bake simulation CAE tool will permit early programme detection of thermal distortion issues and support the implementation of distortion proof design strategies on all present and future vehicle programmes.