  Modern cars exist in an vast number of variants. Thus, variability has to be
dealt with in all phases of the development process, in particular during
model-based development of software-intensive functionality using
Matlab/Simulink. Currently, variability is often encoded within a functional
model leading to so called 150%-models which easily become very complex and do
not scale for larger product lines. To counter these problems, we propose a
modular variability modeling approach for Matlab/Simulink based on the concept
of delta modeling [8, 9, 24]. A functional variant is described by a delta
encapsulating a set of modifications. A sequence of deltas can be applied to a
core product to derive the desired variant. We present a prototypical
implementation, which is integrated into Matlab/Simulink and offers graphical
editing of delta models.
