This paper connects design creativity to engineering activities as means for smooth implementation of creative concepts. It applies C-K design theory and the IDER-innovation model as lenses to investigate three case studies. The results point to engineering activities as operators to transform the undecidable concepts in the C-space to objects with a logical status in the K-space. Engineering (E) knowledge as validated objects in the K-space supports the transformation process. If existing E-knowledge is sufficient, then this resembles single loop learning. If concepts in the C-space are too different from earlier concepts, then new E-knowledge needs to be developed which resembles double loop learning. The research for developing new E-knowledge unfolds in a similar fashion. Tentative theoretical insights in the C-space are 'engineered' by validated research methods from the K-space. Further research needs to address the complexity of real-life socio-interactive situations. The paper shows that the engineering act in a heterogeneous manner is at least of equal importance for innovation as the creative design act.