We developed a new method employing automated facial emotion detection software and cursor tracking to link designer emotions and corresponding designer activities while using synchronous collaborative Computer-Aided Design (CAD) software. We applied this method via an experiment with nine participants, each working with the same CAD platform, and assigned a CAD task in one of two distinct working styles: single participants working by themselves and paired participants working together. We analyzed and compared trends in emotion for these two working styles. Pairs experienced, on average per person, higher levels of emotion (measured as joy, sadness, anger, contempt, fear and surprise) than individuals. We linked occurrences of each emotional response to their antecedent activities in the CAD environment (navigating the model tree, sketching, making selections in the feature menu, and communicating). Using a logistic regression analysis, we revealed statistically significant trends linking emotions and antecedent CAD events, and we found that some emotions are more likely to occur with certain designer actions in the CAD software. The method and conclusions presented in this paper allow us to better understand designer emotions in traditional and collaborative CAD, which links to insight related to designer satisfaction, creativity, performance and other outcomes increasingly valued by engineering designers and managers in virtually collaborative environments.