Recent approaches to providing users with more natural methods of interacting with virtual environment applications have shown that more than one mode of input can be both beneficial and intuitive as a communication medium between humans and computer applications. Although there are many different modes that could be used in these applications, hand gestures and speech appear to be two of the most logical since users will typically be in environments that will have them immersed in a virtual world with limited access to traditional input devices such as the keyboard or mouse. MSVT (Multimodal Scientific Visualization Tool) is a prototype application for visualizing fluid flow around a dataset. MSVT uses a multimodal interface which combines whole-hand and voice input to allow users to visualize and interact with the dataset in a natural manner.