December 22, 2003—Ergonomic Technologies Corporation (ETC) has released the results of their ergonomic comparison of two-handed and one-handed CAD working styles. The two-handing working style—using a mouse in one hand and a 3D motion controller in the other—showed considerable ergonomic advantages over the one-handed style of using a mouse and modifier keys. Actual physical measurements showed that hand motion activity was reduced by 64% and that average muscle output was 33% less using the two-handed approach. These physical measurements were further corroborated by the users’ perceptions in which all nine body comfort factors were rated higher with the two-handed working style.
Chandra Nair, ETC’s Senior Vice President, observed, “This was the first comprehensive ergonomics study of CAD users in which these two contrasting working styles were measured using ETC’s suite of physical and perceptual measurements. It demonstrates that the two-handed working style provides measurable benefits to CAD users, and should be reviewed by CAD managers and safety managers alike.”
The two-handed CAD working style enables the user to zoom, pan and rotate their model with a 3D motion controller, such as a SpaceBall or SpaceMouse, using slight, smooth continuous motions to quickly orient the model to the desired position. Meanwhile the mouse hand can rest and stay poised to perform the desired operation. In contrast, the one-handed style requires a combination of multiple mouse movements and keyboard modifiers to first position the model, and then additional mouse movements to perform the operation. This longer series of actions to first navigate, and then operate, explains why the one-handed approach requires nearly three times the amount of hand motions.
The complete ETC report can be found on ErgoWorld.
