A three-dimensional (3D) computer aided design (CAD) user interface (UI) is describing using both two-handed and one-handed free hand gestures and poses to map to actions in the 3D CAD UI environment. Free hands may be used to directly both constrain and organically modify an object. Intuitive analogs to physical tools are used, with gradual changes to visibility. Parts are automatically modified to meet object-specific and rule-based constraints. Multiple copies of a physical analog element, with known dimensions, may be continually created by a free hand and automatically assembled into an appropriate, organized and contiguous structure containing integral visible fiducials based on the dimensions of the element. Temporary layers of an object are used to permit organic modifications of portions of an object. Use of a fastener creates and then fastens to a mating part. Visible physical analogs provide perspective. Non-linear magnification permits rapid, wide dynamic range object modification.
