Apparent Layer Operations for the Manipulation of Deformable Objects

Figure 1: Apparent layer operations. Left: Layer swap allows the user to swap local layers under the clicked point. Right: Layer-aware dragging allows the user to drag over (shift-up) or under (shift-down) a colliding object in the screen space. We introduce layer operations for single-view 3D deformable object manipulation, in which the user can control the depth order of layered 3D objects resting on a flat ground with simple clicks and drags, as in 2D drawing systems. We present two interaction techniques based on this idea and describe their implementation. The first technique is explicit layer swap. The user clicks the target layer, and the system swaps the layer with the one directly underneath it. The second technique is layer-aware dragging. As the user drags the object, the system adjusts its depth automatically to pass over or under a colliding object in the screen space, according to user control. Although the user interface is 2.5D, all scene representations are true 3D, and thus the system naturally supports local layering, self-occlusions, and folds. Internally, the system dynamically computes the apparent layer structure in the current configuration and makes appropriate depth adjustments to obtain the desired results. We demonstrate the effectiveness of this approach in cloth and rope manipulation systems