Block 1: Orienting the scan using Grasshopper

The orientation of the STL scan in a 3D workspace dictates how it is translated into a 3D CAD model. The Grasshopper program requires the user to orient the model such that the surface that conforms to the user can be seen in the XY-plane and that the front of the seat cushion or the bottom of the back support runs parallel to the Y-axis, as shown in Fig. 4.

The correct orientation setting to begin the Grasshopper scan-to-CAD process. The Grasshopper program requires the user to orient the model such that the surface that conforms to the user can be seen in the XY-plane and that the front of the seat cushion or the bottom of the back support runs parallel to the Y-axis

Block 1 enables the user to orient the STL cushion scan in the Rhinoceros modelling space regardless of the scan’s original orientation, one of the three key actions listed in Fig. 1. The programming block enables the user to rotate the scan about the X-, Y-, and Z-axes separately in such a way that any rotation is accounted for the other axes without the user needing to take action to ensure this. Each axis of rotation is defined in Grasshopper as the unit vector of its axis. The input of each rotation is connected to the user interface with sliding bars, enabling full rotation about each axis by the end user.