 ## General

#### How does the setting “Invariant in X” etc. work for the Design Tool vertex motion defined in Region Conditions?

• FAQ
Participant

There is one section for each motion direction, i.e. “X Motion”, “Y Motion” and “Z Motion”. For each direction the motion can be enabled (Default), disabled or constrained by the “Invariant in X/Y/Z” flag. Some examples:
1) The default is to have “Motion Enabled” for all directions and no invariance constraint. So all nodes can move in all directions, based on the optimal displacement computed by the Design Tool.
2) Disabling the flag for “Motion Enabled” results in the node not being moved in the disabled direction.
2a) So if “Motion Enabled” is diabled for the “Y Motion”, then the y-coordinates of all nodes in the region will remain unchanged (fixed). In this example the nodes can only move in x- and z-direction.
2b) If “Motion Enabled” is diabled for the “X Motion” and “Y Motion”, then the nodes can only move in the z-direction. x- and y-coordinates are fixed.
3) The “Invariant in X/Y/Z” flag indicates that all nodes on the same X/Y/Z-location are moved by the same value in the related “X/Y/Z Motion” direction.
3a) If “Invariant in Z” is set for the “X Motion”, then the x deformation (the x component of the displacement) will be invariant in Z coordinate, which means x deformation is constant over different Z coordinates and it can vary over X and Y coordinates. So for example, all nodes on z=0 have the same x-deformation Delta x1 and all nodes on z=1 also have the same x-deformation, but with a different value Delta x2.
3b) When a constant X Motion for all nodes should be obtained, then all 3 flags “Invariant in X/Y/Z” for the X Motion have to be selected.
3c) To move all nodes of the region with the same deformation, i.e. like a rigid body, all 9 “Invariant in X/Y/Z” flags must be selected. 