In structural mechanics simulations, a common output variable is a set of vectors representing the movement or displacement of geometry. Each displacement vector specifies a translation of a node from its original position (an offset). EnSight can display and animate these displacements to help visualize the relative motion of geometry.
In many cases, the magnitude of the actual displacements is extremely small relative to the size of the model. EnSight provides a displacement factor to scale the vectors and exaggerate the displacement.
For Model Parts
Displacements can be applied deeply on the server (in which the displacement vector is actually added to the coordinates) or on the client (in which the graphical entities on the client are displaced visually only using the graphics card). Server-side applied displacements (Displace computationally toggle ON, default) will apply the displacement on the server coordinate prior to a calculation or operation. Client-side (Displace computationally toggle OFF) displacement occurs after calculations and operations. Thus, for example, toggle on the Displace computationally toggle to see the calculated volume change, and toggle this off to see the volume remain unchanged. And, for example, if you wish to make a cutaway down the centerline of your model then show the cutaway displaced, turn off Displace Computationally, make your cut, and then pick your variable to use in displacement, so that your cut occurs before the displacement.
For Created Parts
Created parts can only be visually displaced
A part created using a parent model part that has been computationally displaced on the server will apply the displaced coordinates to the parent then create the part. This created part will show up with part displacements turned off, yet will be displaced because it used the changed coordinates of the parent when it was created. Warning: if you then turn on visual displacements on this newly created part, then it becomes twice displaced: once from the changed model part coordinates, and once from visual displacement on the client.
And a part created using a parent model part that has been visually displaced will use the original, undisplaced coordinates to create the part. This created part will also show up with part displacements turned of and will not be displaced because it used the original, undisplaced coordinates of the parent when it was created. If you then turn on visual displacements on this newly created part, then it becomes once displaced: once from visual displacement on the client.
A simple summary of cutting a model part is as follows. Cutting a visually displaced part does a cut then move. Cutting a computationally displaced model part does a move then a cut.
So if you create a plane cutaway on a model part that is computationally displaced, the cutaway will appear to grow through the fixed plane as more of it displaces through the plane because it is using the displaced coordinates prior to making the cutaway. If you create a plane cutaway on a model part that is only visually displaced, the displaced cutaway part will remain of fixed size and not move. If you turn on visual displacements, the cutaway will remain the same size and then start to move because the cutaway occurs on the undisplaced part and then that cutaway moves visually.
Note: If you select parts that are heterogeneous (some model parts, some created parts), the dialog will always show the computational displacements unchecked and greyed out (unchangeable) so that the displacement is visual only. This is because created parts can only be visually displaced, and model parts can be either computationally or visually displaced so the dialog chooses the only possible displacement common to both: visual.
Important: A common mistake is to make cutaway part using undisplaced model parts and then to select all and turn on displacements. This will turn on visual displacements only.