A common display requirement for Vector Arrow displays is to make them uniformly spaced. Relying on the underlying grid resolution for the placement of the vector arrows can either obscure regions of interest, make it difficult to not overlay vectors on top of each other, or bias the viewer's interpretation of the results to certain areas of the plot. Therefore, having a uniformly-spaced vector arrow display is used quite often.
EnSight places Vector Arrows according to the node locations of the underlying part on which the Vector was created (in this case typically a clip plane). So, in order to create uniformly spaced vectors, the part on which it is created must contain uniformly spaced grid. The use of "Grid" based clip PLUS "Plane tool clip" are required to achieve uniform grid clip.
The following serves as a rough outline to the process and improvement of the vector arrow display creation.
1. Non-Uniform "mesh" style clip with vectors:
Image 2: The non-uniform location of the vectors is a result of the non-uniform "mesh" style of clip:
To achieve uniform "grid" style of clip, you must use the Plane Tool to create the clip. Place the plane tool to the desired location for the clip (see Help on Plane Tool for its placement/control). Ensure that the Plane Tool encompasses the region to be clipped, as the "grid" style of clip will be a "finite" clip of the plane tool:
With the plane tool placed, Create a "Plane Tool" based Clip, using the "Grid" option for the Clip. Adjust the "X" and "Y" to control the number of grid points in the X and Y directions of the plane tool:
The resulting Clip (with the grid display on) should now be a uniform underlying grid:
Now, you can use this "Grid Clip" as the Parent for creating the Vector arrows as normally done. The "uniformity" of the Vector Arrow Placement is a result of its underlying parent being "uniform", rather than an attribute of the vector part itself: