## 20110109

### Parametric Patterns VIII: Point Collections

##### Point Collections

“Organize collections of point-like objects to locate repeating elements.”

Revit and Vasari’s  handling of point collections is a little uneven.  For regular 2d collections (points arrayed along a plane or surface), the Divided Surface functionality makes collecting and organizing points almost trivial.  Non-regular distributions require a little more work, using Intersects.  1d collections (points arrayed along a line or curve) get a little hacky, the best way I have is to use the Divided Surface functionality on an extrusion made from a line.  3d collections (points arrayed in a volume) are pretty much the domain of API plugins or fairly manual processes.

Another note on Divided Surface, and one that is often confusing to folks: surfaces are only broken up into rectangular grids.  Now, this does not mean that you are only able to create rectangular distributions, there are pre-baked templates for triangles, octagons, arrows, etc.. The requirement is that the distribution of elements along the surface need some underlying rational that finds 4 sided cells at it’s base.  For example: a hexagon can be expressed from a collection of 6 rectangles, as with this pre-baked template

or 2, with this  math driven version

or even 1

All depending on your needs.  Heck, you can do a Celtic Knot or Gothic tracery with a rectangle (for all your Renaissance Fair clients and bad powerpoint templates)

But I digress.

Most of the examples shown by Woodbury are very achievable with basic divided surface functionality.  Volumes, as I mentioned, are difficult to achieve, and I won’t show any examples for these.  Volumes either need API or some cumbersome manual manipulation which make for dull videos.  Another difficult, but not impossible, affect to achieve through existing functionality is creating complex relationships between points such as identifying a set of points and connecting each one to another set of points.

#### Whorl

“Simulate a whorl of water or air.”

Point Whorl

#### Spiral

“Place a sequence of points along a spiral.”

This example builds on spiral formations covered in a couple other posts, primarily a tutorial on creating a spiral path, but information on Incrementing helps too.

Points on a spiral