For each polygon, I want to get the EdgeIndex of the longest edge (ultimately, I want to get the midpoint of the longest edge for each polygon).
It’s a relatively simple thing to do, but to get to edge midpoints, there’s a few context hoops to jump through:
I guess I could most of the context conflicts by putting the ICE tree on the mesh and storing the midpoints there.
Here’s a question from the Softimage mailing list, and what I would have answered (I didn’t answer, and I didn’t peek at the other answers either).
Given a 100×100 Grid point cloud, how would you do something to the following subsets of points?
[0,5,10, ... 595] and [1000,5,10, ... 1595]
For something like that, modulo is an obvious way to do it:
Contrast the above with this nicer tree
See also this for some compounds.
Given an array like
[0, 3, 7, 22, 6, 71, 1, 0, 9]
how do you sum up the first group of three elements (0+3+7), the second group of three elements (22+6+71), the third group (1+0+9), and so on and so on, without using a Repeat node?
Well, you could write your own custom ICE node. Or you could use Generate Sample Set like this:
Another Rotate Vector example. This time, I rotate the points of a mesh around the global X axis. In short, the point positions are treated as vectors, and then rotated about the specified axis. Of course, this requires some conversion between coord systems, which is always fun :)
The bottom part of the tree is just for visualization.
Here’s a couple of examples to illustrate how to use Sort Array with Key.
Note the use of Get Point ID, which works even if the points don’t have their ID attribute set.