Making circles on the surface of a mesh

Taking a cluster of points and moving them on to a circle turned it to be easier than I thought… At first it seemed more complicated to get at the points, because sometimes the Show Values on the output of a Filter node is, let’s face it, misleading. Based on what a certain Show Values showed me, I started off using arrays instead of Filters, and that made the graph a little messier.

First, I calculate the point I want to use as the center of the circle. That gives me the first vector I need.

Subtracting the CC (circle center) vector from the PP (Point Position) vectors gives me a set of vectors that take me from the circle center to the points.

I just resize the PP-CC vectors to get point positions that fit on a circle:

Using vector subtraction to move a point onto a circle

Circles, spheres, and radii…

For a couple of reasons, I was playing around a bit with spherifying/circulizing this weekend:

Based on this basic idea: “every point on a sphere/circle is the same distance from the center”, I was able to rough-out a couple of ICE trees:

Creating a circle on the surface of a mesh required just a little bit of 3d vector math. Here’s a little video that goes over using vector subtraction to move a point onto a circle. I spent more time setting up the “Show Values” in my demo then I did recording the thing.

Scene walkthrough – Polygons following particles

In this video, I do a walk through of a scene posted by Guillaume Laforge on the XSI mailing list. In the scene, Guillaume uses a point cloud to drive the polygons of a mesh, so that the polygons follow that transformations (pos and ori) of the particles. ICE modeling is used to “break up” the mesh into polygons. Includes a description of how vector subtraction is used to locate points relative to a polygon center.