exploring methods for putting holes in cylinders...
I was just experimenting with some things that tend to be difficult in modeling, one of which was putting holes in a cylinder, and I came up with the following.
There are often times when you would like to put holes into a cylindrical shape, for example a heat guard around a muffler or truck exhaust stacks or perhaps a kind of thingy you see on gun silencers and such.
One way of approaching the problem is to use boolean difference and a bunch of cylinders stuck into the main cylinder. This works but can be messy and time consuming to clean up, so I thought I would try a different method.
I laid everything out on a poly plane, then used a bend deformer to roll the plane into a cylinder, merged the verts at the top, and finally extruded a couple times for thickness and tight corners.
I came up with two geometric patterns.
Both start with just the top face of a 8-sided poly cylinder. I extrude in the hole. Then I created two different patterns with 8 unit holes (see the images below). Next I simply used the bend deformer to wrap them into a cylinder using a curvature value of 3.141592 (remember PI). Since the bend is from the center you are making a curvature of PI from both ends so the total curvature is 2PI which is the number of radians in a complete circle.
I came up with two patterns one uses fewer polygons but has a subtle wave pattern that I find makes a pleasing form.
The other makes a more uniforn cylindrical surface, but has a slightly denser mesh. To make this pattern, I just started with the octagonal pattern and replaced all the diagonal cuts with horizontal and vertical ones so the edges flow more uniformly along the height and span of the cylinder.
I can see applications where I will be using both styles.
This method has other applications as well. Applying a wrap deforming to a plane of any size you can form a mesh with holes in it around any surface such as a helmet or shoulder pads.
I hope that folks might find this idea useful in their own work.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675
Last edited by ctbram; 13-12-2009 at 01:13 PM.