Showing posts with label AutoCAD. Show all posts
Showing posts with label AutoCAD. Show all posts

Monday, January 15, 2007

Three intersecting cylinders

Just for fun, using "union" instead of "intersect" on three orthogonal cylinders, following shape was generated (3D wireframe):And the rendered image (material set as blue marble):

Sunday, January 14, 2007

Object of interest

Some time ago my friend asked me an interesting question: what body (possessing internal volume) has three orthogonal projections being circles (of the same radii), but isn't a sphere. I could imagine a stationary view of such object, but couldn't really rotate it in my head. I guess, my rendering software needs some practice ;-). Sasha Parfenov (my friend) actually made it out of paper. At first I thought about making it out of Styrofoam using a cookie-cutter technique, but instead I decided to read AutoCAD manual a bit more. After ~1 hour of reading and tweaking the object was drawn and rendered from different angles:Orthogonal projections:It would be really cool to machine this body on lathe (from brass). Maybe in a very distant future it will happen. But for now here is the next best thing:I couldn't find description of this body in any of my math books nor on the Internet. A hypothesis that it is a "cylindroid" wasn't correct. One definition of cylindroid is:
cyl·in·droid
n.
1. A cylindrical surface or solid all of whose sections perpendicular to the elements are elliptical.
2. A mucous thread with pointed or split ends, observed microscopically in the urine, and resembling a urinary cast.
adj.
Resembling a cylinder.
Cylindroid is also a different name for Plücker's conoid. It would be interesting to find out the actual name of this body.

P.S. The object's name is a tricylinder. The general name for a body formed by an intersection of cylinders is Steinmetz Solid. Looking through some of the 3D objects on WolframMathWorld, I finally found it after searching for "intersecting cylinders". The 3D applet they use is very cool and many shapes are pretty interesting