Technical description

diddon · 25 Sept 2010, 13:18

Hi, I am hoping someone can help with a technical description I am having trouble putting into words. Basically I am looking for the correct terminology that describes any object that if you have two of said object one can be rotated 180 degrees and fit on to or in to its pair to form one perfectly symmetrical object.
An example sketch can be found here: http://www.jollyg.com/whatsthis.jpg
I was thinking along the lines of rotational symmetrical fitting but it doesn't sound quite right.
Any ideas?

Dave R · 25 Sept 2010, 13:37

Interesting question. How about 'identical mating parts'?

charly2008 · 25 Sept 2010, 14:10

Hi Dave,

I hope I have understood your question correctly. I would do it as follows:

Make one part and make it a group. Take copy and flip it along Component's Red and than flip it along Component's Blue. And then move the two parts together.

Charly

Untitled.skp

Dave R · 25 Sept 2010, 14:13

Hi Charly,

I think the other Dave was actually just asking what description you would use to describe the two parts which are identical but will mate with each other as you have shown in your illustration. I read his question as asking for the words instead of the pictures. Maybe I missed something, though.

mitcorb · 25 Sept 2010, 14:13

Opposing, interlocking? Interfacing, interlocking?

honoluludesktop · 25 Sept 2010, 14:26

Regular Division of the Plane with Asymmetric Congruent Polygons?-)

mitcorb · 25 Sept 2010, 14:45

Thesaurus suggested amphichiral, as in amphichiral knot having to do with mirror images. Amphi-, in Greek means "both".

diddon · 27 Sept 2010, 11:15

Thanks for the suggestions so far... I'm not sure it's quite there yet (although amphichiral is an impressive suggestion).... I found 'splice joint' which is common terminology in woodwork. Does any one know if this can then be used across all materials in product design?

mitcorb · 27 Sept 2010, 18:14

Well, no one said you could not spice up your commentary with metaphors (another word of Greek origin)

Jim · 27 Sept 2010, 19:19

lap joint (or is it a half-lap?)
pegged lap joint.
interlocking lap joint
pegged half-lap joint.
doweled half lap.
half-pegged half-lap.
half-lap joint with integrated pegs.

jeff hammond · 27 Sept 2010, 19:54

that joint in particular would be a splice joint of sorts.. lap joints tend to cross each other or form corners whereas a splice joint connects end-to-end.

still, i don't think diddon is looking for that type of answer..

if we were talking graphics, i'd say ambigram would be a good place to start (turn it upside down and it reads the same).. but i don't have a clue as to what the proper term for the reversible mating parts would be.. interlocking, universal, or something like that might be in the term though.

mitcorb · 27 Sept 2010, 21:48

From Wikipedia:
Reflection symmetry
Main article: reflection symmetry

Reflection symmetry, mirror symmetry, mirror-image symmetry, or bilateral symmetry is symmetry with respect to reflection.

More fuel for the fire.