Oolite Bulletins

DaddyHoggy wrote:

My understanding of axes of symmetry must be odd compared to everybody else's. Can somebody explain why the Liberator is symmetrical in three axes? I can see if you split it length ways, nose to tail it would be symmetrical side to side, but not top to bottom...

Kids today, DH. They don't know what symmetry means. The Liberator is an example of what I was saying, it is, of course, bilaterally symmetrical when viewed from front or back, but not from any other direction. It has one axis of symmetry only.

Wildeblood wrote:

DaddyHoggy wrote:

My understanding of axes of symmetry must be odd compared to everybody else's. Can somebody explain why the Liberator is symmetrical in three axes? I can see if you split it length ways, nose to tail it would be symmetrical side to side, but not top to bottom...

Kids today, DH. They don't know what symmetry means. The Liberator is an example of what I was saying, it is, of course, bilaterally symmetrical when viewed from front or back, but not from any other direction. It has one axis of symmetry only.

I think that is wrong actually.

This would be three axis of symmetry.

Gimi wrote:

Wildeblood wrote:

DaddyHoggy wrote:

My understanding of axes of symmetry must be odd compared to everybody else's. Can somebody explain why the Liberator is symmetrical in three axes? I can see if you split it length ways, nose to tail it would be symmetrical side to side, but not top to bottom...

Kids today, DH. They don't know what symmetry means. The Liberator is an example of what I was saying, it is, of course, bilaterally symmetrical when viewed from front or back, but not from any other direction. It has one axis of symmetry only.

I think that is wrong actually.

This would be three axis of symmetry.

That can't be what 3-axis symmetry means can it? If I built a ship that was perfectly circular in any one plane, that would have infinite axes of symmetry...

Axes of symmetry are surely - left-to-right, top-to-bottom, front-to-back?

DaddyHoggy wrote:

My understanding of axes of symmetry must be odd compared to everybody else's. Can somebody explain why the Liberator is symmetrical in three axes? I can see if you split it length ways, nose to tail it would be symmetrical side to side, but not top to bottom...

It's got a threefold rotational symmetry, and three planes of symmetry along its length. I think. Doesn't it?

Edit: which, of course, is one axis of symmetry.

OK. Right. The TARDIS, I'm reliably informed, has 317 axes of symmetry, on a good day.

I was under the impression that axes have to be at right angles to each other.

Thus the Liberator has only one axis of symmetry, yet you can draw three lines of symmetry with no difficulty.

In fact, being particularly picky, given the orientation of the engine housing (or whatever the glowing green thing hanging out the back is) there is only one possible line of symmetry.

Cheers,

Drew.

This depends on what type of symmetry we are talking about. When discussing a 3D model of Oolite, I assume it is Reflection Symmetry.

There is no rule that says that lines of symmetry have to be at right angles to each other, and yes a Circle has infinite axis of symmetry.

Reflection Symmetry

Drew wrote:

In fact, being particularly picky, given the orientation of the engine housing (or whatever the glowing green thing hanging out the back is) there is only one possible line of symmetry.

Drew has a point here though.

drew wrote:

I was under the impression that axes have to be at right angles to each other.

No. To the best of my knowledge, that isn’t true for any meaning of “axis”. But to clear up some confusion:

•  In two dimensions, an “axis of symmetry” divides a shape into mirror-image parts. The 3D equivalent is a plane of symmetry.
• In three dimensions, an “axis of symmetry” is a centre of rotational symmetry. The 2D equivalent is a point of rotational symmetry.

Ignoring the details of the back, the Liberator has three planes of mirror symmetry and one axis of threefold rotational symmetry.

All this because I said Cmdr Wyvern's model would look better with only two nacelles, not four, to give it a definite up-down direction. Dear me. No one mentioned symmetry, you just imagined it, move along.

I'm assuming from this conversation that no one remembers the whole point OF this topic.....

Should I repost my model?

Dragonfire wrote:

I'm assuming from this conversation that no one remembers the whole point OF this topic.....

Should I repost my model?

There was a model...?

Dragonfire wrote:

Should I repost my model?

Dunno. Is it symmetrical?

Okay, you nutcases. Here is the post again.

[quote=Dragonfire]This is my first model, so my apologizes about it being a smidge rough. As of yet, it is unskinned.




If anyone has any ideas on how to improve it, they are more than welcome to take the .obj file and tweak the model to their heart's content. They can then submit it as their own design.
http://dancingword.net/oolite/wyverndf.obj[/quote]

It needs not to have such a neat edge - it reminds me of a really cool "boomerang" I once had - a few protrusions on the edge itself, a few bulges top and bottom, just to take the plainness away..

Well, I can definately put a few cones in along the edge as spikes. I meant to put the horns in, too...

Removing my model from the compo. Sorry.