In a spin

rotateI’m no good at maths – never have been, no matter how hard I try. In desperation, trying to get me through my school exams, my parents even resorted to arranging additional tutoring – I passed, but only barely. It’s about the only subject I ever struggled with or found in any way challenging. Even today, ask me what 8 times 7 is and I’ll get the answer wrong at least half the time! Where I really struggled however were the the more arcane areas of mathematics – trigonometry made little sense to me, and as for algebra, forget it!

Over the ensuing years, necessity has driven me towards acquiring a modicum of mathematical skills that, had you asked me as a youngster, I would have never have held out any hopes of mastering. Even the dreaded trigonometry monster is now less of a demon, although it still befuddles me, but it’s a case of ‘needs must’, and consequently I’ve forced myself to grasp at least some of the knowledge that, in the past, was beyond my powers of reasoning. Not that I use an awful lot of trigonometry in my everyday life, however when it comes to SL, there are occasions when I have to thrust myself headlong into calculating angles, spatial relationships, and grappling with the mysteries of Pi.

I still don’t enjoy it, but some things just have to be done, like it or not.

Building anything more complex than simple plywood boxes is, at some point, going to require you to consider angles, degrees and and strong liquor – mostly in equal measures. Everything from joining prims to precisely fitting textures to faces is going to demand a basic knowledge of how things are supposed to fit together, unless – like so many – you are a graduate of the school of ‘moving stuff around until it looks like it’s right’, which is just fine, right up until you come to the end of six weeks of intensive building only to find that there’s just no way that the final piece is ever going to fit into its allotted place within the structure you have so lovingly bodged together. This type of construction follows a very simple rule: ‘The finishing touches to any build will take at least three times longer than all the work that has gone before, by virtue of having to completely reconstruct the whole thing many times over to correct your earlier mistakes’.

You eventually learn that it’s quicker, easier, and more satisfying to do it properly from the start.

It doesn’t help that SL is 3-dimensional: Whilst we’re pretty good at dealing with X, Y and Z axes in our everyday lives, that’s mainly as a result of not having to consider them too deeply. When it comes to constructing something inworld in three dimensions, with measurements, angles and spatial relationships to take into consideration, it all becomes suddenly a very different proposition.

As if building in three dimensions isn’t bad enough, things take on a whole new dimension when it comes to scripting, especially when considering rotation. Let us, for example, take Linden Lab’s definition of rotation as a starting point: ‘rotation can be viewed as a discrete twist in three dimensional space, and the orientation of an object is how much it has been twisted around from whichever axes we are using – normally the region’s axes’ – simple. Actually, the more you read it, the more more sense it makes! Then it all gets a little bit more mathematical and involved, with talk of quaternions, vectors, and converting degrees to radians, and thereafter, to said vectors. Complicated stuff, huh?

I wish it wasn’t so complicated, because mathematical geniuses like me </irony> invariably want to build things with wheels and spinning, rotating thingamajigs, and we plunge into the fray thinking it’s a fairly simple matter. Indeed, if you do a bit of research first, everyone in the know seems to be saying that rotations are straightforward and simple to understand really, once you get the hang of them, (and have imbibed sufficient ethanol) – however, these people have been paid by the Lab to lie – something that your few remaining cogent braincells will eventually grasp, shortly before turning to mush and running out of your ears.

verticalI should know better, I’ve struggled with rotating prims before, but on this particular occasion I had a very specific objective; one that I thought would be simple to achieve. I wanted to rotate a cubic prim around its X-axis, but with face 4 (the normal bottom -z face) orientated along that axis. Essentially, I wanted a rotating projector that would produce a vertical image on a screen.

After much trial and error – ok, mainly error – I’ve come to the conclusion that it cannot be done, unless you tilt the SL Grid on its side, which is probably also not viable. And now, I have given up.

But at least I now know what gimbal lock is!

s. x

And this just feels like spinning plates
I’m living in cloud cuckoo land
And this just feels like spinning plates
Radiohead – Like Spinning Plates

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