dracae wrote:

kayybee wrote:

I'd love to switch to trig angles too, but if we do, then we break either all the projects that already use te old system, or all the projects that made the workaround for trig angles.

And if we leave those there, and use trig angles for new projects, tons of new scratchers or anyone who don't read the announcements will get confused, especially because old projects aren't consistent with the way they changed to.

Any other ideas then?

What are your thoughts on what I suggested?
Two options for angles, similar to the options for rotation.

That might be confusing as that panel is very hidden, but maybe it could be “point in {trig v} direction ___” so you can choose on the block.

kayybee wrote:

That might be confusing as that panel is very hidden, but maybe it could be “point in {trig v} direction ___” so you can choose on the block.

+1337

I think they should have it default to Scratch directions on the old projects so they aren't messed up.

Make the other options tucked away where you have to look to find them, an I guess you're okay. In my opinion, it's too confusing to have them right out there in the open, but that option might still work.

Here's what it'll be like:

The top is default, and the bottom displays the options.

(YOU BETTER APPRECIATE IT! I SPENT SO MUCH TIME! APPRECIATE, OR ELSE!)

dracae wrote:

Here's what it'll be like:

The top is default, and the bottom displays the options.

(YOU BETTER APPRECIATE IT! I SPENT SO MUCH TIME! APPRECIATE, OR ELSE!)

+9001

I think rotation and direction should be the same, so just “set direction system” or “set rotation system”.

dracae wrote:

Here's what it'll be like:

The top is default, and the bottom displays the options.

(YOU BETTER APPRECIATE IT! I SPENT SO MUCH TIME! APPRECIATE, OR ELSE!)

That's a great idea! And with the

kayybee wrote:

I think rotation and direction should be the same, so just “set direction system” or “set rotation system”.

even better!

MalinC wrote:

dracae wrote:

Here's what it'll be like:

The top is default, and the bottom displays the options.

(YOU BETTER APPRECIATE IT! I SPENT SO MUCH TIME! APPRECIATE, OR ELSE!)

That's a great idea! And with the

kayybee wrote:

I think rotation and direction should be the same, so just “set direction system” or “set rotation system”.

even better!

It's so beautiful…

*poignant tear rolls down cheek*

i think the rotation style would be the way to go. if we just changed the system it would destroy existing projects with trig. i agree it is very confusing though, so it should be changed and perhaps the correct system should be put as default.

I have to admit that I'm a bit bemused by how much of an issue this appears to be…

I don't recall ever learning at school that angles had to be measured from the x axis going anti-clockwise, nor learning equations involving trig that were specific to that orientation - IIRC, it seemed to be much more generic. The only specific case I can think of was learning about complex numbers on the complex plane (you know the ones - involving square-root of -1…), which is basically just to do with co-ords of a circle, when it comes to it. (Also, certain functions like atan2 have to be defined a specific way around for computer use - but that's not school level…)

I wonder if it could possibly highlight a bit of a deficiency these days in the way such things are taught? Do you guys at school just learn various equations and how to use them for specific tasks, and not really the ‘why’ of the equations? -i.e. not so much why they take such a form, where they come from, how they get to be the way they are…?

OTOH, perhaps I'm just too old and have forgotten it all by now in those terms.
(They do say once you start A-levels, and even more so into Uni, that you end up having to relearn everything. So maybe……)
(And maybe that's why the Scratch Team haven't considered it to be particularly problematic? -a bit of a disconnect between older understanding of things vs the way they are now taught at school?)

Anyway, just me being curious -so, can someone (who is rather younger than me! or maybe a teacher?) comment on what's difficult, or confusing, about taking an angle clockwise from ‘vertical’ (rather than anti-clockwise from x-axis). In particular, relating that to other things you might do with it in scratch (trig, and x & y co-ordinates of stuff, perhaps?)

Thanks!

I made an interactive Scratch explanation.

DadOfMrLog wrote:

…
I wonder if it could possibly highlight a bit of a deficiency these days in the way such things are taught? Do you guys at school just learn various equations and how to use them for specific tasks, and not really the ‘why’ of the equations? -i.e. not so much why they take such a form, where they come from, how they get to be the way they are…?
…
Anyway, just me being curious -so, can someone (who is rather younger than me! or maybe a teacher?) comment on what's difficult, or confusing, about taking an angle clockwise from ‘vertical’ (rather than anti-clockwise from x-axis). In particular, relating that to other things you might do with it in scratch (trig, and x & y co-ordinates of stuff, perhaps?)

Now that I remember, on a pre-calculus exam, I was asked to convert the cartesian equation of a circle to polar. In general, it should have been x = r*cosΦ; y = r*sinΦ, but having Scratch fresh in the mind caused me to switch the trig functions. So yeah, the way the angles are can really interfere on math tests…

From what I'm taught, sine is the y, cosine is the x, and tangent is y/x. Scratch is the total opposite.

@MalinC: Nice project!

Doesn't really explain why angles should be measured anti-clockwise from x-axis, though - just suggests, perhaps a little oddly, that's what the ‘MathAngle’ is (not really sure what that means - and I'm a mathematician!) That may be the convention in particular applications (e.g. applying angles with trig to the simplest 2D circle-centered on origin co-ordinates, 2D polar co-ords {basically same as circles}, or complex numbers {pretty much same again}), but I'm a bit surprised that such specific applications have come to be kind of the way angles in general appear to get ‘defined’…

I'm curious: when faced with a right-angle triangle drawn at some random orientation in some maths test, with the requirement to find some side length via trig using a known angle (or vice versa), do you have to spin the paper (mentally, or maybe even physically!) to make the adjacent and opposite sides of the triangle line up with the x and y axes?

@ProdigyZeta: “From what I'm taught, sine is the y, cosine is the x, and tangent is y/x.” Wooow… Curious! Again, that's certainly the convention in specific applications of trig (as mentioned above), but to make it more general seems somewhat … I dunno… maybe even ‘dangerous’ for future progress. I only recall first learning sine/cosine in the context of ye olde SOHCAHTOA (where triangle orientation, and angle direction, is irrelevant), and then a bit later seeing how it can be extended to apply to circle/polar co-ords as a specific case.

Oh dear, am I being a bit of a rebel and ruining what your teachers are trying to teach you…

dracae wrote:

Here's what it'll be like:

The top is default, and the bottom displays the options.

The current direction system (analog clock) would be the default, to be clear, with 0 degrees on the top.
The trig version would be going counter-clockwise, with 0 degrees/radians on the right.

(EDIT: Oh shoot, i did direction system and rotation system!?!?!? No wonder why some people are confused! D: )

DadOfMrLog wrote:

That may be the convention in particular applications (e.g. applying angles with trig to the simplest 2D circle-centered on origin co-ordinates, 2D polar co-ords {basically same as circles}, or complex numbers {pretty much same again}),

Exactly!

dracae wrote:

What system is Scratch's direction based on anyways!?

I think it's compass bearings, where 0 is north and it goes clockwise. But I don't know why it goes from -180 to 180 instead of 0 to 360.

joefarebrother wrote:

dracae wrote:

What system is Scratch's direction based on anyways!?

I think it's compass bearings, where 0 is north and it goes clockwise. But I don't know why it goes from -180 to 180 instead of 0 to 360.

because kids equate -90 and 90 as “opposite”, which is true as left is opposite right. its less obvious to view 90 and 270 as opposite.

I fixed it:

(EDIT: Top is default.)

MalinC wrote:

DadOfMrLog wrote:

That may be the convention in particular applications (e.g. applying angles with trig to the simplest 2D circle-centered on origin co-ordinates, 2D polar co-ords {basically same as circles}, or complex numbers {pretty much same again}),

Exactly!

The key words there are “particular applications”. There's no reason these should define what ‘angle’ actually means. Each is just use of angles in a specific situation, and are made to correspond for convenience.
Indeed, there are *many* cases in mathematical/physical situations where the angle is traditionally measured from the vertical. Take spherical harmonics, for example (which I guess is due to the use of spherical co-ordinates). Or transverse anisotropy (the angle is the tilt measured from vertical). As you look at both of these from a typical viewpoint, the ‘tilt’ angle would appear to follow just the same the way scratch defines it…

From the way I think of it myself, I'd say an angle is simply something that's measured between any two lines (with any orientation). And you can measure it any direction from any of the lines to the other - you'd probably choose one that makes the maths work out most conveniently for your specific case. I suspect it becomes even more important to be able to think in such terms once you enter the 3D world, where trying to work with angles that are at different orientations in different planes makes it clear you need to think rather differently about it (and things start to get quite messy with angles - if you think trig in 2D is bad, look up “spherical trig” on wikipedia!)

I suspect it'd prove to be a really useful ability to get used to using angles in lots of different ways/settings - seeing how the more general ideas translate into the specific cases. In that sense, while there's clearly something of an uphill struggle to begin with (which may be due to some possible issues in the way it's taught?), it may even prove to be a worthwhile endeavour to get to grips with how it works in Scratch, and be able to relate the various cases through the more general concepts.

Anyway, I'm causing too much trouble, so I'd better shut up now

Wes64 wrote:

joefarebrother wrote:

dracae wrote:

What system is Scratch's direction based on anyways!?

I think it's compass bearings, where 0 is north and it goes clockwise. But I don't know why it goes from -180 to 180 instead of 0 to 360.

because kids equate -90 and 90 as “opposite”, which is true as left is opposite right. its less obvious to view 90 and 270 as opposite.

-180 and 180 are opposite numbers, but are the same angle, so…

(Also, -90 exists on any angle system as it is coterminal to 270, so the same thing applies for 270)