Calculating Angles (math problem I suspect)

[cgmonkey]

First off all, Hello everyone!

I'm using MMF2Dev Demo and I'm trying to calculate the angle of a specific object (Point1) relative to an anchor object (Anchor) using trigonometry.

You should get the angle from this calculation: TAN(x) = Point1X - AnchorX / Point1Y - AnchorY

Or my expression: Tan((X( "Point1" )-X( "Anchor" ))/(Y( "Anchor" )-Y( "Point1" )))

I can't get the right angle out of this, do you spot any immediate errors?

Thanks for your time
~B

Here's my file: http://www.gigasize.com/get.php?d=jwxl0ck108d

[uprize]

Can you use Advanced Direction Calculator extension? That has functions to calculate angle and distance between 2 points.

[MechatheSlag]

yeah the advanced direction calculator has this feature by default - and much more! Make sure to check it out

[Ryan]

For future reference,
To get the angle by itself you need to move Tan to the other side of the equation. It's Tan to the power of negative 1, or 1/tan.

Tan (angle) = opp / adj

angle = 1/Tan(Xa - Xb / Ya - Yb)

[cgmonkey]

Nice guys, really appriciate this!

Thanks for the correction, Ryan Basic 8th grade maths and I can't manage my head around it... PFF!

[Dynasoft]

Wrong again.

You want atan. Tan^-1() is different to Tan()^-1.

IIRC newer builds of MMF have atan2, which takes seperate x and y instead of x/y as the parameter(s), and so gives the correct result for x=0 or y=0.

[Ryan]

Yeah, Dynasoft is completely right.

I realised a couple of hours after posting that my logic in 1/tan was wrong. I was trying to remember the name for atan, but assumed 1/tan would have the same effect.