Stretchy minute hand

I am working on a watch face with a tourbillon hour hand and a large retrograde minute hand. I am using the expression (490 + (#DWFMS#/ 360 * 260)) and it works fine for 0 - 30 minutes, but then goes wrong.



How can I make the minute hand shrink after 30 minutes?

3 Likes

You can do it with two hands hiding the one that has gone off track . You can use a non liner formula involving sin and rad or you can look at a +/- formula and use abs in it . I will have a look after Dinner . That particular hand is not best for stretching as it will change shape.
.
This is a very crude solution following on from your Liner Concept . I found the scale you have a bit misleading . Going from 0 to 55 . Well if you wanted to run it in 5 minute steps that would be fine .

I will have a look at a non liner but someone might get there before me .
BTW I used the Minute hand for this test .

Hand Length

(500+(130-(((abs((#DWFMS#)-180))/180)*130)))

hand rotation

(218-(((#DWFMS#)/(360/76))))

3 Likes

The curve looks elliptic, so using the the formula for an elliptical path, the formula for the height would be (used seconds for easy simulation, you can change to minutes):

(468/(sqrt(1-0.36*sin(rad(#DWFSS#/2)))))

I am assuming 220 degrees path as opposed to @russellcresser - makes it a little easier with the formulas.

So the rotation is:
(220-(((#DWFSS#)/(360/80))))

The Hand details (using the standard one in your diagram):
X: 160
Y: 17
Width: (146/(sqrt(1-0.36*sin(rad(#DWFSS#/2)))))

This width makes the hand look proportionate all the time, although it only varies between 146 and 182.

4 Likes

Looking forward to checking that out Tom . When I am simulating angles I use #DWFHS# . Then I can use the time machine slider . I some times use it for positions stuff as well and Write the numbers down for later .

3 Likes

Fantastic work TOM . Great education this Community is . Thank you very much .
.
.
TOMSTRETCHHAND-ezgif.com-video-to-gif-converter

2 Likes

To me the minute scale looks asymmetric. It has 6 steps on left and just 5 on right side. Btw. what is the hand supposed to do between 55 an 00?

3 Likes