Full Version: Angle Numerical Entries Problem

I was just experimenting with creating a sketch similar to the one in the link below using polyline.

https://image.slidesharecdn.com/20-days-of-2d-cad-exercises-part-i-211217171509/75/20-days-of-2d-cad-exercises-part-i-4-2048.jpg

However, I ran into some difficulty at the non-perpendicular angles (0,90,180,270). When I enter the angle in the angle tab at the lower-left (next to the distance), the angle is always measured from the positive X-axis as the starting point. I think it would be really helpful if there was an option to have the angle we input be based on the last line of the polyline as the starting point instead.

Is this something that could be added in a future update? (Consider this a feature request). Thanks a lot!

---

Turtle graphics has Turn() and SetHeading() commands.
Some angle translation would be needed.
Turning 180, then turning stated angle, uses some existing angles...

-Brian

I vaguely recall a turtle script in MoI, unless mistaken.
MoI Search of "Turtle" yields script.

---

Hi bemfarmer,
I found this one: https://moi3d.com/forum/index.php?webtag=MOI&msg=7515.1

Will try it for certain. Thank you for pointing this out!

---

Hi Elang, do you have any ideas on how the option could work?

I was thinking maybe if you prefixed your number in the angle field with "r" (for relative) that could do it, like type in r99.

- Michael

---

Hi Elang, one way you can do it currently aside from rotating or setting the construction plane is to use an angular dimension as a drawing aid.

So if you've got an initial line like this:



You can put in an angular dimension and enter in the angle for it:



Then you'll have a snap point on the dimension:



- Michael

Image Attachments:
angle_dim_snap1.png  angle_dim_snap2.png  angle_dim_snap3.png 

---

Hi, Michael... pardon for late reply.

I think something like r99 (turn right 99 degree) or l99 (turn right 99 degree) should be convenient and easy to understand.
That is of course only work with polylines (which record the last point of the line so Moi knows the starting point for left or right)

Also, Michael... IMHO, most of Moi users will expect that the '<' input tab should consider the starting point of line creation rather than 0 is the +X axis (?). The '<' tab almost never used for rotation purpose, isn't it? Or maybe it is just me... ^^

Thank you very much for your attention.

---

That's surely works, Michael!

Only thing is it takes 3 steps for expectedly simple creation.
Moi3D is loved for its intuitive UI, so I believe it's better to keep it that way. ;)

Sincerely.

---

Hi Elang,

re:
> Also, Michael... IMHO, most of Moi users will expect that the '<' input tab should> consider the starting point of line creation rather than 0 is the +X axis (?).
> The '>' tab almost never used for rotation purpose, isn't it? Or maybe it is just me... ^^

The current behavior to use 0 being the x axis is modeled after polar coordinate entry in AutoCAD.

> I think something like r99 (turn right 99 degree) or l99 (turn right 99 degree) should
> be convenient and easy to understand.

That seems good, then it could also work to give a distance value like 5r99 = distance of 5 from the previous point and angle of 99 degrees from the previous line.

- Michael

---

Hi, Michael

>then it could also work to give a distance value like 5r99 = distance of 5 from the previous point and angle of 99 degrees from the previous line.
That's even better !.. Yes, please! ^_^

Sincerely

---

Hi Elang, I took a look at this a bit more today and there's kind of a complication.

If it's set up as "angle turning to the left or right", that would mean a turn of 0 would just keep going in the same direction as the previous line, right?

But your figure you posted above is not measured using that, it uses the opposite direction.

For example your figure measures 67 degrees like this:



As the angle decreases, point C comes closer to point A with segment BC. With an angle of 0 you'd have line BC going in the opposite direction from AB, right?

But specifying the amount of turn to the left or right would be like this instead, wouldn't it? :



- Michael

Image Attachments:
TurnToRight1.png  TurnToRight2.png 

---

Hi, Michael... yes indeed!

Actually what I did was put 270+67 in the '<' tab to achieve the exercise. First, I checked if I put the end-point 'right below' then what is the '<' stated. Turns out that it was (and always) 270, so I add it with 67 to achieve the same result. However, 'the snap' would also includes snap to X Axis.

Maybe, to achieve the same result we can put like "65r_67" ? ( @_@; )
The '_' goes for 180-x degrees... so '_67' = '180-67' ?

I don't know which way is better, to be honest....

---

Would adding 4 snap lines resolve the ambiguity of r67? Say the black line is the prior segment and magenta is the snaps:



- Peer

Image Attachments:
relative angle.png 

---

Hi
Maybe it makes more sense to use "clockwise" and "counterclockwise" definitions instead of left or right.

E.G. c99 or cc99

c0, cc0, c360 and cc360 will be on the last polyline segment, And c180 or cc180 will be along the last polyline segment.

---

Hi Peer,

re:
> Would adding 4 snap lines resolve the ambiguity of r67?

It could for picking with the mouse but not for controlling it by text input alone.

- Michael

---

@MO,

re:
> Maybe it makes more sense to use "clockwise" and "counterclockwise" definitions instead of left or right.

Maybe it's not so bad for left and right to mean make the point on the left or right hand side but it doesn't necessarily also have to be a "directional turn angle".

- Michael

---