partial torus prims

[Rene Rechthaler]

Hello, as stated here:
t04i8000-075.dat
we may need an addon for new torus prim variants...
as of now, there are only full or quarter (inside/outside) torus prims.
But sometimes we may need cut tori.
https://en.wikipedia.org/wiki/Toroidal_a...oordinates
toroidal is bigringwise (the rotation path), poloidal is smallringwise (the rotated profile)

my suggestion would be a suffix (like the -075)
and the number is the percentage of the full quarter inside/outside torus and the + or - is the direction
(from the inner/outer border or from the center line)

but you are free to discuss
(do we even need this? which way should it be done? 075 or 750? where does +/- start? and more...)

René

[Willy Tschager]

Hello, as stated here:
t04i8000-075.dat
we may need an addon for new torus prim variants...
as of now, there are only full or quarter (inside/outside) torus prims.
But sometimes we may need cut tori.
https://en.wikipedia.org/wiki/Toroidal_a...oordinates
toroidal is bigringwise (the rotation path), poloidal is smallringwise (the rotated profile)

my suggestion would be a suffix (like the -075)
and the number is the percentage of the full quarter inside/outside torus and the + or - is the direction
(from the inner/outer border or from the center line)

but you are free to discuss
(do we even need this? which way should it be done? 075 or 750? where does +/- start? and more...)

René

I'm not against it. We have tndis so why not this. Could you please make some renders as it has been done for:

https://forums.ldraw.org/thread-24731-po...l#pid41927

to get people a clear idea what we are talking about?

w.

[Rene Rechthaler]

   
something like this? (screenshot from LDPE edited with paint)

the addition itself:
t08o800 like the existing syntax
the +/- indicates from where to start
the number states how far to go (+100 would be the same as a -100, a full quarter, no suffix needed then)

usage:
could be useful for chamfers or partially prints
if a torus gets cut somewhere
-> could still apply to prim subst

[Travis Cobbs]

something like this? (screenshot from LDPE edited with paint)

the addition itself:
t08o800 like the existing syntax
the +/- indicates from where to start
the number states how far to go (+100 would be the same as a -100, a full quarter, no suffix needed then)

usage:
could be useful for chamfers or partially prints
if a torus gets cut somewhere
-> could still apply to prim subst

I know this is old, but Willy asked me to comment on this. So I have some comments.

First of all, I would obviously have to update LDView's primitive substitution in order to support this, but it doesn't look like the update would be too difficult.

Having said that, I don't like your proposed suffixes, for two reasons. First, I feel that using 05 for 50% and 075 for 75% just makes things confusing for anyone trying to understand what is going on. Furthermore, unless I'm misunderstanding, the numbers will always be less than 100%, so the 0 prefix also doesn't seem to make sense.

However, while percentages work fine for standard tori, they won't work for arbitrary fractions of 48 tori, since instead of 4 segments (25, 50, 75), there are 12, and 1/12 = 8.333333% (repeating fraction). It's true that we could use three digits (250, 500, 750), and then assume repeating for 083 and 166, but I feel that that would just complicate things further. One option would be to use a four-digit suffix, where the first two digits are the numerator and the second two are the denominator: 0104 for 1/4, 0102 for 1/2, 0204 for 3/4, 0112 for 1/12, 1112 for 11/12, etc.

I'm open to other suggestions, but I don't fell that a percent based number is a good idea. I'm fine the the + and -.

[Willy Tschager]

I know this is old, but Willy asked me to comment on this. So I have some comments.

First of all, I would obviously have to update LDView's primitive substitution in order to support this, but it doesn't look like the update would be too difficult.

Having said that, I don't like your proposed suffixes, for two reasons. First, I feel that using 05 for 50% and 075 for 75% just makes things confusing for anyone trying to understand what is going on. Furthermore, unless I'm misunderstanding, the numbers will always be less than 100%, so the 0 prefix also doesn't seem to make sense.

However, while percentages work fine for standard tori, they won't work for arbitrary fractions of 48 tori, since instead of 4 segments (25, 50, 75), there are 12, and 1/12 = 8.333333% (repeating fraction). It's true that we could use three digits (250, 500, 750), and then assume repeating for 083 and 166, but I feel that that would just complicate things further. One option would be to use a four-digit suffix, where the first two digits are the numerator and the second two are the denominator: 0104 for 1/4, 0102 for 1/2, 0204 for 3/4, 0112 for 1/12, 1112 for 11/12, etc.

I'm open to other suggestions, but I don't fell that a percent based number is a good idea. I'm fine the the + and -.

I recently started breaking that 8.3 nomenclature:

https://library.ldraw.org/parts/45361 (2-4chrd-w-edge.dat)

in the hope for more meaningful file names. Please consider leaving all cryptic name standards behind. As of the + and - I just found out that "+" works well in an editor like LDPE, but you cannot download a part from the PT with a "+" in the file name, so that would have to be fixed first

w.

[Orion Pobursky]

"+" isn't a URL friendly character since it has meaning in a URL much like "&", "#", and "/"

[Hageta]

"+"  in search a engine url is used as the space character (" ").

[Peter Blomberg]

What about updating the naming as follows?

sweep:

first number states the number of segments
second number states the resolution (8, 16, 48)

1-8
11-16
11-48
8-8, 16-16, and 48-48 would be full circles in different resolution

tori:
major sweep + "t" + major radius + "i"/"o"/"p"/"q"/"t" + minor sweep + "m" + minor radius

The 'i'nner starts from major-minor
The 'o'uter starts from major+minor
The 'p'erpendicular starts from major and continues inwards (toward major-minor)
The 'q' starts from major and continues outwards (toward major+minor)
A 't' contains the whole tube (2 inner + 2 outer) (minor sweep and "m" not needed)

cones and rings:
major sweep + "con" + major radius (minor assumed 1)
major sweep + "ring" + major radius (minor assumed 1)

cyls:
"cyls" major sweep + "i"/"o"/"p"/"q" + major radius
i starts from the low end, currently cyls
o starts from the high end
p starts from the middle and continues toward the low end, currently cyls2
q starts from the middle and continues toward the high end

spheres:
"sphe" major sweep + "i"/"o" + minor sweep
i starts from pole
o starts from equator (where major sweep is defined)

the "one-eight" of a sphere would be sphe4-16o4-16
a shallow puddle would be sphe16-16i1-16