Le 11/12/2014 09:34, omniverse a écrit :
> "Anthony D. Baye" <Sha### [at] spamnomorehotmailcom> wrote:
>> f_helix1(x,y,z,n,p,r,R,s,c,a)
>> supposedly, the fifth parameter is the period, or "Number of turns per unit
>> length".
>>
>> The way I read this is that, for every unit the helix object rises, it should
>> make one complete turn.  This is obviously not the case.
> 
> Anthony, I can confirm same here.
> 
> Slightly different wording found in the Insert menu, Special shapes|Isosurfaces
> by function.inc and placing the Isosurface f_helix into a scene file, so I went
> looking for the source code after realizing it was essentially saying the number
> of turns is based on a complete circle. Meaning if you apply that 2*pi to your
> number of turns you should get what you expected. I checked this and seemed to
> work.
> 
> Source code makes very little sense to me, although a coding math wizard
> probably could get the 2*pi introduced into there somehow.
> 
> You can look it over yourself at (line 519):
> 
> https://github.com/POV-Ray/povray/blob/3.7-stable/source/backend/vm/fnintern.cpp
> 
> Guessing it's the r or r2 variables which would require the 2*pi to complete
> whole turns for the "period" parameter.
> 
> Looking at the online documentation, almost halfway down page at:
> 
> http://www.povray.org/documentation/view/3.7.0/448/
> 
> I see it also says "related" to number of turns, suggesting again it wasn't
> actually made to do a user-specified amount.
> Interesting thing, if not, because I would have thought same as you did.
> 
> 
> 

So, it is per radian rather than per turn ?

-- 
Just because nobody complains does not mean all parachutes are perfect.

Post a reply to this message