"ingo" <ing### [at] tagpovrayorg> wrote in message 
news:Xns989EACFFCF424seed7@news.povray.org...
> in news:4587c656$1@news.povray.org Chris B wrote:
>
>> There was a discussion about whether people should be required to use
>> a standard size such as 1 POV-Ray unit = 1metre, but I think the
>> consensus was that this would difficult to apply universally because
>> very large scale (e.g. galaxies) and very small scales (atoms) can't
>> reasonably adhere to such a standard. Furthermore, someone who is
>> accustomed to working in Imperial measures could find it difficult to
>> think in Metric.
>>
>
> Sorry, I wasn't able to follow all the discussions recently, so my
> comment may have come up. Instead of standardising units why not require
> a "small scale object" to fit in a centerd 1x1x1 pov-unit cube. Then any
> user can scale the object to fit in a scene. For large scale objects one
> could recuire it to fit in a 100x100x100 unit box. Or require that the
> container for every object is defined in the #includefile (eventhough it
> can be figured out using min/max_extent)
>
> Thanks for the summary Chris.
>
> Ingo

Hi Ingo,

I think it was touched on in the thread, but I don't think it was discussed 
in detail.

Personally I think this would make life more complicated rather than less.

When I think of my POVPerson macros which generate characters of different 
sizes in different poses, if the macro scaled a 6ft tall seated person to 
fit in a fixed sized unit cube and then, on a second call to the macro it 
scaled a 5ft 4in standing person to fit in the same sized cube, I think it 
would make the characters quite difficult to use. The person using them 
would have to scale them up again by some quite difficult to calculate 
amounts to be able to use them together.

Even with something as simple as a cricket ball, you'd have to know the size 
of a cricket ball to scale it back to a realistic size if you just get a 
unit sized ball, whereas, if it's in a recognised unit of measure you'd 
probably be able to guess which conversion you need without even reading the 
accompanying documentation. IMO if you had a ball in metres and a set of 
cricket stumps in feet I think this would still be easier to work with than 
if you got them both scaled to fit in a unit square.

As soon as you get larger collections of objects I think the problem would 
grow. If each was scaled to a unit cube, then scaling them all by different 
amounts to get them to work together seems to me like it would be a real 
pain.

Regards,
Chris B.

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