"Rune" <run### [at] runevisioncom> wrote in news:3f60a3af@news.povray.org:

> Marc Champagne wrote:
>> Would it not be wise for the scale statement
>> to assume 1 instead of 0 for those vectors
>> that are not specified.
> 
> The following may sound like nitpicking, but I think it's worth
> mentioning.
> 
> When you scale by x*2 then you are not just specifying the x-scaling,
> you are also specifying the y-scaling and z-scaling. These you have set
> to 0.
> 
> This is not because 0 is any kind of default. It is simply because the
> meaning of the build-in variable "x" is exactly <1,0,0>. That is, "x" is
> a full vector in itself, not some kind of float that only applies to the
> x value. So when you are specifying scale x*2 then it is exactly the
> same as specifying scale <1,0,0>*2 and this is a full vector definition,
> without any defaults being assumed.
> 
> I still think it's a good idea that POV-Ray corrects the incorrect
> scaling specifications, but the warning definitely should be there.
> 
> My main point I guess, is to make clear that no default are being
> assumed, since there are no vectors that are "not being specified", and
> thus it doesn't make sense to request that the defaults should be
> different.

Well your nitpicking :) makes a whole lot of sense, I better understand
now! 

What frustrates me the most are sequences that are not so obvious without
mentaly breaking it down, such as 
    	
    	scale x * 2 + y + 15 * z

I still believe for this case that

    	scale (x * 2) + (y * 1) + (15 * z)

or even better

    	scale <2,1,15>

would be faster to digest by humans (more readable)


Thanks

-- 
Marc Champagne
marcch.AT.videotron.DOT.ca
Montreal, CANADA

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