Re: [office] right-angled-axes: was Re: [office] proposals for charts:reverse-direction, right-angled-axes, group-bars-per-axis

[Patrick Durusau <patrick@durusau.net>]

Lars,

I appreciate the 3d's team attempt to explain what they meant but I am 
afaid I am still lost. The explanation seems to make sense but it is 
dangling just out of reach.

Can you provide the citation for Foley et. al that is mentioned below? 
Perhaps if I can review some of the literature I will have a better 
understanding of the explanation.

Hope you are having a great day!

Patrick

Lars Oppermann wrote:

> Patrick Durusau wrote:
>
>>> Right-angled-axes
>>>  ...
>>>
>> Does this have the same effect as the dr3d:projection attribute found 
>> in 9.4.1 Scene?
>>
>> Noting that 9.4.1 is cited by the current 10.5.1.
>
>
> Here is some more explanation from the chart team...
>
> It's different in effect but related. Having dr3d:projection set to
> parallel makes 'parallel' lines. Setting chart:right-angled-axes to true
> should produce right angles.
> But in fact if setting right-angled-axes to true the values for
> dr3d:projection would be ignored.
> So one could think of expanding the values for dr3d:projection offering
> an additional value 'right-angled' or similar.
>
> dr3d:projection is parallel or perspective, the basic viewing modes for
> 3d projection (there are some more in the parallel tree, see Foley et
> al).
>  When You look at a 3d scene from the front and use non-rotated 
> objects, the Lines of the shapes which are parallel to X and Y 
> respectively will build a right angle in parallel and perspective 
> projection mode. I think the 'right-angled' has nothing to do with the 
> perspective projection mode, but with the orientations used in the 
> scene geometry itself. This is no new mode for perspective 
> projections. Remember: this is the mathematical projection between the 
> camera coordinate system and the
> 2d view coordinate system.
>
>

-- 
Patrick Durusau
Patrick@Durusau.net
Chair, V1 - Text Processing: Office and Publishing Systems Interface
Co-Editor, ISO 13250, Topic Maps -- Reference Model
Member, Text Encoding Initiative Board of Directors, 2003-2005

Topic Maps: Human, not artificial, intelligence at work!