the approach that I suggested puts the points in the correct plane, and in the correct position, in one step.

You make it sound like doing it in one step is a panacea. It isn't.

For example, if you are modeling planet gears rotating around a sun gear, you cannot combine the counter-rotations in to single matrix. And if the sub gear is not centred at the view origin, then additional discrete steps are required.

And there many other situations where the the individual parts of a combined transform have to be applied as discrete steps--in the right order--to achieve the final effect. Another example that comes to mind is when you have to translate a set of points to the origin before applying scaling in order to avoid distorting their relative positions.

As I said before, it is better to understand the discrete steps before attempting to combine them.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
RIP PCW

In reply to Re^9: (OT) moving points from one plane to another by BrowserUk
in thread (OT) moving points from one plane to another by merrymonk

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