[OpenSCAD] advanced openSCAD features and help

[Marius Kintel]

On Jan 7, 2010, at 05:29 , Loki wrote:

> I need some help and I've noticed that your not conforming to the  
> rather dazzling array of different ways of doing things with  
> graphics, so I'm hoping that your still in the process of pulling  
> out the stuff I need.
>
Please point out anything you feel is not conforming to common  
practices. Things can change ;)

> Ok, for starters, how do I apply a intersection operator over the  
> partial results of a for loop?

Use intersection_for() instead of for()

> Also, the [3,n] in the zero indexed matrix column doesn't perform  
> shearing like I expected. AFAIK it doesn't do anything.
>
This is due to a row-major vs. column-major matrix ordering.
Shearing is set by modifying the _last_ vector of the matrix instead  
of the last item of each vector.

> My real goal is I have a cylinder object, and I want to maintain the  
> bottom radius and gradually pinch the x axis together into a  
> parabolic smooth shape, and elongate the y axis. The purpose is to  
> make a hinge attached to a cylinder.
>
I didn't quite get that (time to go to sleep;), so please post the  
object if you get it modeled as you want!

Cheers,

~/= Marius

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