Modelling question: How to specific a reference point when rotating

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Modelling question: How to specific a reference point when rotating

Laszlo KREKACS
Hi!

Do somebody know, how can I specify a reference point in the modelling space,
so the point around the object should turn and not always the origo.

The lack of my knowledge here makes really frustrating, as I need to
turn two times
the object, and I cant turn around the origo the second time.

I solved by trial-and-error positioning after, but I could get rid of
it, if I were know the feature
beforehand.

Best regards,
 Laszlo

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Re: Modelling question: How to specific a reference point when rotating

kintel
Administrator

On Jan 30, 2010, at 17:43 , Laszlo KREKACS wrote:

> Hi!
>
> Do somebody know, how can I specify a reference point in the  
> modelling space,
> so the point around the object should turn and not always the origo.
>
The rotate() module always rotates an object around its origin.
To rotate around another point, make this point the origin, perform  
the rotation and translate the object back:

midpoint = [5,10];
translate(midpoint) rotate([0,0,45]) translate(-midpoint)  
square(size=[10,20]);

If your object comes from dxf you can specify the origin, but you  
still need to move it back:

origin = [100,100];
translate(origin) rotate([0,0,45]) import_dxf(file="origin.dxf",  
origin=origin);

You can extract the origin from the dxf by using the dxf_cross()  
module to read out the position of a manually drawn cross in the dxf  
file. This is demoed in the example009.

~/= Marius

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