alice-teacher How to orient part of an object to another object

[Don Slater]

"Point at" uses the forward axis of an object for alignment with the center point of the target object. It is not possible to change any of the axes of any object.

See the attached lighthouse.a2w file...

1) I added the axes from the shapes gallery to the world.
2) Set the point of view of the axes to the lighthouse
3) Moved the axes up 26 meters to set it at the peak of the lighthouse (its orientation is still the same as the lighthouse)
4) I turned the axes backward a quarter turn.
5) I set the vehicle of the lighthouse to the axes. Now the lighthouse will use the axes forward orientation in the point at command.

In my do together code
	I point the axes at the sphere (my target)
	move the axes to the sphere

I hope that this helps…

Please let me know if you have any questions.

Later,
Don Slater

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On Nov 24, 2011, at 4:29 PM, Findley, Scott wrote:

> Don,
> Still having issues with the axis. Here's a response from the student:
> 
> I want my lighthouse to point at the helicopter as seen by the light house's y axix (the green one) Currently, the point at is making the lighthouse point it's z or x axis (the red one) at the helicopter. How do I get the lighthouse's y axis to point at the helicopter regardless of where the helicopter is in the world?
> 
> Suggestions? Help? I've attached a copy of his Alice file.
> 
> 
> 
> Thanks,
> Mr. Scott Findley 
> sfindley at sd43.bc.ca
> Gleneagle Secondary School http://gleneagle.org
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> -----Original Message-----
> From: alice-teachers-bounces+sfindley=sd43.bc.ca at lists.andrew.cmu.edu [mailto:alice-teachers-bounces+sfindley=sd43.bc.ca at lists.andrew.cmu.edu] On Behalf Of Don Slater
> Sent: Thursday, November 24, 2011 6:16 AM
> To: Alice educators
> Subject: Re: alice-teacher How to orient part of an object to another object
> 
> You might take another object, perhaps something from the shapes gallery, put it at the tip of the lighthouse, set its "is showing" property to false, set its "vehicle" property to the lighthouse, and then the lighthouse movements can be based on the "as seen by" modifier referencing this invisible object.
> 
> Please let me know if you have any questions.
> 
> Later,
> Don Slater
> 
> On Nov 23, 2011, at 5:08 PM, Findley, Scott wrote:
> 
>> I have a student who wants to have the lighthouse 'launch' itself at a helicopter off in the distance, yet when he "Point at" a helicopter on the horizon, yet the lighthouse uses it's centre axis/point instead of the tip/point (much like a missile). Any suggestions?
>> 
>> 
>> 
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