ma...@mendelu.cz wrote:
> I think that parametric plot could work in this simple example.
>
>
> r,phi,y=var('r phi y')
> A=parametric_plot3d([r*cos(phi)+2,r*sin(phi)+3,(r*cos(phi)+2)^2+(r*sin
> (phi)+3)^2],(r,0,2),(phi,0,2*pi),opacity=0.9)
> B=parametric_plot3d([r*cos(phi)+2,r*sin(phi)+3,0],(r,0,2),(phi,
> 0,2*pi),rgbcolor='red')
> C=plot3d(x^2+y^2,(x,-6,6),(y,-6,6),opacity=0.1,rgbcolor='green')
> show(A+B+C)
>
>
Gotta love cylindrical coordinates!
Of course, making the domain slightly harder makes this more complicated
fast. :)
I don't think there is the analogue to the "RegionFunction" stuff in
Mathematica in our plot3d, at least yet:
http://reference.wolfram.com/mathematica/ref/RegionFunction.html
I'm not sure how hard it would be to add one; it would involve figuring
out how to clip triangles, separate a 3d plot into separate pieces,
etc., I think.
Jason
> Robert
>
>
>
> On 11 Bře, 05:32, Rob Beezer <goo...@beezer.cotse.net> wrote:
>
>> Hi Carl,
>>
>> Yes, I meant over the interior. ;-) Thanks for the explanation of
>> what's coming in implicit_plot3d() - sounds like it will be a good
>> addition.
>>
>>
>>>> In other words, could I plot x^2+y^2 *only* above the circle (x-2)^2 +
>>>> (y-3)^2=4?
>>>>
>>> Of course, implicit_plot3d is a bad way to plot this function, because
>>> it will be far slower than plot3d.
>>>
>> Am I missing a way to plot this function, so I only see the portion
>> above (the interior of) the circle, by using plot3d()?
>>
>> Rob
>>
> >
>
>
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