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Fill Surface the Curve ?

lvl107
20-Turquoise

Fill Surface the Curve ?

  Hello Everyone,

From:

Fill_Surface_Curve.PNG

  How to Fill Surface the Blue Curve ?

  Thanks in advance for your time and help.

  Regards.

ACCEPTED SOLUTION

Accepted Solutions
Werner_E
25-Diamond I
(To:Werner_E)

You can do the same thing by showing the parameter lines for constant t-values. These are straight lines.

So we now clearly recognise the two sets of straight lines on this HP surface (hyperbolic paraboloid), which is therefore a two-fold ruled surface.

Paraboloid - Wikipedia

Ruled surface - Wikipedia

ani2.gif

BTW. the equation of this surface in kartesian coordinates is z(x,y):=x*y.

This said you could also parametrise this surface that way:

Werner_E_0-1742886569194.png

 

But, at the risk of repeating myself, this HP surface is just one of an infinite number of possible surfaces... 😉

Here is a last one, a cone:

Werner_E_0-1742916137100.png

 

 

View solution in original post

11 REPLIES 11
Werner_E
25-Diamond I
(To:lvl107)

You would first have to define a surface function.

A surface is not defined just by the surrounding curve.

You may ask for the minimal surface but I guess this would turn into a hard job to do...    Minimal surface - Wikipedia

 

I don't know which kind of surface Mathcad is creating when you do a surface plot of S - do you know it? 😉

 

Here are three out an infinite number of possible surfaces which includes your curve:

Werner_E_0-1742856833519.png

 

 

 

lvl107
20-Turquoise
(To:Werner_E)


@Werner_E wrote:

Here are three out an infinite number of possible surfaces which includes your curve:

 Many thanks, Werner. 🙄 🤔 😊. I guess it seems an infinite number of possible surfaces which DOES NOT includes the question's request :

 

I.png

II.PNG

III.png

 

Best Regards.

 

 

 


 

Werner_E
25-Diamond I
(To:lvl107)


@lvl107 wrote:

I guess it seems an infinite number of possible surfaces which DOES NOT includes the question's request :


Nonetheless an infinite number of surfaces does - three examples were given. Thats simply because your "request" only was " How to Fill Surface the Blue Curve ?" This did not make much sense anyway as a simple curve does not define a surface. That said any surface containing your curve can be seen as a solution to your request. If you had a specific surface in mind you should  have had to say so clearly.

 

BTW, I don't think that what you posted now - just a couple of numbers in nested matrix SS will be of any value without showing where they may stem from. What exactly are you trying to achieve with this?

What you sell as surface by connecting/meshing some precalculated points of your curve may be an approximation of another one of the infinite number of solutions 😉

 

For future question please be (much) more specific as to what exactly you are REALLY looking for. It could save some of us empty miles...

 

BTW, it looks to me like you could achieve the very same surface you show much simpler that way:

Werner_E_0-1742874816800.png

Simply connecting points with equal y coordinates.

You could as well connect the points with equal x coordinates

Werner_E_1-1742875207806.png

The difference lies in the parameterisation.
The animation allows the second parameter u to vary. The colours are, as is unfortunately usual with AVIs generated by Mathcad, suboptimal.

ani.gif

lvl107
20-Turquoise
(To:Werner_E)

  Thanks again, Werner. Your answer is very neat to me. 🙄 🤔 😊 But in the amination, What are S4 and S5 ? So, Please attach the .xmcd file.

    Best Regards.

Werner_E
25-Diamond I
(To:lvl107)

S4 resp. S5 are the surface curves with a constant parameter u.

Werner_E_0-1742883059476.png

U runs from 0 to 1

Werner_E
25-Diamond I
(To:Werner_E)

You can do the same thing by showing the parameter lines for constant t-values. These are straight lines.

So we now clearly recognise the two sets of straight lines on this HP surface (hyperbolic paraboloid), which is therefore a two-fold ruled surface.

Paraboloid - Wikipedia

Ruled surface - Wikipedia

ani2.gif

BTW. the equation of this surface in kartesian coordinates is z(x,y):=x*y.

This said you could also parametrise this surface that way:

Werner_E_0-1742886569194.png

 

But, at the risk of repeating myself, this HP surface is just one of an infinite number of possible surfaces... 😉

Here is a last one, a cone:

Werner_E_0-1742916137100.png

 

 

lvl107
20-Turquoise
(To:Werner_E)

   Werner, could you help me with downloading GIF converter. My .AVI file has size too big ( 13 MB ).

 

  Thanks again, Werner.

  Best Regards.

Werner_E
25-Diamond I
(To:lvl107)


@lvl107 wrote:

   Werner, could you help me with downloading GIF converter. My .AVI file has size too big ( 13 MB ).

??? Not sure what the problem is. Your video seems to work OK anyway?

As for AVI  to GIF - there are a lot of online converters out there, just use a search engine.

Some examples:

AVI to GIF | CloudConvert

AVI to GIF Converter

AVI in GIF Umwandeln

....

 

lvl107
20-Turquoise
(To:Werner_E)

 I go to AVI to GIF | CloudConvert, and converting .AVI to GIF. The .GIF file has only made up 5.5 MB. Once  again, many, many thanks, Werner. 😊 😊 😊

 

  I am going to hope the video is going to have the same quality.  

Best Regards.  

lvl107
20-Turquoise
(To:Werner_E)

   Werner, following your hint: ( F6(r , phi) ), the above then:

0.PNG1.PNG2.PNG

  I really don't know the reason, the above.

    Regards. 

Werner_E
25-Diamond I
(To:lvl107)

I don't understand why you are concerned!?

Using the quickplot feature requires you to set the limits in the plot format dialog. If you keep the default values (from -5 to 5) the surface is plotted multiple times and because you used 1/5 in your function definition the surface extends just to the outer blue line.

More reasonable values would be:

Werner_E_0-1743021318733.png

Its easier to apply these values in the CreateMesh function which is the reason why I prefer it over the quickplot.

Another reason for using CreateMesh is that you can't use variables in the Plot Format menu and so are limited when making animations like this:

ani.gif

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