Sstrhsrtj

Hi i try to plot a cylindrical domain, where the bottom of the cylinder is not a circle or ellipse.

My knowledge is very poor and all my previous attempts failed.

Failed attempt:

documentclass{article}

usepackage{tikz}

usepackage[active,tightpage]{preview}

PreviewEnvironment{tikzpicture}

begin{document}

begin{tikzpicture}



draw plot [smooth cycle] coordinates{(0,0) (1,-.5) (1.2,1.5) (0,1) (-.5,.5) (-.7,.2)};



draw plot [smooth cycle] coordinates{(3,2) (4,1.5) (4.2,3.5) (3,3) (2.5,2.5) (2.3,2.2)};





draw (1,-.5)--(4,1.5);



draw (1.2,1.5)--(4.2,3.5);



end{tikzpicture}

end{document}

There are many ways to visualize such a cylinder in TeX world, here is one made by means of
extrude feature of the Asymptote using raster output.

% cyl.tex :

%

documentclass{article}

usepackage[inline]{asymptote}

usepackage{lmodern}

begin{document}

begin{figure}

begin{asy}

settings.outformat="png";

settings.tex="pdflatex";

settings.render=8;

size(5cm);

import graph3;

import fontsize;

defaultpen(fontsize(9pt));



currentprojection=orthographic(camera=(3,3,6),up=Z,target=O,zoom=1);



currentlight=light(gray(0.8),ambient=rgb(0.1,0.099,0.101),specular=gray(0.7),

                     specularfactor=3,viewport=true,dir(42,48));



pair ppair={(0,0),(1,-.5),(1.2,1.5),(0,1),(-.5,.5),(-.7,.2)};

real height=3;



guide gbase=graph(ppair, Spline)..cycle;



pen bpen=rgb(0.1, 0.1, 0.8)+opacity(0.5);

material m=material(diffusepen=0.7bpen

,ambientpen=bpen,emissivepen=0.3*bpen,specularpen=0.999white,shininess=1.0);



draw(rotate(-90,Y)*rotate(180,Z)*extrude(gbase,height*Z),m,render(merge=true));



xaxis3("$x$",-3.2,1.2,red  ,Arrow3);

yaxis3("$y$",  -2,2,green,Arrow3);

zaxis3("$z$",  -3,3,blue ,Arrow3);



end{asy}

end{figure}

end{document}

%

% Process:

%

% pdflatex cyl.tex    

% asy cyl-*.asy    

% pdflatex cyl.tex

It looks like you could use pgfplots for this, e.g.:

Code

documentclass[tikz,border=2mm]{standalone}

usepackage{pgfplots}

pgfplotsset{compat=1.8}



begin{document}



begin{tikzpicture}

    begin{axis}

    [ z buffer=sort,

    ]

        addplot3[domain=0:360,y domain=0:360,surf,shader=faceted,samples=40]

        ( {cos(y)+0.1*sin(7*y)},

            {x},

            {sin(y)+0.1*cos(3*y)}

        );

    end{axis}

end{tikzpicture}



end{document}

Output

A function for the base is also possible.

documentclass[pstricks,border=12pt]{standalone}

usepackage{pst-solides3d}

begin{document}



psset{viewpoint=50 -20 40 rtp2xyz, Decran=50,linearc=0.2}

begin{pspicture}(-1,-1)(4,4)

psSolid[object=prisme,axe=0 0.5 1,

base= 0 0 1 -.5 1.2 1.5 0 1 -.5 .5 -.7 .2 ,

linecolor=red,h=4,action=draw*]

end{pspicture}



begin{pspicture}(-1,-1)(4,4)

psSolid[object=prisme,axe=0 0.5 1,

base= 0 0 1 -.5 1.2 1.5 0 1 -.5 .5 -.7 .2 ,

hollow,fillcolor=red!30,incolor=blue!30,

linecolor=red,h=4,action=draw**]%

end{pspicture}



end{document}