How to make a 2D sphere with decreasing radial gradient

Clash Royale CLAN TAG#URR8PPP

up vote
2
down vote

favorite

I'm using this code:

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color = gray!60] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

which creates:

How to apply decreasing radial gradient?

The intended result would be something like (with the axes, etc remaining visible):

tikz-pgf tikz-3dplot

share|improve this question

edited 3 hours ago

asked 4 hours ago

Ziezi

235312

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Do you want the axes also to "fade away" or only the sphere?
  – marmot
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Only the sphere.
  – Ziezi
  3 hours ago
  

  
  
  
  

add a comment | 

up vote
2
down vote

favorite

I'm using this code:

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color = gray!60] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

which creates:

How to apply decreasing radial gradient?

The intended result would be something like (with the axes, etc remaining visible):

tikz-pgf tikz-3dplot

share|improve this question

edited 3 hours ago

asked 4 hours ago

Ziezi

235312

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Do you want the axes also to "fade away" or only the sphere?
  – marmot
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Only the sphere.
  – Ziezi
  3 hours ago
  

  
  
  
  

add a comment | 

up vote
2
down vote

favorite

up vote
2
down vote

favorite

I'm using this code:

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color = gray!60] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

which creates:

How to apply decreasing radial gradient?

The intended result would be something like (with the axes, etc remaining visible):

tikz-pgf tikz-3dplot

share|improve this question

edited 3 hours ago

asked 4 hours ago

Ziezi

235312

I'm using this code:

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color = gray!60] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

which creates:

How to apply decreasing radial gradient?

The intended result would be something like (with the axes, etc remaining visible):

tikz-pgf tikz-3dplot

tikz-pgf tikz-3dplot

share|improve this question

edited 3 hours ago

asked 4 hours ago

Ziezi

235312

share|improve this question

edited 3 hours ago

asked 4 hours ago

Ziezi

235312

share|improve this question

share|improve this question

edited 3 hours ago

edited 3 hours ago

edited 3 hours ago

asked 4 hours ago

Ziezi

235312

asked 4 hours ago

Ziezi

235312

asked 4 hours ago

Ziezi

235312

235312

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Do you want the axes also to "fade away" or only the sphere?
  – marmot
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Only the sphere.
  – Ziezi
  3 hours ago
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Do you want the axes also to "fade away" or only the sphere?
  – marmot
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Only the sphere.
  – Ziezi
  3 hours ago
  

  
  
  
  

Do you want the axes also to "fade away" or only the sphere?
– marmot
3 hours ago

Do you want the axes also to "fade away" or only the sphere?
– marmot
3 hours ago

Only the sphere.
– Ziezi
3 hours ago

Only the sphere.
– Ziezi
3 hours ago

add a comment | 

2 Answers
2

active

oldest

votes

up vote
3
down vote

If you want only a radial fading, then the example just before section 23.4.2 may be the way to go.

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 fill[tdplot_screen_coords,gray!40!black,%ball color = gray,
 path fading=fade out] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

Another option is to slightly slightly modify the fuzzy circles from the shadings library. (I merely copied and slightly modified the fuzzy circle fading from the library to give you immediate access to the transparency levels at different distances. I am not claiming that my choice is particularly nice, but in the end you need to decide yourself what suits you best. The number 23 does not really represent a percentage, but if you play basketball you may understand why I picked it. ;-)

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
makeatletter
pgfdeclareradialshadingtikz@lib@fade@circle@23pgfpointorigin
 color(0pt)=(pgftransparent!0); color(20bp)=(pgftransparent!50);
 color(25bp)=(pgftransparent!92); color(50bp)=(pgftransparent!100)
pgfdeclarefadingcircle with fuzzy edge 23 percentpgfuseshadingtikz@lib@fade@circle@23
makeatother
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color=gray!60,
 path fading=circle with fuzzy edge 23 percent] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

share|improve this answer

edited 2 hours ago

answered 3 hours ago

marmot

60.2k464131

add a comment | 

up vote
1
down vote

replace the shade line with

`node[circle,shading=radial,outer color=gray!30,inner color=black!80, minimum width=14.5cm];

share|improve this answer

edited 3 hours ago

answered 3 hours ago

KJO

1608

add a comment | 

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
3
down vote

If you want only a radial fading, then the example just before section 23.4.2 may be the way to go.

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 fill[tdplot_screen_coords,gray!40!black,%ball color = gray,
 path fading=fade out] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

Another option is to slightly slightly modify the fuzzy circles from the shadings library. (I merely copied and slightly modified the fuzzy circle fading from the library to give you immediate access to the transparency levels at different distances. I am not claiming that my choice is particularly nice, but in the end you need to decide yourself what suits you best. The number 23 does not really represent a percentage, but if you play basketball you may understand why I picked it. ;-)

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
makeatletter
pgfdeclareradialshadingtikz@lib@fade@circle@23pgfpointorigin
 color(0pt)=(pgftransparent!0); color(20bp)=(pgftransparent!50);
 color(25bp)=(pgftransparent!92); color(50bp)=(pgftransparent!100)
pgfdeclarefadingcircle with fuzzy edge 23 percentpgfuseshadingtikz@lib@fade@circle@23
makeatother
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color=gray!60,
 path fading=circle with fuzzy edge 23 percent] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

share|improve this answer

edited 2 hours ago

answered 3 hours ago

marmot

60.2k464131

add a comment | 

up vote
3
down vote

If you want only a radial fading, then the example just before section 23.4.2 may be the way to go.

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 fill[tdplot_screen_coords,gray!40!black,%ball color = gray,
 path fading=fade out] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

Another option is to slightly slightly modify the fuzzy circles from the shadings library. (I merely copied and slightly modified the fuzzy circle fading from the library to give you immediate access to the transparency levels at different distances. I am not claiming that my choice is particularly nice, but in the end you need to decide yourself what suits you best. The number 23 does not really represent a percentage, but if you play basketball you may understand why I picked it. ;-)

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
makeatletter
pgfdeclareradialshadingtikz@lib@fade@circle@23pgfpointorigin
 color(0pt)=(pgftransparent!0); color(20bp)=(pgftransparent!50);
 color(25bp)=(pgftransparent!92); color(50bp)=(pgftransparent!100)
pgfdeclarefadingcircle with fuzzy edge 23 percentpgfuseshadingtikz@lib@fade@circle@23
makeatother
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color=gray!60,
 path fading=circle with fuzzy edge 23 percent] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

share|improve this answer

edited 2 hours ago

answered 3 hours ago

marmot

60.2k464131

add a comment | 

up vote
3
down vote

up vote
3
down vote

If you want only a radial fading, then the example just before section 23.4.2 may be the way to go.

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 fill[tdplot_screen_coords,gray!40!black,%ball color = gray,
 path fading=fade out] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

Another option is to slightly slightly modify the fuzzy circles from the shadings library. (I merely copied and slightly modified the fuzzy circle fading from the library to give you immediate access to the transparency levels at different distances. I am not claiming that my choice is particularly nice, but in the end you need to decide yourself what suits you best. The number 23 does not really represent a percentage, but if you play basketball you may understand why I picked it. ;-)

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
makeatletter
pgfdeclareradialshadingtikz@lib@fade@circle@23pgfpointorigin
 color(0pt)=(pgftransparent!0); color(20bp)=(pgftransparent!50);
 color(25bp)=(pgftransparent!92); color(50bp)=(pgftransparent!100)
pgfdeclarefadingcircle with fuzzy edge 23 percentpgfuseshadingtikz@lib@fade@circle@23
makeatother
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color=gray!60,
 path fading=circle with fuzzy edge 23 percent] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

share|improve this answer

edited 2 hours ago

answered 3 hours ago

marmot

60.2k464131

If you want only a radial fading, then the example just before section 23.4.2 may be the way to go.

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 fill[tdplot_screen_coords,gray!40!black,%ball color = gray,
 path fading=fade out] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

Another option is to slightly slightly modify the fuzzy circles from the shadings library. (I merely copied and slightly modified the fuzzy circle fading from the library to give you immediate access to the transparency levels at different distances. I am not claiming that my choice is particularly nice, but in the end you need to decide yourself what suits you best. The number 23 does not really represent a percentage, but if you play basketball you may understand why I picked it. ;-)

documentclass[a4paper]article
usepackagetikz 
usepackagetikz-3dplot 
usetikzlibraryfadings
makeatletter
pgfdeclareradialshadingtikz@lib@fade@circle@23pgfpointorigin
 color(0pt)=(pgftransparent!0); color(20bp)=(pgftransparent!50);
 color(25bp)=(pgftransparent!92); color(50bp)=(pgftransparent!100)
pgfdeclarefadingcircle with fuzzy edge 23 percentpgfuseshadingtikz@lib@fade@circle@23
makeatother
tikzfading[name=fade out,
inner color=transparent!0,
outer color=transparent!100]

begindocument
 tdplotsetmaincoords45135
 pgfmathsetmacrorvec.8
 pgfmathsetmacrothetavec45
 pgfmathsetmacrophivec75

 begintikzpicture[scale=9,tdplot_main_coords]
 shade[tdplot_screen_coords,ball color=gray!60,
 path fading=circle with fuzzy edge 23 percent] (0,0) circle (rvec);
 coordinate (O) at (0,0,0);
 tdplotsetcoordPrvecthetavecphivec

 draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]$x$;
 draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]$y$;
 draw[thick,->] (0,0,-1) -- (0,0,1) node[anchor=south]$z$;
 draw[-stealth,color=black] (O) -- (P) node[midway,above] $r$;
 draw[dashed, color=red] (O) -- (Pxy);
 draw[dashed, color=red] (P) -- (Pxy);
 tdplotdrawarc(O)0.20phivecanchor=north$phi$

 tdplotsetthetaplanecoordsphivec
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)0.5thetavec90anchor=south west$theta$
 tdplotdrawarc[tdplot_rotated_coords](0,0,0)rvec-180180anchor=south west
 endtikzpicture 
enddocument

share|improve this answer

edited 2 hours ago

answered 3 hours ago

marmot

60.2k464131

share|improve this answer

share|improve this answer

edited 2 hours ago

edited 2 hours ago

edited 2 hours ago

answered 3 hours ago

marmot

60.2k464131

answered 3 hours ago

marmot

60.2k464131

answered 3 hours ago

marmot

60.2k464131

60.2k464131

add a comment | 

add a comment | 

up vote
1
down vote

replace the shade line with

`node[circle,shading=radial,outer color=gray!30,inner color=black!80, minimum width=14.5cm];

share|improve this answer

edited 3 hours ago

answered 3 hours ago

KJO

1608

add a comment | 

up vote
1
down vote

replace the shade line with

`node[circle,shading=radial,outer color=gray!30,inner color=black!80, minimum width=14.5cm];

share|improve this answer

edited 3 hours ago

answered 3 hours ago

KJO

1608

add a comment | 

up vote
1
down vote

up vote
1
down vote

replace the shade line with

`node[circle,shading=radial,outer color=gray!30,inner color=black!80, minimum width=14.5cm];

share|improve this answer

edited 3 hours ago

answered 3 hours ago

KJO

1608

replace the shade line with

`node[circle,shading=radial,outer color=gray!30,inner color=black!80, minimum width=14.5cm];

share|improve this answer

edited 3 hours ago

answered 3 hours ago

KJO

1608

share|improve this answer

share|improve this answer

edited 3 hours ago

edited 3 hours ago

edited 3 hours ago

answered 3 hours ago

KJO

1608

answered 3 hours ago

KJO

1608

answered 3 hours ago

KJO

1608

1608

add a comment | 

add a comment | 

 

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