This the code I draw the circle center at `G` and radius `radius = \myr`. I get the circle, but dashed behind the circle incorrect. ``` \documentclass[12pt]{standalone} \usepackage{tikz,tikz-3dplot} \usetikzlibrary{fpu,calc} \usepackage{tikz-3dplot-circleofsphere} \def\pgfmathsetmacroFPU#1#2{\begingroup% \pgfkeys{/pgf/fpu,/pgf/fpu/output format=fixed}% \pgfmathsetmacro{#1}{#2}% \pgfmathsmuggle#1\endgroup}% \begin{document} \tdplotsetmaincoords{70}{70} \begin{tikzpicture}[tdplot_main_coords,line cap=butt,line join=round,c/.style={circle,fill,inner sep=1pt}, declare function={a=3;b=4;c=5;m=3;n=3;p=3;}] \begin{scope}[/pgf/fpu,/pgf/fpu/output format=fixed] \path (0,0,0) coordinate (A) (c,0,0) coordinate (B) ({(pow(b,2) + pow(c,2) - pow(a,2))/(2*c)},{sqrt((a+b-c) *(a-b+c) *(-a+b+c)* (a+b+c))/(2*c)},0) coordinate (C) ({c/2},{(c* (a^2 + b^2 - c^2))/(2* sqrt((a + b - c) *(a - b + c)* (-a + b + c)* (a + b + c)))},0) coordinate (G) ({(c^2 + m^2 - n^2)/(2*c)},{(-c^4 + (a^2 + b^2 + m^2 + n^2 - 2*p^2)*c^2 + (m - n)*(m + n)*(a - b)*(a + b))/(2*sqrt(-(a + b - c)*(a - b + c)*(a - b - c)*(a + b + c))*c)},{-1*sqrt((a - b + c)*(a - b - c)*(a + b + c)*(b^2*n^4 + ((a^2 - b^2 - c^2)*p^2 + (-b^2 + m^2)*c^2 + b^4 + (-a^2 - m^2)*b^2 - a^2*m^2)*n^2 + c^2*p^4 + (c^4 + (-a^2 - b^2 - m^2)*c^2 - a^2*m^2 + b^2*m^2)*p^2 + ((b^2 - m^2)*c^2 + m^2*(a^2 - b^2 + m^2))*a^2)*(a + b - c))/(a^4 - 2*a^2*b^2 - 2*a^2*c^2 + b^4 - 2*b^2*c^2 + c^4)}) coordinate (S) ( {c/2},{c*(a^2 + b^2 - c^2)/(2*sqrt(-(a + b - c)*(a - b + c)*(a - b - c)*(a + b + c)))},{-1*(a^4*m^2 + 2*a^2*b^2*c^2 - a^2*b^2*m^2 - a^2*b^2*n^2 - a^2*c^2*m^2 - a^2*c^2*p^2 + b^4*n^2 - b^2*c^2*n^2 - b^2*c^2*p^2 + c^4*p^2)/(2*sqrt((a^4 - 2*a^2*b^2 - 2*a^2*c^2 + b^4 - 2*b^2*c^2 + c^4)*(a^4*m^2 + a^2*b^2*c^2 - a^2*b^2*m^2 - a^2*b^2*n^2 - a^2*c^2*m^2 - a^2*c^2*p^2 + a^2*m^4 - a^2*m^2*n^2 - a^2*m^2*p^2 + a^2*n^2*p^2 + b^4*n^2 - b^2*c^2*n^2 - b^2*c^2*p^2 - b^2*m^2*n^2 + b^2*m^2*p^2 + b^2*n^4 - b^2*n^2*p^2 + c^4*p^2 + c^2*m^2*n^2 - c^2*m^2*p^2 - c^2*n^2*p^2 + c^2*p^4)))})coordinate (T); \pgfmathsetmacroFPU{\myr}{a*b*c/sqrt((b+c-a)* (a + b - c) *(a - b + c)* (a + b + c))} \pgfmathsetmacroFPU{\myR}{sqrt((a^4*m^4 - 2*m^2*(b^2*n^2 + c^2*p^2)*a^2 + b^4*n^4 - 2*b^2*c^2*n^2*p^2 + c^4*p^4)/(a^4*m^2 + ((c^2 - m^2 - n^2)*b^2 + (-m^2 - p^2)*c^2 + m^4 + (-n^2 - p^2)*m^2 + n^2*p^2)*a^2 + b^4*n^2 + ((-n^2 - p^2)*c^2 + (-n^2 + p^2)*m^2 + n^4 - n^2*p^2)*b^2 + c^2*(p^2*c^2 + (n^2 - p^2)*m^2 - n^2*p^2 + p^4)))/2} \pgfmathsetmacroFPU{\Angle}{acos(\myr/\myR)} \draw[tdplot_screen_coords] (T) circle [radius = \myR]; \draw [dashed] (A) -- (C) (S) --(G); \draw (S) -- (A) (S) -- (B) (S) -- (C) (A) -- (B) -- (C); \draw (G) circle [radius = \myr]; \end{scope} \path foreach \p/\g in {A/-90,B/-90,C/-90,S/90,G/-90,T/0}{(\p)node[c]{}+(\g:2.5mm) node{$\p$}}; \end{tikzpicture} \end{document} ```  I tried to draw a circle by using `tikz-3dplot-circleofsphere` (https://github.com/matthias-wolff/tikz-3dplot-circleofsphere). ``` \begin{scope}[shift={(T)}] \tdplotCsDrawLatCircle[blue, thick]{\myR}{\Angle} \end{scope} ``` ``` \documentclass[12pt]{standalone} \usepackage{tikz,tikz-3dplot} \usetikzlibrary{fpu,calc} \usepackage{tikz-3dplot-circleofsphere} \def\pgfmathsetmacroFPU#1#2{\begingroup% \pgfkeys{/pgf/fpu,/pgf/fpu/output format=fixed}% \pgfmathsetmacro{#1}{#2}% \pgfmathsmuggle#1\endgroup}% \begin{document} \tdplotsetmaincoords{70}{70} \begin{tikzpicture}[tdplot_main_coords,line cap=butt,line join=round,c/.style={circle,fill,inner sep=1pt}, declare function={a=3;b=4;c=5;m=3;n=3;p=3;}] \begin{scope}[/pgf/fpu,/pgf/fpu/output format=fixed] \path (0,0,0) coordinate (A) (c,0,0) coordinate (B) ({(pow(b,2) + pow(c,2) - pow(a,2))/(2*c)},{sqrt((a+b-c) *(a-b+c) *(-a+b+c)* (a+b+c))/(2*c)},0) coordinate (C) (barycentric cs:A=1,B=1,C=1) coordinate (G) ({(c^2 + m^2 - n^2)/(2*c)},{(-c^4 + (a^2 + b^2 + m^2 + n^2 - 2*p^2)*c^2 + (m - n)*(m + n)*(a - b)*(a + b))/(2*sqrt(-(a + b - c)*(a - b + c)*(a - b - c)*(a + b + c))*c)},{-1*sqrt((a - b + c)*(a - b - c)*(a + b + c)*(b^2*n^4 + ((a^2 - b^2 - c^2)*p^2 + (-b^2 + m^2)*c^2 + b^4 + (-a^2 - m^2)*b^2 - a^2*m^2)*n^2 + c^2*p^4 + (c^4 + (-a^2 - b^2 - m^2)*c^2 - a^2*m^2 + b^2*m^2)*p^2 + ((b^2 - m^2)*c^2 + m^2*(a^2 - b^2 + m^2))*a^2)*(a + b - c))/(a^4 - 2*a^2*b^2 - 2*a^2*c^2 + b^4 - 2*b^2*c^2 + c^4)}) coordinate (S) ( {c/2},{c*(a^2 + b^2 - c^2)/(2*sqrt(-(a + b - c)*(a - b + c)*(a - b - c)*(a + b + c)))},{-1*(a^4*m^2 + 2*a^2*b^2*c^2 - a^2*b^2*m^2 - a^2*b^2*n^2 - a^2*c^2*m^2 - a^2*c^2*p^2 + b^4*n^2 - b^2*c^2*n^2 - b^2*c^2*p^2 + c^4*p^2)/(2*sqrt((a^4 - 2*a^2*b^2 - 2*a^2*c^2 + b^4 - 2*b^2*c^2 + c^4)*(a^4*m^2 + a^2*b^2*c^2 - a^2*b^2*m^2 - a^2*b^2*n^2 - a^2*c^2*m^2 - a^2*c^2*p^2 + a^2*m^4 - a^2*m^2*n^2 - a^2*m^2*p^2 + a^2*n^2*p^2 + b^4*n^2 - b^2*c^2*n^2 - b^2*c^2*p^2 - b^2*m^2*n^2 + b^2*m^2*p^2 + b^2*n^4 - b^2*n^2*p^2 + c^4*p^2 + c^2*m^2*n^2 - c^2*m^2*p^2 - c^2*n^2*p^2 + c^2*p^4)))})coordinate (T); \pgfmathsetmacroFPU{\myr}{a*b*c/sqrt((b+c-a)* (a + b - c) *(a - b + c)* (a + b + c))} \pgfmathsetmacroFPU{\myR}{sqrt((a^4*m^4 - 2*m^2*(b^2*n^2 + c^2*p^2)*a^2 + b^4*n^4 - 2*b^2*c^2*n^2*p^2 + c^4*p^4)/(a^4*m^2 + ((c^2 - m^2 - n^2)*b^2 + (-m^2 - p^2)*c^2 + m^4 + (-n^2 - p^2)*m^2 + n^2*p^2)*a^2 + b^4*n^2 + ((-n^2 - p^2)*c^2 + (-n^2 + p^2)*m^2 + n^4 - n^2*p^2)*b^2 + c^2*(p^2*c^2 + (n^2 - p^2)*m^2 - n^2*p^2 + p^4)))/2} \pgfmathsetmacroFPU{\Angle}{acos(\myr/\myR)} \draw[tdplot_screen_coords] (T) circle [radius = \myR]; \draw [dashed] (A) -- (C) (S) --(G); \draw (S) -- (A) (S) -- (B) (S) -- (C) (A) -- (B) -- (C); \end{scope} \begin{scope}[shift={(T)}] \tdplotCsDrawLatCircle[blue, thick]{\myR}{\Angle} \end{scope} \path foreach \p/\g in {A/-90,B/-90,C/-90,S/90,G/-90,T/0}{(\p)node[c]{}+(\g:2.5mm) node{$\p$}}; \end{tikzpicture} \end{document} ```  I got incorrect circle.