.PS # FourbarSVG.m4 # https://tex.stackexchange.com/questions/563831/how-to-draw-four-bar-linkage-with-center-of-mass gen_init scale = 25.4 a = 18 b = 73 c = 47 d = 72 A0: Here B0: A0+(d,0) circlerad = 1 define(`pivot',`[ C: circle line down_ 4 from C+(2,0) arc from last line.start to C+(-2,0) with .c at C line down_ 4 B: line thick 1.6 right 7 with .c at (C,Here) thinlines_ sep = 0.9 nhash = B.len/sep #for i=0 to nhash do { line down sep left sep from B.start+(i/nhash*B.len,0) } for i=0 to nhash do { line down sep left sep from B.end-(i/nhash*B.len,0) } thicklines_ ]') pivot with .C at A0; "svg_it(A`'svg_sub(0))" at A0-(5,0) circle dashed rad a at A0 pivot with .C at B0; "svg_it(B`'svg_sub(0))" at B0-(5,0) "svg_it(d = A`'svg_sub(0)B`'svg_sub(0))" at 0.5 B1: Cintersect(A0,a+b,B0,c) B2: Cintersect(A0,b-a,B0,c) arc dashed from B1 to B2 with .c at B0 A0B1: line thick 1.6 from A0 to B1 chop 2 chop line thick 1.6 from B0 to B1 chop 2 chop "svg_it(c)" ljust circle fill_(1) at B1; "svg_it(B`'svg_sub(1))" wid 3 at B1+(5,0) A1: circle fill_(1) at LCintersect(A0B1,A0,a,R) "svg_it(A`'svg_sub(1))" at A1+(5,0) A2: b/(b-a) between B2 and A0; "svg_it(a)" at 0.4 above rjust "svg_it(b)" at 0.4 above rjust A2B2: line thick 1.6 from A2 to B2 line thick 1.6 from B0 to B2 chop 2 chop 0 circle fill_(1) at B2; "svg_it(B`'svg_sub(2))" at B2+(5,0) circle fill_(1) at A2; "svg_it(A`'svg_sub(2))" at A2+(5,0) thinlines_ line from B0+(3,0) right 4 ArcAngle(Here,B0,B1,5) ->; "svg_psi`'svg_sub(0)" at last arc.ne above ljust ArcAngle(B1,B0,B2,8) ->; "svg_psi" at last arc.n+(-3,0) above ArcAngle(A1,A0,B2,b*0.45) ->; "svg_theta" at last arc.start+(0,4) line from A0+(3,0) right 8 ArcAngle(Here,A0,B1,9) -> ; "svg_theta`'svg_sub(0)" at last arc.start+(2,2) .PE