Playground

asset pendulum_blade "Pendulum blade" complexity=4
// a corridor trap: a heavy timber gantry with iron brackets straddles the passage, and from its
// beam a long iron arm swings a huge crescent blade side to side, a hair above the floor. A cog
// on the pivot turns with it, a skull rides the blade's hub. Fits a 4 m passage; it faces +z.
let W = 1.62
let woodC = walnut:2|oak|redwood
let ironC = iron:3|inkDark
let edgeC = silver:2|steel|white
 
// the gantry: two posts on stone feet, a beam, corner braces
box foot at=(W, 0, 0) mirror size=(.5, .3, .5) round=.06 bev=2 color=greystone
box post on=foot at=(0, .25, 0) size=(.3, 3.3, .3) round=.05 bev=2 stripes=[woodC woodC*.85] panels=3 color=woodC
box beam at=(0, 3.45, 0) size=(2*W+.5, .34, .36) round=.06 bev=2 stripes=[woodC woodC*.85] panels=8 color=woodC
rod brace on=post at=(-.12, 2.6, 0) to=(-.65, .7, 0) r=.07 sides=10 color=woodC
box bracket on=post at=(0, 3.05, 0) size=(.36, .3, .4) round=.03 bev=2 color=ironC
ball bolt x2 on=bracket at=(0, .15, .2) row=(.2, 0, 0) r=.035 color=ironC*1.4 segs=6 rings=4
 
// the pivot, its cog and the swinging arm
cyl hubPlate on=beam at=(0, .17, .17) rot=(90, 0, 0) h=.05 r=.3 color=ironC segs=20
cyl cog on=beam at=(0, .17, .21) rot=(90, 0, 0) h=.08 r=.17 color=brass segs=14 joint
cone tooth x10 on=cog ring at=(.17, .04, 0) rot=(0, 0, -90) h=.08 r=.05 color=brass segs=4
ball pivot on=beam at=(0, .17, .33) r=.11 color=brass segs=12 rings=8 joint
rod arm on=pivot at=(0, 0, 0) to=(0, -2.62, 0) r=.06 sides=12 color=ironC
ball hub on=arm at=end r=.15 color=ironC segs=14 rings=9
ball skull on=hub at=(0, 0, .1) r=(.12, .11, .1) color=cream segs=12 rings=8
ball socket on=skull at=(.045, .02, .08) mirror r=(.032, .036, .025) color=inkDark ink=none segs=6 rings=4
slab blade on=hub at=(0, .12, -.03) pts=[-.7,-.2 -.48,-.55 0,-.72 .48,-.55 .7,-.2 .5,0 .32,-.24 0,-.34 -.32,-.24 -.5,0] t=.07 round=.02 color=ironC edge=edgeC
 
// the blade swings across the passage, the cog turns with it
anim pivot rz sin amp=58 hz=.42
anim cog ry sin amp=58 hz=.42