{"job_id":"anim-job-7f043f02-8a03-48a7-a24a-878ebd84bbbd","request_id":"bulk-2026-05-20T10-21-44-856Z-14-physics.10.magnetism.electromagnetic-induction","status":"complete","asset":{"primary_url":"https://storage.googleapis.com/pupiltree-animation-assets/anim-job-7f043f02-8a03-48a7-a24a-878ebd84bbbd/walkthrough.mp4","thumbnail_url":"https://storage.googleapis.com/pupiltree-animation-assets/anim-job-7f043f02-8a03-48a7-a24a-878ebd84bbbd/thumb.jpg","transcript_url":"https://storage.googleapis.com/pupiltree-animation-assets/anim-job-7f043f02-8a03-48a7-a24a-878ebd84bbbd/transcript.vtt","interactive_url":"https://storage.googleapis.com/pupiltree-animation-assets/anim-job-7f043f02-8a03-48a7-a24a-878ebd84bbbd/index.html","scenefile_url":"https://storage.googleapis.com/pupiltree-animation-assets/anim-job-7f043f02-8a03-48a7-a24a-878ebd84bbbd/scene-source.json","duration_seconds":15,"byte_size":467416,"renderer":"html_three_js_local","parameters":{"style":"auto","executor":"native_render_executor","localPath":"/app/storage/assets/anim-job-7f043f02-8a03-48a7-a24a-878ebd84bbbd","control_count":2,"interactivity":"none","simulation_id":"physics.10.magnetic_effects.electromagnetic_induction","renderer_style":"three_js","durationSeconds":15,"render_manifest":{"jobId":"anim-job-7f043f02-8a03-48a7-a24a-878ebd84bbbd","request":{"gap":{"topic":"em-induction-flux","severity":"moderate","error_type":"concept_misunderstanding","memory_state":"fragile","display_topic":"Electromagnetic 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context.","narration":"Electromagnetic Induction"},{"label":"Mistake","visual":"Show the wrong approach and why it seems plausible.","narration":"A static magnet always induces current in a nearby coil."},{"label":"Correction","visual":"Show the right approach step by step.","narration":"Induced emf appears only when magnetic flux through coil changes."},{"label":"Concept","visual":"Highlight the key formula and the governing relationship.","narration":"induction. flux change"}],"title":"Electromagnetic Induction","sceneCode":"<!doctype html>\n<html lang=\"en\">\n<head>\n  <meta charset=\"utf-8\"/>\n  <meta name=\"viewport\" content=\"width=device-width, initial-scale=1\"/>\n  <title>Electromagnetic Induction: Flux Change</title>\n  <style>\n    :root{--bg:#0e121a;--panel:#1c232e;--line:#303449;--accent:#fc884f;--text:#faf9f8;--muted:#9f9ea1;--blue:#627da5;--green:#8decb0;--red:#df8279;}\n    *{box-sizing:border-box;}\n    body{margin:0;font-family:\"Plus Jakarta 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<p class=\"sub\">Why a static magnet does NOT induce current</p>\n    <p class=\"formula\">ε = −dΦ/dt</p>\n    <label class=\"control\"><span>Magnet Speed: <strong id=\"v-speed\">0.8</strong> units</span><input id=\"c-speed\" type=\"range\" min=\"0\" max=\"1.5\" step=\"0.1\" value=\"0.8\"/></label>\n    <label class=\"control\"><span>Coil Distance: <strong id=\"v-dist\">1</strong> (static)</span><input id=\"c-dist\" type=\"range\" min=\"0.5\" max=\"2\" step=\"0.1\" value=\"1\"/></label>\n    <ul>\n      <li><svg class=\"icon\" viewBox=\"0 0 16 16\"><circle cx=\"8\" cy=\"8\" r=\"6\" stroke=\"currentColor\" stroke-width=\"2\" fill=\"none\"/><circle cx=\"8\" cy=\"8\" r=\"2\" fill=\"currentColor\"/></svg>Flux = B·A</li>\n      <li><svg class=\"icon\" viewBox=\"0 0 16 16\"><path d=\"M2 8h12M10 4l4 4-4 4\" stroke=\"currentColor\" stroke-width=\"2\" fill=\"none\" stroke-linecap=\"round\" stroke-linejoin=\"round\"/></svg>Change in flux triggers EMF</li>\n      <li><svg class=\"icon\" viewBox=\"0 0 16 16\"><circle cx=\"4\" cy=\"8\" r=\"2\" fill=\"currentColor\"/><circle cx=\"12\" cy=\"8\" r=\"2\" fill=\"currentColor\"/><line x1=\"6\" y1=\"6\" x2=\"10\" y2=\"10\" stroke=\"currentColor\" stroke-width=\"1.5\"/><line x1=\"6\" y1=\"10\" x2=\"10\" y2=\"6\" stroke=\"currentColor\" stroke-width=\"1.5\"/></svg>Static = no change = no EMF</li>\n    </ul>\n  </aside>\n  <section>\n    <div class=\"stage\" id=\"stage\">\n      <div class=\"legend\" id=\"legend\">Static: ε = 0 V</div>\n      <canvas id=\"sim-cv\" style=\"position:absolute;inset:0;width:100%;height:100%;\"></canvas>\n    </div>\n  </section>\n</main>\n<script>\nconst controls = [{\"key\":\"speed\",\"label\":\"Magnet Speed\",\"min\":0,\"max\":1.5,\"step\":0.1,\"value\":0.8,\"units\":\"m/s\"},{\"key\":\"dist\",\"label\":\"Coil Distance\",\"min\":0.5,\"max\":2,\"step\":0.1,\"value\":1,\"units\":\"norm\"}];\nfor(const c of controls){\n  const inp=document.getElementById('c-'+c.key);\n  const out=document.getElementById('v-'+c.key);\n  inp?.addEventListener('input',()=>{out.textContent=inp.value;window.updateModel?.();});\n}\n(function(){\n  const cv=document.getElementById('sim-cv');\n  const ctx=cv.getContext('2d');\n  function resize(){const r=cv.getBoundingClientRect();if(r.width>0){cv.width=r.width;cv.height=r.height;}}\n  resize();new ResizeObserver(resize).observe(cv);\n  let lastTs=0;\n  \n  let magnetX=0;\n  let magnetPhase=0;\n  let dFluxPrev=0;\n  let emfHistory=[];\n  let fluxHistory=[];\n  \n  function glowDot(x,y,r,color,a){\n    const g=ctx.createRadialGradient(x,y,0,x,y,r*2.6);\n    g.addColorStop(0,color.replace('ALPHA',String(a)));\n    g.addColorStop(1,color.replace('ALPHA','0'));\n    ctx.fillStyle=g;ctx.beginPath();ctx.arc(x,y,r*2.6,0,Math.PI*2);ctx.fill();\n  }\n  \n  function arrow(x1,y1,x2,y2,color,headLen=10){\n    const dx=x2-x1,dy=y2-y1,l=Math.sqrt(dx*dx+dy*dy);\n    if(l<2)return;\n    const nx=dx/l,ny=dy/l;\n    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