CGTalk - Tracers in Shake

Hugh

06-05-2007, 12:33 PM

Motion blur will do this quite well for you......

Track your moving point, and then link a Move2D node to the xShift and yShift values. Set the Move2D to have "useReference" turned on, and then turn on motionBlur. For the trail to be behind, set the shutterOffset to be "-shutterTiming" and then increase the shutterTiming for the length of tail you want.

Here's an example:

RGrad1 = RGrad(500, 500, 1, noise(time / 10) * width, noise((time+100) / 10) * height,
1, 20, 0, 0.5, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0);
Move2D1 = Move2D(RGrad1, Stabilize1.xShift, Stabilize1.yShift,
0, 1, 1, xScale, 0, 0, width/2, height/2, "default", xFilter,
"trsx", 0, 1, 5, -5, 1, time);
Stabilize1 = Stabilize(RGrad1, 1, 0, "1 point", Linear(0,412.618@1,404.224@2,393.845@3,381.27@4,366.813@5,350.427@6,332.876@7,314.489@8,296.001@9,277.622@10,259.739@11,243.415@12,230.266@13,221.122@14,216.329@15,216.243@16,220.884@17,229.61@18,241.954@19,256.934@20,273.177@21,289.837@22,306.102@23,321.29@24,334.798@25,346.001@26,354.841@27,360.966@28,364.434@29,365.665@30,364.688@31,360.559@32,352.7@33,340.349@34,323.407@35,302.114@36,276.891@37,248.532@38,219.102@39,190.262@40,162.887@41,137.524@42,115.95@43,96.6102@44,80.9891@45,69.0711@46,60.8641@47,55.7039@48,52.993@49,52.118@50,52.1219@51,52.9344@52,54.4266@53,56.6532@54,59.4852@55,62.868@56,66.5204@57,70.3758@58,74.1024@59,77.4891@60,80.4618@61,83.8563@62,88.0946@63,93.911@64,101.43@65,110.907@66,122.22@67,135.395@68,150.309@69,166.118@70,184.895@71,205.352@72,226.88@73,248.606@74,269.294@75,287.524@76,302.993@77,315.266@78,324.325@79,330.509@80,334.102@81,334.766@82,332.212@83,326.212@84,316.891@85,304.368@86,289.27@87,272.149@88,254.196@89,236.294@90,219.93@91,205.04@92,192.024@93,180.884@94,171.97@95,165.235@96,160.813@97,158.134@98,157.032@99,156.587@100),
Linear(0,155.47@1,154.318@2,152.595@3,150.239@4,147.13@5,143.497@6,139.376@7,135.978@8,131.458@9,126.935@10,122.771@11,119.822@12,119.177@13,121.165@14,126.435@15,135.064@16,146.986@17,161.13@18,178.868@19,199.154@20,221.388@21,245.447@22,270.204@23,294.22@24,316.533@25,336.408@26,353.396@27,367.275@28,378.005@29,386.165@30,391.892@31,395.04@32,394.935@33,391.388@34,384.138@35,373.2@36,358.908@37,341.822@38,322.822@39,302.685@40,282.626@41,263.517@42,246.282@43,231.857@44,221.314@45,214.579@46,211.79@47,212.681@48,216.618@49,222.626@50,229.872@51,237.818@52,246.22@53,254.509@54,262.228@55,269.079@56,274.654@57,279.087@58,281.935@59,283.521@60,283.611@61,282.63@62,280.763@63,277.911@64,274.513@65,270.697@66,266.759@67,262.904@68,259.615@69,257.048@70,255.728@71,256.392@72,259.411@73,265.138@74,273.368@75,284.075@76,296.618@77,310.345@78,324.724@79,339.243@80,353.204@81,366.513@82,378.634@83,389.333@84,398.4@85,405.423@86,410.63@87,413.892@88,415.704@89,416.38@90,416.357@91,415.626@92,414.033@93,411.587@94,408.29@95,404.173@96,399.384@97,394.158@98,388.665@99,383.208@100),
1, 1, 2*width/3, height/3, 0, 0, 2*width/3, 2*height/3, width/3,
2*height/3, "default", xFilter, "trsx", 0, 0.5, 0, 1, 1,
0, 1, "v2.0", 100, "1/256", "luminance", 0.3, 0.59, 0.11,
0.75, "use start frame", 0.5, "stop", 1, 0, 25, "track1",
105.600067, 204.0715, 334.588684, 429.257874, 16.7296143,
292.9419, 240.591827, 523.254761, "track2", 316.6667, 350,
150, 183.333344, 300, 366.6667, 133.333344, 200, "track3",
316.6667, 350, 316.6667, 350, 300, 366.6667, 300, 366.6667,
"track4", 150, 183.333344, 316.6667, 350, 133.333344, 200,
300, 366.6667);
Reorder1 = Reorder(Move2D1, "r000");
Over1 = Over(RGrad1, Reorder1, 1, 0, 0);