Creating multiple keyframes

leeminardi — Mon, 07 Feb 2022 23:12:35 GMT

I created the following code to calculate the location of the end of a boom from a bus (trolley) to an overhead cable.

-- positions PointCable on line001 a distance LabelControl -- from PointBus -- v .01 2/6/2022 L. Minardi clearlistener() fn CalculateCablePoint = ( select $line001 cable = $ select $PointCable pCable = $ sM = [0,0,0] global delta = 0.1 global s = delta global L= 20. select $Bus BusT = $.transform select $PointBus pBus = $.position sA = 0.0 -- % along value for A sB = delta -- initial % along guess for B flag = true pA = interpCurve3D cable 1 sA -- point A pB = interpCurve3D cable 1 sB -- point B dA = distance pBus pA dB = distance pBus pB -- get to intervale containing solution for i = 1 to 10 while flag do (if dB > L then ( pA = pB sA = sB sB = sB + delta pB = interpCurve3D cable 1 sB dB = distance pBus pB ) else ( flag = false ) ) -- interval found, now iterate between A and B flag = true for i = 1 to 5 while flag do ( sM = (sA + sB)/2. pM = interpCurve3D cable 1 sM dM = distance pBus pM err = abs(dm - L) if (err < (0.01 * L)) then ( flag = false format ("i = %, error = % ") i err ) if dM < L then ( pB = pM sB = sM ) else ( pA = pM sA = sM ) ) -- end for pCable.pos = pM ) CalculateCablePoint()

It works for a single location of the bus. I am trying to enhance it to generate keyframes as the bus moves. I have tried adding a For loop for the entire program and then the following statements to create keyframes at the end of the code. Note, pM is the point location of for the point object PointCable which the boom references with a LookAT constraint.

select $PointCable pCable = $ slidertime = j with animate on pCable.pos = pM

The keyframes are created but they are all the location and do not track along the cable as the bus moves. Here's the version with the loop. Any suggestion as to how to get it to generate keyframes for each calculation of pM?

-- positions PointCable on line001 a distance LabelControl -- from PointBus -- v .02 2/7/2022 L. Minardi clearlistener() clearSelection --fn cp = --( --with animate on for j = 1 to 15 do ( select $line001 cable = $ select $PointCable pCable = $ sM = [0,0,0] global delta = 0.1 global s = delta global L= 20. select $Bus BusT = $.transform select $PointBus pBus = $.position sA = 0.0 sB = delta flag = true pA = interpCurve3D cable 1 sA pB = interpCurve3D cable 1 sB dA = distance pBus pA dB = distance pBus pB -- get to intervale containing solution for i = 1 to 10 while flag do (if dB > L then ( pA = pB sA = sB sB = sB + delta pB = interpCurve3D cable 1 sB dB = distance pBus pB ) else ( flag = false ) ) -- now iterate between A and B flag = true for i = 1 to 5 while flag do ( sM = (sA + sB)/2. pM = interpCurve3D cable 1 sM dM = distance pBus pM err = abs(dm - L) if (err < (0.01 * L)) then ( flag = false format ("i = %, error = % ") i err ) if dM < L then ( pB = pM sB = sM ) else ( pA = pM sA = sM ) ) -- end for pCable.pos = pM clearselection() select $PointCable pCable = $ slidertime = j with animate on pCable.pos = pM ) -- end for j

Re: Creating multiple keyframes

istan — Wed, 09 Feb 2022 21:45:35 GMT

for what reason you

a) always "select" nodes?

b) do "pCable.pos=pM" right before clearselection() ?

Besides, I'd use a different solution by sphere/line intersection.

Re: Creating multiple keyframes

leeminardi — Wed, 09 Feb 2022 23:15:57 GMT

@istan wrote:
for what reason you
a) always "select" nodes?
b) do "pCable.pos=pM" right before clearselection() ?
Besides, I'd use a different solution by sphere/line intersection.

@istan thank you for your comments. My post was to help me in solving a bigger problem that is better described in this thread. With help from @denisT.MaxDoctor the need for generating keyframes has been eliminated.

As for using a "sphere/line intersection" approach the task is more complex if by "line" you meant straight line.. The path is a spline and there may be multiple solutions or none at all. I think a numerical solution works best in such a situation.

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Creating multiple keyframes

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