Simple robot arm rig question

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Hi, I'm trying to make robot arm follow exact location of a null object.
It follows loosely, which unacceptable for current task. If I change solver to FABRICK it follows correctly, but does not respect limitations of rig points.

Here's a short demo:
https://youtu.be/L6zRtT4HPdM [youtu.be]

Hipfile:
https://www.dropbox.com/s/5ybinoaihsxf6r8/robot.hiplc?dl=0 [www.dropbox.com]

Does anyone knows how to make this simple setup work?
Thanks.

Attachments:
robot.hiplc (3.4 MB)

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Turn the tolerance down to 0 on the FBIK node, and disable the rotation weights on point 4.

I don't know why the default tolerance is so high, but its often the key parameter for making fbik hit its targets correctly.

With just that turned off the robot still couldn't hit its target, I went through toggling off the constraints to see which one was not allowing the solver to hit its target. Releasing point 4 allowed this, and had the least visual impact.

Playing a little more, I found you can turn the rotation limits back on, just give the other values a tiiiiny amount, so rather than the rotation limit being {0,0,1}, try {0.0001, 0.0001, 1}.

See attached vid.

Attachments:
robot_fbik.mp4 (5.1 MB)

http://www.tokeru.com/cgwiki [www.tokeru.com]
https://www.patreon.com/mattestela [www.patreon.com]
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Thank you very much, Matt! Works perfectly.
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