Quick robot arm and hexapod study from earlier today for practice based on some of the reference i posted a few weeks ago on Facebook for my students.... DL link on my website if you want to mess around with the models.....Because sharing. :)
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For the robot arm, it's all decimated down to keep the file size low, but you can 'split to similar parts' or 'group split' in ZBrush to get the individual pieces and re-dynamesh to get a more dense form to modify and build something more complex.