These Tentacle System components work with Fischertechnik components. It includes a base and a grip.

The Tentacle System allows you to create ad hoc stands and holders using a variety of connectors and grippers. This part lets you attach those ad hoc stands to a Fischertechnik model or attach a Fischertechnik model to a tentacle.

These print as two pieces each. You superglue the two parts together to make a complete base or grip.

You might notice that there is no peg for attaching into the slots of Fischertechnik pieces. There are only slots on these Tentacle System parts. That is because the pegs would just break off. And, there is no slot on the ends. That is because both parts are radially symmetrical so you can just rotate it by 90º if you need a slot on the “side".

The reality of FDM-printed Fischertechnik parts is that they don't fit nearly as well as actual Fischertechnik parts fit because the printer has an accuracy of about 1/3mm and the pieces are designed for an accuracy much, much smaller than that. It would work with a resin printer.

For an FDM printer you might need to scale up or down the part that attaches to Fischertechnik bricks. The other part (the grip or base) must not be scaled or it won't work with the tentacle system. In both models the part that attaches to the Fischertechnik parts is fairly quick to print by itself, so you can try a few different scales to see what works for your printer.

Also check out the Fischertechnik Base and Grip by Juh!

You can learn all about the Tentacle System here: https://3ddoodle.com/tentacle-system/