The blending does not work for me. When dropping the blend factor below 1 the IK CHOP doesn't do its job anymore, it seems to be broken when I activate the blending.

This seems to work for me. I'm using Houdini 8.0.383 on WinXP SP2. Perhaps you could post an example hip file.

I'm using the same version. Maybe I'm doing something wrong. I saw the “IK FK Blend and Huds” video for Houdini 6 but I cant't get it to work.

You have the export (orange) flag turned on in the InverseKin CHOP *and* the bone's Kinematic Solver parameter is set to use this InverseKin CHOP. You have to pick one method and if you want IK/FK blending, you have to use the Kinematic Solver parameter.

To fix this, turn off the export (orange) flag in the InverseKin CHOP, save and reload the file.

Cool, works great the blending!