Blend between two Axis' in Nuke. Caution: The resulting Axis might be skewed while blending even when the sources are not! If there are time offsets on the input Axis' they need to be filled in manually since they are not taken into account automatically.

CK_AxisBlend.tcl

set cut_paste_input [stack 0]
version 10.5 v1
push $cut_paste_input
Group {
name CK_AxisBlend1
tile_color 0x9c0000ff
addUserKnob {20 CK_AxisBlend}
addUserKnob {3 time_offset0 l "time offset 0"}
addUserKnob {6 hold0 l hold -STARTLINE}
addUserKnob {26 space l "" -STARTLINE T "  |   "}
addUserKnob {3 time_offset1 l "time offset 1" -STARTLINE}
addUserKnob {6 hold1 l hold -STARTLINE}
addUserKnob {7 blend}
}
Input {
inputs 0
name Input0
xpos 730
ypos 62
}
Axis2 {
name Axis1
xpos 740
ypos 138
}
Input {
inputs 0
name Input1
xpos 950
ypos 62
number 1
}
Axis2 {
name Axis2
xpos 960
ypos 138
}
Axis2 {
inputs 0
useMatrix true
matrix {
    {{"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"}}
    {{"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"}}
    {{"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"}}
    {{"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"} {"lerp(Axis1.world_matrix(hold0 ? time_offset0 : t-time_offset0), Axis2.world_matrix(hold1 ? time_offset1 : t-time_offset1), blend)"}}
  }
name Axis3
xpos 850
ypos 138
}
Output {
name Output
xpos 840
ypos 254
}
end_group